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My guess is this works for all ATI cards (4XXX and up) but it may only work for certain cards only

I've tried countless test, and I've concluded that for my 6870 at least, I get up to 5% Mh/s increase by forcing idle clock for mem (300 from 1050). All tests I have done are with OCed core clock (1000~1045 from 900)

I used MSI afterburner. At 250 mem clock I got a 10% DECREASE, at 900~1200 mem clock I get a 5% DECREASE from mem clock at 300

Give it a try ;)

http://event.msi.com/vga/afterburner/download.htm

Go in your MSI afterburner folder in program files (X86 for me) and edit the msiafterburner.cfg

where you see [ATIADLHAL] make sure it looks like this:
[ATIADLHAL]
EnableUnofficialOverclocking   = 1
UnofficialOverclockingEULA   = I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it
UnofficialOverclockingMode   = 2
AccessibilityCheckingPeriod   = 0

in order to get lower memory clocks please follow this:

1- Open MSI Afterburner
2- Set Memory Clock to the lowest possible or to desired amount
3- Click Apply
4- If Memory Clock is not to the desired amount, close MSI Afterburner
5- Repeat 1 to 4 until desired amount is reached
6- Set Fan Speed

Same can be done to get higher core clocks

Donations are always welcome :) 167q1CHgVjzLCwQwQvJ3tRMUCrjfqvSznd

EDIT: It seems the most effecient memory clock is between 300 and 400. In my case, for 1020 core on a 6870 it is 344, you should experiment as well ;)

no problem.... in order to get lower memory clocks please follow this:

1- Open MSI Afterburner
2- Set Memory Clock to the lowest possible or to desired amount
3- Click Apply
4- If Memory Clock is not to the desired amount, close MSI Afterburner
5- Repeat 1 to 4 until desired amount is reached
6- Set Fan Speed

Same can be done to get higher core clocks

5870 here.

Going from 1200->275 mem makes no difference, and 275->900 makes it run 2-3 mhash higher, but the card is a lot louder and hotter at this setting as well.

So each card probably has a sweet spot for mem clock

Just went there ;)

I just restarted my comp and my Mh/s are back to normal, before, my Mh/s were 5% lower than usual for no apparent reason. Also, my CPU mining doesn't really affect my GPU mining anymore (before it would lower it by 10Mh/s, not it lowers it by 1 if not less

If it is said here in bitcoin forum, instead on IRC, it stays forever, (until mods deletes), so not only advanced, but also new , no voice user found it useful.



UnofficialOverclockingEULA   =1 ,i put & cant make it to work MSI. thanks for saying that i have to write a long sentence & promise MSI.

I think he meant just to talk because he likes my posts so far...

As for the 2nd part could you rephrase? I did not get it. For some people the =1 is fine, for others you gotta write the whole thing, so I just gave you the long version

u may be right. before i tried with 1 & it didnt help MSI to OC. Now after that long sentence, i can able to go to 300Mhz from 1050Mhz of mem clk & i have to thank u for creating this post.
By decreasing mem clk, i dont see much difference in Mhash/s , may be i didnt look carefully.
But it helped me to lower temp.
I have 6870 & running at 1038 core clk, 1050 mem clk, 100% fan & getting 265-268 Mhash/s with temp 74-75C.
Now with 1038 core clk, 325 mem clk, 100% fan, i am getting 267-269 Mhash/s with temp 65-66C.
around 10C reduction in temp by lowering mem clk, which i never expected.

Try 300 mem clock exactly...

Yea temp reduction helps... though you temps are high for 100%... I get those temps with 57% fan and with 1045 core

mem clk 300 don't do much. but for me mem clk 375 gives 271-273 Mhash/s & any other mem clk gives less, 265-270 only.

Use the freeware version of xchat -- http://code.google.com/p/xchat-wdk/

Isn't this just a buggy overclocking tool? You can just use AMDs GPU clock tool if you want to overclock beyond the Overdrive limit.

So far MSI's Afterburner is the best OC tool I've used

So many people have benefitted frpom this yet noone feels the urge to donate?  ::)

Anyone else wants to share their experience? be it if it just lowered your temp by 10C or if it actually gave you an Mh/s increase?

