Underclock 5850 Memory?

[jasonk]

So I have 2x 5830's in another machine, and have the Core turned from 800 to 965Mhz with no stability issues and I keep temps <80.

I just got 2x 5850's and put them in a new rig.  The cards are Saphire Extreme's.

I tried underclocking the memory to 500Mhz.  Instantly froze the entire screen.  So I then rebooted and just tried a small downclock.

I downclocked to 900Mhz.  I looked at my Killawatt meter and was surprised to see the wattage INCREASE by about 30 watts!

Why would it use more power when I'm turning down the memory clock?!?!  Doesn't make any sense.  I reduced the wattage significantly on my 5830's by downclocking the memory.

I'm using MSI afterburner btw.

Any suggestions, appreciated and I just might tip someone.

[Remember remember the 5th of November]

It's because while some cards can do it, the core clock doesnt like the low memory.

Basically downclocking the memory actually does more bad things than it fixes. Keep the mem at stock and deal with it.

[Tukotih]

I have found out that downclocking the memory of my 5850 just worsens things aswell.
My advice is to keep it at stock for now.

[jasonk]

Wow, glad im not alone in this.  I see other people talking about downclocking their 5850's.  I wonder if their wattage has increased as well. 

Amazing that this 58-series cards behave so differently.  5830 loves being downclocked.  5850 screams at you! :p

[redicarus]

I have my 5850 set to 344MHz to get the Mhash boost, never noticed any issues with performance outside of games.

[Basiley]

no puppose.
saves about 5W but cost some MH/s(about 10-40MH/s drop, depend deep of downclocking and GPU model. ~20MH/s for 250 Mhz on 5870, for example).
slightly improve cooling situation for GPU's with badly designed power subsystems[VRM's/IC's without heatsinks and without strong airflow], unsuitable for mining anyway.
if you care about GPU health put extra-fans in case instead. of [better]invest to water-clooling system. for both GPU, GPU subsystem, CPU, mobo chipset, with external radiator[without fan. huge, expensive, but silean and efficent beast]and even with optional heatsink for PSU[relatively rare product]

[jasonk]

no puppose.
saves about 5W but cost some MH/s(about 10-40MH/s drop, depend deep of downclocking and GPU model. ~20MH/s for 250 Mhz on 5870, for example).
slightly improve cooling situation for GPU's with badly designed power subsystems[VRM's/IC's without heatsinks and without strong airflow], unsuitable for mining anyway.
if you care about GPU health put extra-fans in case instead. of [better]invest to water-clooling system. for both GPU, GPU subsystem, CPU, mobo chipset, with external radiator[without fan. huge, expensive, but silean and efficent beast]and even with optional heatsink for PSU[relatively rare product]

Did you read my post?  Your saying it "saves about 5W."  Have you actually MEASURED this?  In my case turning the memory clock down 100Mhz I observed an INCREASE in wattage by about 20-30W!

With my 5830's, turning down the memory clock from 1000Mhz to 175Mhz decreased power consumption by 40-50W (2 cards)!  Not only that but my hash rate went up as well!

I have my 5850 set to 344MHz to get the Mhash boost, never noticed any issues with performance outside of games.

Card model?  OS?  Have you measured wattage of the rig?

[Basiley]

sure i do.
let's explain in "1-2-3" -style then:
its ordinary for 5830[GPU factory overclocked in desperate attempt to compensate limited number of shaders and 1/2 of ROP's), but quite unusual for rest 58xx's, 69xx's.
and more frequent for reference models and yearly altternative-design with 4+1 power subsystems, while newer get 6+1 or somethin like[more stability more power efficency, better temperatures, more reliability/less RMA'ed units for only $1.2 production cost increase].

[Dyaheon]

Afterburner might have some compability problems with underclocking memory, did the same for me.

You could try underclocking while the card is idling so card is at idle clocks, 300MHz memory. Also disconnect extra monitors if you have any, as those raise idle clocks. You could also uninstall afterburner and try Sapphire Trixx.

I recommend doing it, 300 memory makes hashing a bit faster, especially if you turn worksize from 128 to default 256. This is on Phoenix 1.4 with phatk kernel.

I have a Sapphire 5850 Extreme too, and now after I reinstalled Windows it no longer crashes (at least not while doing it idle) when changing from mining clocks (960/375) to game clocks (850/1100)  

I don't have a wattmeter, but at least with my old card (4890) temps dropped when dropping memory speed. Not totally sure if it fits here, as hashing speed increases on this card, but I'd think so.

