Building a 6990 Rig - Operating System

[eleuthria]

I'm building a rig with the immediate goal of running just a single 6990, and then adding on another 6990 in a month or two.

What will give me the best results for Mhash/sec currently, Linux or Windows?  Which distro of Linux or version of Windows should I load onto it?


Building it with the following:
  Case: Cooler Master HAF 932
  Motherboard: MSI 870-G45 AMD
  CPU: AMD Sempron 140
  RAM: 2 gigs
  HD: 16 gigabyte solid state drive
  Power Supply: 1000 watt

[grndzero]

I think once the nuances of drivers and SDK versions are worked out, the performances on each OS are roughly the same barring anything else. So it comes down to preference and what you intend on doing with it and what you're comfortable with.

If it's a dedicated mining machine then Linux is good for setting up and letting it go.
If it's not a dedicated machine or you want to tweak every little aspect of the card then you need x64 Windows.

[eleuthria]

Can you elaborate on "tweaking every little aspect"?

I know I'm definitely going to underclock the memory speed to suppress the power drain as much as possible, and play with the core speed to find a sweet spot for Mhash/W vs Mhash/sec.

[grndzero]

Core and mem speeds can be tweaked from Linux. If you want to change anything beyond that such as voltage you need the Windows programs that do that since they don't exist on Linux.

Ubuntu is a pretty popular distribution and quite a few people use it here so it would be easy to get help.

There is a thread here with some nice instructions for getting it set up http://bitcointalk.org/index.php?topic=3359.msg47174#msg47174

It doesn't look like the ppa:ubuntu-x-swat/x-updates repository with the update Radeon drivers is not available anymore, it gives me errors when I try to update. The radeon drivers in Ubuntu 11.04 are newer than those but 11.04 is still beta (which might not be a problem). I haven't tried upgrading yet.

EDIT: It looks like the packages can be downloaded directly here if the apt-source isn't available. https://launchpad.net/~ubuntu-x-swat/+archive/x-updates/+sourcepub/1398782/+listing-archive-extra

OR possibly get the updated packages from the 11.04 version.

[Syke]

Linux is not an option for a 6990 rig. ATI has not released the Linux drivers yet.

[TenthReality]

Linux is not an option for a 6990 rig. ATI has not released the Linux drivers yet.

Pretty damn important piece of information to know.  ATI have a timeline on the drivers?

[eleuthria]

So since it sounds like Linux is currently out of the question (or at least not optimal), which version of Windows should I use (if it matters)?

[Syke]

I threw Win7/32bit on my box and it is slow as a dog. I hope 64bit is better.

[Littleshop]

I have both windows 7 64 bit machines and windows xp 32 bit machines.  The 5870's do the same in both machines, 330k at 900mhz clock.  I use the latest stream as I could NOT get 2.1 to work. 

The windows 7 64 bit machines run smooth an can be used for something else, the XP machines feel doggy but produce the same hash rates.  If you are not using it other then mining it does not seem to matter.

[jks007]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

[yomi]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

How did you unlock the 6950? Did you do it in ubuntu or in Windows?

(I have a 5850 I would like to unlock too)

Thanks!

[rezin777]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

How did you unlock the 6950? Did you do it in ubuntu or in Windows?

(I have a 5850 I would like to unlock too)

Thanks!

There are overclocking programs out there to unlock the 6950. Afterburner may be one of them (I'm not sure, I don't own a 6950). You can not unlock a 5850 to equal a 5870.

[Syke]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

What's the hashrate on the 6990, and which miner?

[jks007]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

How did you unlock the 6950? Did you do it in ubuntu or in Windows?

(I have a 5850 I would like to unlock too)

Thanks!

6950 reference is pretty easy to unlock with atiwinflash + the RBE tool (takes about 5mins), I did it under windows, just get the bios image using atiwinflash, load it up with the RBE, go to the additional features tab where you then select unlock 6970 shaders, load it back on on the 6950 with atiwinflash(unlock bios if you have to) restart , done.

I assume you mean 6950, as I dont have experience with 5850.

[jks007]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

What's the hashrate on the 6990, and which miner?