Thanks person who donated 0.5 btc :) the 1st donation I ever received  :D

Lowering the memory clock is lowering your hash/s by a very small %. From me, from 1250 MHz to 625 MHz is decreasing my performance by something smaller than 1%.

My 3 HD 6950 are on underclock (725 MHz core, 625 MHz ram) and undevoltage since the beginning. The overall system consumption is around 350W insted of 650 W for a 10% higher has rate.

Interesting... with my 6870, my hashrate went up ~5Mh/s AT LEAST... so somewhere around 2~3%, and my temps by 5~10C I'm not too sure (my fan speed varies)

Sent a donation, thanks for the tip. Lowered my temps from 72C to 67C on my 6850. The hashrate did not lower either.

the hash rate on poclbm in linux on a 5870 lowers drastically (a good 10mhs) when the memclock is at 300 compared to 900. you can do it with radeon bios editor though, since MSI afterburner isn't available in linux.

I'll bump this for whomever missed it before

bump so that every can benefit from this! at worst your temps and power consumption go WAY down!

Yeah if you're using Windows - reason being if I'm not mistaken in Linux performance also suffers if you lower the mem clock, no?

But yeah, lowering the mem clock works for me in Windows and it does lower power consumption and temps. Not sure about "WAY" down though. I does cut quite a bit of "amps" off the VRMs powering the memory especially for me with my 4 GB of VRAM. I'd say it probably lowers power usage by 30 watts easily.

Well MSIa doesn't work for linux... but it would be weird if mem clock reduction makes performance suffer in linux.

30W is WAY down in my book :D what card are you using?

If you are feeling really frisky, the VTT voltages can be lowered via BIOS on a 5970.

Sapphire Radeon 5970 OC edition..4 GB VRAM...runs stock at 850 Mhz with meme 1200 Mhz

It is weird, but that's what some people have been saying on this very thread. Check back a few posts. In windows lowering mem does not affect performance at 300 Mhz...

Hehehe..not that frisky. Well, I may do that in a dedicated miner, but I won't mess around with that on the card which I intend to use for gaming as well. The reason being that when I want to game I do intend to up the mem clock back to stock speeds :) The lower voltage may not work with 1200 Mhz mem clock because this is an OVERLOCKED setting..stock mem is like what 900 Mhz for the 5970, no?

My gaming OC is 940/1100 or 940/1150 (stock for my XFX BE edition). during mining it is at 1020/300

What voltages do you use--in both situations--for the GPUs and memory?

Damn! 1020 for the GPU core?! Gotta love those better binned cards. What temps are you seeing at that clock rate, and is the clock 100% stable?

This is not new information. I used it with 4850 , and 5830 and it worked, but with my 5870 I get a 50mhash drop.

No voltage change. These are 6870s! 1020 core is pretty much 100% stable for mining if fan is at least at 45%, but not for gaming. 1040 on a single card was 95% stable for mining, as long as I did not too much GPU related things on my PC at the same time, and fan was at 50%, 1045 same but like 90% stable. After that 1048 was perhaps 85% and 1050 was 50%.

up to 1048 is 100% stable if I put -f 120, 1040 was 98% stable if -f 60 was put

does anyone know why this works from a technical point of view?

i could understand if it didnt have any effect but having a positive effect i dont get.

I too would like to know. Any GPU guru's around here?

I cant get MSI to lower my mem clocks lower than 1k on 5970..

Check this link out:

http://bitcointalk.org/index.php?topic=4292.0

Ye shall see the light in the very first post :)

My best guess as to why you can see an increase in hashrate is that the card might use tighter memory timings when you lower the clockspeed. Mining doesn't use very much (if any) RAM so there is still more than enough bandwidth even when underclocked. Tighter timings = lower latency = faster.

Oddly, for some cards this works and for others it doesn't. I have a 5830 and a 5870 in one system, both with the RAM underclocked to 450. The 5830 shows no difference in hashrate, but the 5870 takes a 20-30 Mhash/sec hit. These cards are in a dedicated mining system using the same drivers. (Linux + 11.2 + SDK 2.1)

Did you happen to try 300 on the 5870?