[Basiley]

Afterburner might have some compability problems with underclocking memory, did the same for me.

You could try underclocking while idling (so card is at idle clocks, 300MHz memory), or uninstall afterburner and get Sapphire Trixx.

I recommend doing it, 300 memory makes hashing a bit faster, especially if you turn worksize from 128 to default 256. Also lowers temps.

I have a Sapphire 5850 Extreme too, and now after I reinstalled Windows it no longer crashes (at least not while doing it idle) when changing from mining clocks (960/375) to game clocks (850/1100) 

try turn off OSD support in Afterburner AND remove "voltage monitoring"(dont affect voltage tweaking but help get rid some artefacts too) - helps in 4/5 cases with MSI AB.

[Adeq]

or try Sapphire TRIXX

[Basiley]

or try Sapphire TRIXX

no offense, but "in general" MSI AB, is lot more stable. only RivaTuner itself was better/more stable. but its not updated too long[for new AMD drivers support].
if you use stable version, not beta.
IMO.

[TETOCONPOLERA]

if you are using afterburner with 5850 extreme, vcore is blocked by default meaning you cant change it, and this may have some incompatibilities when underclocking memory


you'll have to install Trixx latest version if you want 900MHz for core, 300MHz for memory and 1.168v vcore for example...


With stock memory frecuency(1000MHz) I always had about 20~30Mhash/s less than in 300MHz



my configuration is:

HD5850 extreme
Guiminer
flag -v -f10
Catalyst 11.5
SDK 2.1
core 900MHz
mem 300MHz
vcore 1.168
temp 63ºC

getting  360Mhash/s  















with HD6850, afterburner works excellent, but it doesn't with 5850

[Basiley]

"tweaking blocked by default" is new MSI AB default, based on you GPU firmware-stored AMD OverDrive profile.
you can edit[by RBE]you BIOS or just unlock "extreme  overlocking" to bypass that.
thats made to make overclocking more fool-proof, cuz many newbies brick their GPU's that way and then try RMA them.

[RustyShackleford]

This seemed like a good thread to ask; especially because I just finished reading another thread where Baisley appears to be some kind of GPU mastermind


I have a Sapphire 5850 extreme as well, and was using trixx with great success.

However this machine is also my primary computer; and I got a third monitor. Not finding out until later that the 5850 can only support 3+ monitors through native/active DisplayPort (which I had none of); I rigged one of the monitors onto the onboard 4200 (not used for mining; not worth it).

My problem is; trixx will only ever detect/attempt to tweak the settings for the 4200 unless I disable it completely in the bios. I've read that this is a problem with trixx and that there is no fix.

Luckily, MSI afterburner DOES let me select the card to tweak. But it does not let me adjust the vcore and my memory clock seems to adjust itself depending on if i'm mining or not; regardless of what i set it to- as you guys have just described is a problem with MSI AB and Sapphire Extreme 5850.

What i'm wondering is, does anyone have a link or instructions to how do unlock/give MSI the ability to change these settings?

Do I have to uninstall CCC Completely? They seem to 'play nice' provided i'm not trying to use them at the same time. The checkboxes in MSI AB's general tab are already checked; they don't have an effect. Should I bother trying RivaTuner or is it too out of date?

I won't be able to actually attempt any advice until my new heatsink/fan gets here. The blower on my card went out and i'm having to underclock it to hell, with shroud off and 3 fans pointed at it (lost 1/3 of my hasing power) just to keep it below 80.

Thanks

[Dyaheon]

"tweaking blocked by default" is new MSI AB default, based on you GPU firmware-stored AMD OverDrive profile.
you can edit[by RBE]you BIOS or just unlock "extreme  overlocking" to bypass that.
thats made to make overclocking more fool-proof, cuz many newbies brick their GPU's that way and then try RMA them.

Doesn't apply to 5850 Extreme though. It has some custom parts, and Afterburner doesn't yet at least support it. So no voltage changes, even if you unlock extreme overclocking. Afaik only way is trixx, unless bios editing works somehow.

[Basiley]

here handy hotlink http://forums.guru3d.com/showthread.php?s=32db9ad89b774a46a751d0a19df9ed63&t=338906
b careful overclocking. not raise voltage above 1.15V[which barely necessarily, exept if you plan reach insane clocks above 900-950 without water or phase change cooling] until you improve you GPU/PC Case airflow/cooling somewhat and do it slowly[step-by-step. with stability testing["burn-in" mode] in FurMark].
stay sharp and do become Jedi/SuperMan/BitCoin power with you !! and winey pooh -)