I'm using poclbm and getting a hash rate of 310 Mhash on the 6990 with the bios in default setting, on the unlocked 6970 I get around 320 Mhash.
I've used this guide by roulo http://bitcointalk.org/index.php?topic=3359.msg47174#msg47174
And then continuing with this guide by humble http://bitcointalk.org/index.php?topic=3356.msg47489#msg47489

I used 11.3 Catalyst (latest available) with the latest APP for linux available.
Disabled autoupdates through update manager (after finishing installation) (caused problems after an autoupdate)

in order to overclock/underclock the memory I used AMDOverdriveCtrl
http://sourceforge.net/projects/amdovdrvctrl/

launched 1 for each gpu using (AMDOverdrive ctril -i <adapter num given by the --help flag>) in the bash.

My only gripe is that on a seperate (everyday usage) rig my other 6970 gets 345 Mhash @ 900Mhz on windows where I can push it further (than 840Mhz  on linux) with MSI Afterburner, and lower mem clock lower than 725Mhz (linux).

So if I can sort out the little problems in windows or get hold of a nice alternative mining software, I'm pretty sure my hashing rate would go up.

[proudhon]

I just discovered bitcoin via a philosophy podcast (of all places).  I love the idea of a decentralized form of money!  I happen to have a 6990 that I can employ in mining 24/7 and I'm just wondering if somebody can help me assess how many bitcoins per month this would yield.

[bitjet]

I just discovered bitcoin via a philosophy podcast (of all places).  I love the idea of a decentralized form of money!  I happen to have a 6990 that I can employ in mining 24/7 and I'm just wondering if somebody can help me assess how many bitcoins per month this would yield.

depends on the level of difficulty. currently you could probably expect 6-9btc per day from a single 6990 mining in a pool.

[proudhon]

I'm getting between 450 and 500 mhash/s with my single 6990 in W7x64 with the latest Catalyst drivers and the latest AMD SDK and using poclbm-gui.  Anyone have any tips on how to improve my hashrate?  Should I have added anything to the 'Extra flags' box of poclbm-gui?

I don't know if I'm doing this right, but in poclbm-gui I have two tabs open - one for each gpu of the 6990.  Each gpu is mining with deepbit.  Is there a way to just have tab, but have that tab using both gpus?

[bitminer]

I don't know if I'm doing this right, but in poclbm-gui I have two tabs open - one for each gpu of the 6990.  Each gpu is mining with deepbit.  Is there a way to just have tab, but have that tab using both gpus?

No, you have to open 2 tabs.

[proudhon]

I don't know if I'm doing this right, but in poclbm-gui I have two tabs open - one for each gpu of the 6990.  Each gpu is mining with deepbit.  Is there a way to just have tab, but have that tab using both gpus?

No, you have to open 2 tabs.

Ok, thanks.

[mrb]

Linux is not an option for a 6990 rig. ATI has not released the Linux drivers yet.

Pretty damn important piece of information to know.

As stated numerous times, this is untrue. The 6990 is fully supported under Linux by the Catalyst 11.3 driver. I am mining with it!

The confusion comes from AMD's website that only lists Windows 7 drivers when selecting "HD 6990". Select "HD 6xxx" instead.

[Syke]

Linux is not an option for a 6990 rig. ATI has not released the Linux drivers yet.

Pretty damn important piece of information to know.

As stated numerous times, this is untrue. The 6990 is fully supported under Linux by the Catalyst 11.3 driver. I am mining with it!

The confusion comes from AMD's website that only lists Windows 7 drivers when selecting "HD 6990". Select "HD 6xxx" instead.

So if I go to http://support.amd.com/us/gpudownload/Pages/index.aspx and select HD 6990 I see only Windows drivers. That's not fully supported, now is it? There are significant problems with the 11.3 driver, especially relating to OpenCL. So unless you plan on Open Sourcing your CAL miner, stop telling people that 11.3 is "fully supported".

[mrb]

I replied to you who stated "ATI has not released the Linux drivers yet" which is untrue:
- 11.3 was fixed to support the HD 6990 (previously aticonfig displayed "no supported device")
- There are people mining successfully, with poclbm and Diablo's miner (not only my miner), on Linux, on the HD 6990.