Just retested this on a 5870 running in my windows machine. The card is overclocked to 930MHz core with drivers 11.2 + SDK 2.2

1200MHz = 352 Mhash/sec
450MHz = 328 Mhash/sec
300MHz = 305 Mhash/sec

The cards run faster in Linux, but the effect of lower memory clocks is similar.

EDIT: I would test this on Linux but changing the clockspeeds outside of the overdrive limits requires BIOS flashing. It's much easier just to test in Windows where I can set it with MSI Afterburner.

Strange. I wish we knew more about this instead of just hit and miss.

Hmm, so the anandtech article on the 5870 mentions:
http://www.anandtech.com/show/2841/12
Maybe with higher memory clocks some computation is delayed because the memory needs to retransmit again. This may be the reason some people see increases in performance and others don't. (some people's cards can transmit 100% at the stock speed and other people's can't)

On both my 5870 and 5850, lowering the memory clock decrease hash rate. Does anyone with these 2 cards see the opposite?

Well that's odd...why does it not affect hash rates on the 5970?

My 5970 is currently clocked at 850 Mhz and 300 Mhz memory and currently pulling 318.2 Mhash/s per GPU...can anyone else corroborate this?

Yes, I get a noticeable increase with both of those cards.

XFX 5870 here

I dropped the memory clock to 300.

Mh/s is holding at 336 now where as before it was fluctuating from 330. My temp appears to have dropped by 5c. I'll do more testing but it's looking good so far.

What miners/OS/Catalyst/opencl are you guys running?

Newest poclbm / Win7 64 / 11.3 / whatever is included with 11.3

11.3 uses SDK 2.3 (ie opencl) as far as I know..

I've go the same setup btw.

Glad it is working for so many of you

OS   Win7 x64
Cat   11.3
SDK   v2.4

Please try this & give confirmed confirmations.

The MAXIMUM STABLE CONSTANT hash/s is obtained by a formula which i tried & found out for my HD6870. Instead of varying hash/s, it gives some what constant hash/s
Memory clock = (core clock /3) + 14
Please try, test & confirm with your results & please put your data here with your Graphics card & hash/s you get (you can add OS, 32 or 64, catalyst version & stream or APP version also).

Donations & loans are always welcome.
Thanks.

2x5870 950core, 330mem: 316MH/s each
2x5870 950core, 1000mem: 358 MH/s each

-EP

thanks!!!! However my numbers are different...

OS: Windows 7 Pro 64-bit
Cat 11.4 stream 2.4
Card: 6870

Hashrate @ 300 1020 core= 263500 kh/s
310 = 264400 kh/s
320 = 265500 kh/s
330 = 266300 kh/s
340 = 266800 kh/s
350 = 266750 kh/s (varies a bit more)
354 (1020/3 +14) = 266500 kh/s
360 = 265500 kh/s

After further testing:
341 = 268100 kh/s
342 = 267100 kh/s
343 = 267350 kh/s
344 = 267150 kh/s
345 = 267000 kh/s
346-349 = gradually down until 266750 kh/s

So best mem clocks are 341... 341 = coreclock/3 + 1

Trying with 999 core now

300 = 259000 kh/s
330 = 261550 kh/s
334 (999/3 + 1) = 261500 kh/s
340 = 261600 kh/s
347 (999/3 + 14) = 260800 kh/s

at this point I can see the /3 is the wrong correlation with the core clock.

337 = 261000 kh/s
338 = 261500 kh/s
339 = 261600 kh/s
340 = 261600 kh/s
341 = 261650 kh/s
342 = 261500 kh/s
343 = 261500 kh/s


So far, it seems 341 is a very good mem clock to start at

i am running in windows 7  32bit aero enabled , 6870

at present 1042 core & 361 mem with 100% fan & 73C temp
getting 271-275 Mhash/s
with flags, -v -w128 -f1

-v -w128 -f 120 here

as i said in some posts before, which i forgot, due to get mine more, 1042 crashed.

so now back to 1038 core & 360 mem, 100% fan with temp 70C
268- 273 Mhash/s , -v -w128 -f1

Bump b/c it seems to work =)
Using afterburner I lowered the memclock on my 6850 to 300 and raised my core clock to 900..seems to be the sweet spot for my card.
Im up to 191-193 Mhash/s from 169-172

So essentially you were able to maintain the same thermal profile yet increase your performance :P ? If so then congrats!