A glitch on the website doesn't mean it is unsupported. Like I said, select "HD 6xxx". You and I can argue about the meaning of "fully supported", but what I want to convey is that it actually works. Again, people are mining with it. You may want to try poclbm which runs faster than Dialbo's miner on the 6990.

[Veldy]

I'm getting between 450 and 500 mhash/s with my single 6990 in W7x64 with the latest Catalyst drivers and the latest AMD SDK and using poclbm-gui.  Anyone have any tips on how to improve my hashrate?  Should I have added anything to the 'Extra flags' box of poclbm-gui?

Pass -v -w 128 to your miner and you will see your 6990 increase without a doubt.  I am getting 333Mhash/s with my 6970 just installed yesterday.  I am not overclocking or underclocking anything as I don't want to generate more heat [so I left voltage locked] and changing clock speed for memory or core in either direction affected hash rate negatively.

I don't know if I'm doing this right, but in poclbm-gui I have two tabs open - one for each gpu of the 6990.  Each gpu is mining with deepbit.  Is there a way to just have tab, but have that tab using both gpus?

Did you setup the cards with the crossfire cable and setup crossfire in the motherboard BIOS?

[proudhon]

I'm getting between 450 and 500 mhash/s with my single 6990 in W7x64 with the latest Catalyst drivers and the latest AMD SDK and using poclbm-gui.  Anyone have any tips on how to improve my hashrate?  Should I have added anything to the 'Extra flags' box of poclbm-gui?

Pass -v -w 128 to your miner and you will see your 6990 increase without a doubt.  I am getting 333Mhash/s with my 6970 just installed yesterday.  I am not overclocking or underclocking anything as I don't want to generate more heat [so I left voltage locked] and changing clock speed for memory or core in either direction affected hash rate negatively.

I don't know if I'm doing this right, but in poclbm-gui I have two tabs open - one for each gpu of the 6990.  Each gpu is mining with deepbit.  Is there a way to just have tab, but have that tab using both gpus?

Did you setup the cards with the crossfire cable and setup crossfire in the motherboard BIOS?

Thank you.  Adding "-v -w 128" definitely made a difference.  I just have a single 6990, and a single 6990 has two GPUs, so I don't think I need to do anything with crossfire.

[Veldy]

Ah, for some reason I thought you built a rig with two 6990.  I looked at getting the 6990, but it won't fit in my existing case (the 6970 leaves about 1/4" to spare and creative cable management).  From what I have read, they had to do some trade offs to get the dual GPU to fit on that board, so you won't see double what the 6970 puts out in general, but it is cheaper than two 6970's in cross fire, so count your bitcoins one way or the other

[Syke]

Thank you.  Adding "-v -w 128" definitely made a difference.  I just have a single 6990, and a single 6990 has two GPUs, so I don't think I need to do anything with crossfire.

Can you get over 550 mhps?

[Veldy]

Thank you.  Adding "-v -w 128" definitely made a difference.  I just have a single 6990, and a single 6990 has two GPUs, so I don't think I need to do anything with crossfire.

Can you get over 550 mhps?

I am pulling 333Mhash/s with my 6970 for reference.  The 6990 is pretty much the same GPU, but two of them on the same board.  I also am curious what he is getting with the 6990.

[proudhon]

Thank you.  Adding "-v -w 128" definitely made a difference.  I just have a single 6990, and a single 6990 has two GPUs, so I don't think I need to do anything with crossfire.

Can you get over 550 mhps?

Since I added "-v -w 128 -f0" I've been getting ~620 mhps.  I've also noticed times when deepbit reports that I'm getting >700 mhps.  I haven't logged onto the mining machine to see if poclbm-gui reports the same, so I don't know if deepbit is misreporting my mhps.  





In this last screenshot you can see on the left some occasions where deepbit reports less than 600 mhps, but those were spans of time when I was actually working on the mining machine, and even moving the mouse around will sometimes drop the hash rate by 50 mhps; and I was using Internet Explorer and adjusting fan speeds.  If I leave the machine alone, it settles in at about 620 mhps.