Is there anyway to run MSI Afterburner to automatically Over clock of memory also?
I did my best & it loads core clk as 1038 on startup, but memory 1050 only, then i move the slider to minimum, for me 525, apply & restart MSI AF.
Restarting shows core as 900 & mem as 1050, but clicking saved profile, brings it to 1038/360.
I want MSI AF or if any other software there to automatically apply OC, so no human interaction needed to mining.
Tried with MSI AF 2.0 & 2.1

EDIT: With out loosing warranty or guarantee & also no flashing & only software based.

Flash the BIOS with whatever settings you wish.

I can't loose my warranty or guarantee.

if you're overclocking ... you're already losing your warranty

Not always. Some companies (like XFX & EVGA) will let you overclock and still honor your warranty.

doesn't matter, they can't find out you were overclocking unless you do something obviously stupid to show them you were.

Of course if you try to return a card that you damaged by overclocking, and this is not covered by the warranty, you would be committing fraud.

yes, but if it was not damaged by OCing, but I did OC it, I wouldn't feel bad by committing "fraud" to get a replacement... I never had to though, all the cards I've owned are Reference design XFX cards

Wow, I dropped my 5870 memory clock to from 1200 MHz to 180MHz and saw an increase of 4-7Mhash/s. More importantly my temperatures dropped by 10C.

I can get my memory clock on my 5750 down to 575 MHz after restarting Afterburner once, but I can't get it to go down any further. Got tips?

By the way, I was able to push my core clock all the way from 700 to 870, gain about 40 MHash/s, and lower my temps by almost 20 degrees Celsius :D

Don't drop mem clock below 300 Mhz. If u increase it to 300 Mhz, u will see more gain.
my trick is to use core clock/3 + 14= mem clk gives maximum hash.

If your core clock is 990, then 990/3 + 14 = 344 gives u maximum hash/s &  of course 10 C drop in temp.

I remember you saying that when I first joined the forum a few weeks ago. No matter how hard I try, 960/390 is the best stable config I can get away with on my 5830. It drives me nuts. I can usually get it to run at 380 on Memory Clock for a bit, or 970 on Core, but it always just ends up freezing or crashing the drivers for the card. If I tried to drop my clock to 334 (per your equation), my computer would die outright. Win 7 64. What am I doing wrong? :P

Exit/close MSI afterburner completely
Open with notepad the following file
C:\Program Files\MSI Afterburner\MSIAfterburner.cfg

Go to end & u will see.
[ATIADLHAL]
blah, blah....
[NVAPIHAL]

Replace
[ATIADLHAL]
blah, blah....   with


[ATIADLHAL]
EnableUnofficialOverclocking   = 1
UnofficialOverclockingEULA   = I confirm that I am aware of unofficial overclocking limitations and fully understand that MSI will not provide me any support on it
UnofficialOverclockingMode   = 2
AccessibilityCheckingPeriod   = 0

Restart Afterburner, now u can move as u want in core, mem clk's

If u installed catalyst control center uninstall it. It won't allow to go more & interfere.
Just install this 4 only for mining. Some times even VC++ not necessary.
ATI display driver, ATI catalyst install manager, APP 2.3 (or) SDK 2.1 & VC++

I am running HD6870 at 1038/360 with 100% fan & temp <73C getting 298-300 Mhash/s
Windows 7 32 bit, Aero enabled.
Miner with -v -w128 -f10
If i run with -f1 some times system gets crashed, if i use youtube or accidentally open a site with flash...

Also may be what you get is maximum & can't go beyond.
Default core clk for 5830 is 800, while 5870 is 850 & 6870 is 900.

I have the same issue with Flash...if you haven't, you can right click on a YouTube video, go to "Settings" and uncheck "Enable Hardware Configuration" on the Display tab (I know you know this, but lots prolly don't).

System specs for me:

Win 7 Home Premium 64-bit w/Aero and XFX 5380
Miner - Phoenix - running with -k poclbm VECTORS BFI_INT FASTLOOP AGGRESSION=7 DEVICE=1
(no hashrate change with smaller worksize after BFI_INT)
Current stable config @ 960/360; current temp 77C (varies between 70 and 80 depending on room temperature)
Current hashrate ~ 288-290MH/s
Software looks good...no Catalyst Control Center lurking about. Currently running SDK 2.1 and 10.7 display driver.

I may be at my max with this here Windows box. :P I'd love to get a 970 or 980 stable config, tho...seems to get damn near 300 MH/s when I have it up that high.


At current I can go up to 1040 in MSI...no idea if that's wise, but the slider goes over that far. :P

Instead of phoenix use poclbm new one.
Both give same hash only, but when i run phoenix, some times i FEEL some thing is wrong(don't know what it is)
Also [Tycho] mentioned that with his pool phoenix has some problem.

Tried that already, didn't work :-\

I use Tycho's pool and phoenix and everything seems fine on my side

http://bitcointalk.org/index.php?topic=3889.msg97330#msg97330

Can't hurt to try it, right? I used Kiv's GUI miner when I first started because my command line was super rusty (and still is, as evidenced by other replies I've made around here in an effort to be helpful). I think I can handle poclbm in the rough now. I'll let ya know. :)

Stales are reasonable on Phoenix with the newest version...no issues to report. The goal here is to squeeze some more MH out of this card, so I'll be back after I crash...errr...test my system.

If you guys see my sig at 0 MH/s, you'll know what happened. :P

U sure, you installed only these 3 & removed catalyst control center?
ATI display driver, ATI catalyst install manager, APP 2.3 (or) SDK 2.1 & VC++
Some times even VC++ not necessary.

In Afterburner, after u set eula that u agree....
u will reduce mem clk to min 525, clk apply, exit afterburner & restart after burner.
Now u will see the mem clk is 525, but the slider will be in middle. Move it down further to mem clk u want & apply & minimize afterburner.

Didn't get much of an improvement over Phoenix with straight POCLBM, but I did manage to stabilize the system at 970/380, which is nice. Hashrate is slightly higher when I'm using the computer, which is always a plus. I may have to go back to 960/390 at some point if this crashes a lot, but I'm up and running for now. I did briefly see over 300 MHash/sec right before my system crashed. :-/

I have a suggestion, but it may be hilarious. Instead of 10.7 driver & 2.1 stream, Try the latest ATI.
Thats 11.4 driver & 2.4.595.10 APP.
Here's the link, http://www2.ati.com/drivers/11-4_vista64_win7_64_dd_ccc_ocl.exe
But before installing it uninstall all ati/amd graphics drivers completely using Driver sweeper from www.phyxion.net.
I wish that helps u reach stable 300+ MH/s

I laughed pretty hard when I read this...but I suppose it's worth a shot.

Strange development over the last few hours...was unable to stabilize that 970/380, so I'm back at the last known working config (960/390). Also, even running at the reduced core clock, I was seeing temps spiking at 82 and 83. Switched back to Phoenix...lost about 5 MHash/sec and the temps are back in the mid-70's. I've also got the big cooler running...the cats hate it, but they aren't making me any Bitcoins, last I checked. :P

So I did the tweaks to afterburner cfg file, and was able to lower my mem clock from 1000Mhz to 500Mhz, but the slider will not allow for more.

I see several of you posting going down to the 200, 300 and 400Mhz range.  How?

I have a 5830 under Win7 64bit.  Thx.

Slide it to 500, hit apply, close msi afterburner. Then when you open msi again it should let you go down lower.

+1

So far, i can't able to find a direct way to go 1038 & 360 directly.
The only way is to apply, restart & change.
So, you can't just start mining rig & go away. you have to change mem clk & after you can leave mining rig, until, it restarts again. 

Cool.  Gained about 2-3M hashes by dropping it down to 339.  341 and 339 give me the same.  Anything slightly higher or lower give me like 1M less.

This also decreased my card power by 20W, and temperature by about 5C!  ;D

Currently running a single 5830 @ 920Mhz.  Agression is at 7.  At 11 I will gain a few more M hashes.  I get 264Mhash/sec now.

Please try mem clk at this speed, 920/3 + 14, that's 320.66= 320 mhz & post how much Mhash/s u get.

At 920/320 I get 263-264.

At 925/324 I get 265-266.

You might be able to OC that all the way up to 960. Hell, I saw Frankiebits say he had his at 1000 for a while...though I couldn't tell you how he did that. I run mine at 960, and I seem to have one of the most unstable systems on the forum in terms of getting the speeds everyone else is. 960 is damn stable, though. :P I get around 290 or so while using the computer, but I can't get my memory clock as low as I'd like. I'd say edge the core clock up by 5 and just keep an eye on it for a bit. Sometimes I'll launch like 3 Firefox tabs with YouTube videos just to make sure the system is stable before I OC it more.

Edit: If you do this, keep an eye on the temp. I use a tool called GPU Observer...it's a Windows sidebar gadget. Too lazy to link. :P

Wow... 960 seems kind of high. I may try it though.  I use MSI afterburner to monitor temps (dual monitors).  @ 925/324 @ 60% fan speed, I run at 61C.

Man, how are you getting 290 Mhash/s with a 5830 @ 960Mhz.

I'm at 960Mhz now and averaging 275Mhash/s....

whats your mem? are you using pheonix 1.4 or the newest poclbm?

1.4.  Also, I forgot to mention I was using aggression = 7.  Now with Agression = 11 I'm at about 285Mhash/s.

Whats strange is I've run into a wall.  I can increase my core to 970 or 975 and get Zero increase in performance over 965.  Strange...

I'm now at 965/185 running strong @ 62C @ 60% fan.

Also, I'm running Win7 64bit with Stream SDK 2.4.  I read some people say 2.1 is better and I'll get better results?

yup with the 5XXX series, there is a specific sdk (2.1) and a Cat version (10.something) that is best

After some more tweaking, my best for core 1020 is 344 on my 6870

Impressive. Can you share that?
I am on win 7 32, with new poclbm or phoenix 1.4 ,in 6870,  only able to get 296 Mhash/s with 1029/359 or 301 Mhash/s with 1038/360.

I meant 1020 core and 344 mem is my sweetspot lol

I only get 301~302 Mh/s

312 with phatk

I didn't read the last 2 pages but I wanted to give my opinion of what is happening, it's either:

1. Ram Latency is being reduced (as was already mentioned)

2. Clock dividers being used between core and memory are hitting a favorable divider at the "sweet spot", favorable meaning most efficient


This kind of thing used to happen for example on p35 chipsets, there were some bus frequencies that while lower, were faster due to "memory latches" (latencies used) and ram dividers

I think it is number 2, as between 344 and 343 or 344 and 345, I lose ~2Mh/s

I can't seem to edit the msiafterburner file. It won't let me save. I tried to uninstall Catalyst but anything that will install drivers for my card always has catalyst in it. Can one of you kind souls please link me to driver only without catalyst along with the package? Thank you very much in advance!

for how long do you measure your hashrate? with -a 64 mine is still jumping arround randomly more than the difference a small change to the memclock makes.

for how long do you measure your hashrate? with -a 64 mine is still jumping arround randomly more than the difference a small change to the memclock makes.

My results with 5770:

http://smpake.com/data/img/5770mem.png

thanks for the graph, my 5850 is now on 300 mem/970@ 1,162V @ Lüfter 100% 70°C with 372 MHash/s with the Blocksize of 256.

Using pocplm with an HD5770 (-v -w128), no matter what I get maximum hashes at default memory clock (1200). If I lower it at 300, I get like 5 MHash/s less..
EDIT: Who says the truth?
http://gyazo.com/e5a13f40d141853d25c81b25cc8a6de7.png

Reason is very simple. You have installed the express version of catalyst driver, which even if you not selected AMD overdrive to OC, controls the clocking ability & it completely denies & don't allow to hash more, even though you are lowering mem clock & it is shown in Afterburner & also in Overdrive.
AMD overdrive controls the mem clock in background which you can't see.

Simple solution, Uninstall all the catalyst driver using driver sweeper & then reinstall using latest or any catalyst driver with CUSTOM install & install only these 3, ATI display driver, ATI catalyst install manager, APP 2.4.

Check this, http://forum.bitcoin.org/index.php?topic=6458.msg168021#msg168021
Lowering mem clock reduces temp up to 10C & also increases hash rate.
If you have 6870 card use these, mem clk = (core clk/3) + 14.
If you have 5870 card use these, mem clk = core clk/3.

This gives the MAXIMUM hash with MINIMUM temperature.

Perfect, perfect and perfect!
Now I don't get any hash/s loss, and the temperature reduced.
I did these things
1) Uninstall AMD Overdrive
2) Use Driver Sweeper and clean all ATI drivers
3) Reboot in Safe mode
4) Run Driver Sweeper again in Safemode
5) Install ATI 11.5 using only the 3 selected things you told me.

Still, I can't know at which temperature is my GPU.
http://gyazo.com/8c1967dce80b3d95b7163478195fbcb6.png

It seems to depends on the card, not the card model.
For my 5870 GPU is set to 900 (it's unstable for higher values) and the performance does not change more than 1% within the range 175<=MEM<=900. Thus I've set 175 for energy & noise reasons.

I have 2 asus EAH5870 & 1 sappire HD 5870 for my SH rig & every card is mining at 430+ Mhash/s with 975 core clk & 325 mem clk in windows 7 32 bit, with aero enabled.

If you uninstalled everything & installed only the 3 i said, you won't have AMD VISION Engine Control Center (it is the catalyst center which blocks UC of memory). Just run the setup again & select uninstall & uninstall Catalyst control center.
http://i55.tinypic.com/2rh1zqb.jpg

In your picture,in Afterburner even though fan speed says 68%, fan tachometer, RPM says 0, means fan is not running or may be fan connector fault.
Remove dust from fan to reduce temp.
Also,in Afterburner set fan speed in to manual instead of AUTO & slide it to 100% & see whether temp drops or not.

Trying to lower memory clocks on my 5830 below 650 is giving me instant blank screens with vertical blue lines, seemingly these speeds are not accepted by my hardware. I've tried 600, 500, 300, all with the same problem. Moving from 800/1000 (stock speed) to 950/650 has been rock stable but i'd like to drop it the memory clock farther if it will save me temp, energy and probably card life. Anyone else have this problem?

I saw the posts about completely removing drivers and reinstalling a limited set, but I haven't had trouble changing clocks until I try to apply mem clocks 600Mhz or less... so I don't think its a problem with the ATI drivers interfering.

Until u try, u can't see problems or solutions.
Seeing post is NOT trying practical.
Install only 3, & if you still can't lower mem clk, then i accept 5830 won't allow to go mem clk below 650.
If you look at overdrive, core clk & mem clk when not mining, it will be in 300 & 300 only.

I had the exact same problem, install TriXX 4.0.1

also, in a multi-card rig with only one monitor, you can only change the clocks of the card the monitor is connected to at the moment (unless you use dummy plugs)

Unistalled AMD Vision and all the not needed things. I get the same MH/s as before, so it seems that CCC wasn't the problem.
Also, MSI Afterburner says that fan rpm are 0, but if I put it to 100% I hear a fucking noise, so it is working :D
I'm still getting high temps btw.
There isn't dust in the fan, so the problem must be another. Could it be the thermal paste? Or the plastic cover made by ASUS?

Thought I'd post my results on underclocking memory.

I run an ASUS 4870 DK using poclbm -w 256 -f 60.
Trying the clocking around I got to ~92.5 MH/s @ 830 core and 900-300 memory using MSI Afterburner.
After trying to go lower I started to see a hash boost when going below 250. Going lower, I found that @ 173 and lower my card immediately froze, and less than 185 it would crash and do a VPU reset after a small time.
But at 190 is a sweet spot for me. Hashing increased by 2-3 MH/s compared to anything above 250, and as a bonus the card runs a lot cooler, practically flatlining at 61 degrees at the moment.
It is also pretty effective, pulling that by only using 85w over when sitting idle, or about 1.1 MH/J.

http://imageshack.us/photo/my-images/196/unled1yxj.jpg/ (http://imageshack.us/photo/my-images/196/unled1yxj.jpg/)

I'm a happy new miner.  :D

Edit: Pumping core up to 840, my card sits pretty stable at 95.7 MH/s and 62 degrees. Using -w 256 -f 10 makes me go up to 98.4, though windows becomes sluggish then.
I can run at 850 core and get 100 MH/s, but at that point if I so much as touches anything that causes extra GUI operations, the drivers crash.
Before when I clocked core to 850 with standard memory clocks, the card would crash instantly, even when not running the miner. So underclocking memory is a great success I'd say.

Great advice, thank you.

6870
Memory: 357
Core: 1025
Hashing: 314,36MH/s

Windows 7 x64
Catalyst 11.5

phoenix -u http://:@:/ -k phatk VECTORS BFI_INT FASTLOOP=false DEVICE=0 AGGRESSION=11

It works great!

I just started mining (BTCmine pool) yesterday with my new X2 255 (under-volted/clocked tot 1.1volt and 2.4Ghz) and an Asus EAH5770 GPU.

GPU 899Mhz / 1,160 volt
300 Mhz mem
197Mhash/s

Power consumption: 170Watt.

Thanks PcChip, that worked like a charm! I should've mentioned I was using a sapphire card in my orig. post.

Sapphire users, check out TriXX, it seems to work better on our cards than the oft-recommended MSI Afterburner. No need to mess with ATI driver install, the default standard set is fine.

>300Mh/s, 5830 @ 996/300. Custom fan control keeps it around 65C, which I think is acceptable for long term use.

Sapphire Trixx doesn't show more than one card details like Afterburner shows.
I have 2 sapphire cards & 2 Asus cards & the BEST OC software in windows is MSI Afterburner.
I already tried & tired with Asus pc doctor, sapphire Trixx, AMD GPU clock tool, AMD over drive.......

If you're using Windows Check out: http://forum.bitcoin.org/index.php?topic=9982

I have EAH5850s and was not able to under clock under 500MHz with MSI Afterburner, but with Clocktweak I can under clock down to 175MHz.  I get 311Mh/s @ 825/175 and temps are between 55-59C. 

You have to enable over clocking in MSI Afterburner. Then only it will let you go below 500 & also u have to go 500, exit Afterburner & open again, now reduce further.

Thanks for the clock tweak link.

Naturally, memory clock wouldn't affect the hashes produced. This is not the memories job to provide calculations. The only thing you benefit from by lowering mem clocks is significant heat reduction produced by your gpu. Also, you may get more stale shares if you're in a pool as your gpu is taking that much longer to process and it tends to miss the last bit or so of a calculation. This is what generally causes a stale/invalid share (false information due to gpu leaving out a bit or two of info).

In my experience, lower mem clock to about 300 Mhz for a relatively stable experience. Doesn't cause too many invalid shares and may reduce your temp by about 8 degrees Celsius depending on your card.

Don't spread bullshit like that, reducing the clock of GDDR ram, ram or any type of chip wouldn't make it "leave out a bit or two" (a FPGA or ASIC might do due to timeing issues but that would moste likely make it fail completly)
Secondly even if it did leave out bits the different mining applications are very unlikely to even accept them as shares and thus report them to the pool...

I am interested into anything that might help to reduce stales. Going up from 269 to 400 did not seem to result in less stales. I will run some more tests.

Good sir, I do say you're quite skilled in the art of Talking Out Your Ass.

Reading your paragraph reminds me of when a woman goes to a mechanic, "he said my muffler bearings were going out, blinker fluid was low, and I somehow made it to the shop with only one transmission and need the second one put back in asap!"