My hunch is that deepbit is misreporting my hash rate.  There have been occasions when, from my laptop, I've seen deepbit report that I'm getting ~550 mhps, but at the same time, or over the same period of time, poclbm-gui reports that I'm getting ~620 mhps.  I'm not sure what to make of that.

[[Tycho]]

Since I added "-v -w 128 -f0" I've been getting ~620 mhps.  I've also noticed times when deepbit reports that I'm getting >700 mhps.  I haven't logged onto the mining machine to see if poclbm-gui reports the same, so I don't know if deepbit is misreporting my mhps. 

Deepbit can't see your exact mining speed, those numbers are guesstimated from number of submitted shares.
You can be more lucky in one minute and less lucky in another, but overall it's pretty close to real value.
Sometimes you may find a run of many shares in a few seconds - then the number on luck meter will be higher.

You can open advanced settings page and increase averaging window from 7 minutes to 30 minutes and this reported speed will be more precise. But since it depends on luck, it's not guaranted to be 100% accurate.

On the other hand, your reward depends on the speed reported by "luck meter", and not the real hashrate, because the number of submitted shares is what you get your money for :)

Looking at numbers in your history column i can say that your actual speed is ~622 MH/s, because those are calculated for all the block's lenght and thus more accurate.

EDIT: and you forgot to erase your login name in the upper right corner :)

[proudhon]

Since I added "-v -w 128 -f0" I've been getting ~620 mhps.  I've also noticed times when deepbit reports that I'm getting >700 mhps.  I haven't logged onto the mining machine to see if poclbm-gui reports the same, so I don't know if deepbit is misreporting my mhps. 

Deepbit can't see your exact mining speed, those numbers are guesstimated from number of submitted shares.
You can be more lucky in one minute and less lucky in another, but overall it's pretty close to real value.
Sometimes you may find a run of many shares in a few seconds - then the number on luck meter will be higher.

You can open advanced settings page and increase averaging window from 7 minutes to 30 minutes and this reported speed will be more precise. But since it depends on luck, it's not guaranted to be 100% accurate.

On the other hand, your reward depends on the speed, reported by "luck meter", and not the real hashrate, because the number of submitted shares is what you get your money for

Thanks.  That's good to know.

[ghost]

I just set up a dual 6990 miner and I'm not having much luck with performance. I've tried both Ubuntu 10.10 and 11.04. Currently using the 11.3 Catalyst drivers and 2.3 stream sdk.

Here are my current rates running poclbm:

Card 1 - core is at just over 300khashes/s, core 2 won't run (Verification failed, check hardware!)

Card 2 - just under 90khases/s, though I've seen this card exceed 200k per core

I may have to give Windows a shot until there is better driver support for the 6990s.

[proudhon]

I just set up a dual 6990 miner and I'm not having much luck with performance. I've tried both Ubuntu 10.10 and 11.04. Currently using the 11.3 Catalyst drivers and 2.3 stream sdk.

Here are my current rates running poclbm:

Card 1 - core is at just over 300khashes/s, core 2 won't run (Verification failed, check hardware!)

Card 2 - just under 90khases/s, though I've seen this card exceed 200k per core

I may have to give Windows a shot until there is better driver support for the 6990s.

I advise you go with Windows.  Much less of a headache.  I'm using 11.3 Catalyst drivers and Stream SDK 2.4 and at stock clocks I'm getting 307.5 Mh/s on each core.

[bahnfire]

I have a dual card (4 core) 6990 system going 24/7. I am seeing between 1200-1400MH/s on deepbit. I am running Windows 7 x84, 4GB RAM, 2 unmatched 6990s (XFX and a Sapphire), and a watercooling kit.

[chadqberry]

@bahnfire or anyone else who can help:
What is your setup with the dual 6990's w/ Win 7?  If you would please give me some details as I'm trying to get mine where it should be.
I'm also using Windows 7 with Dual 6990's.  Currently I have them in crossfireX, using the latest poclbm and catalyst 11.5.  I've played around with several clock speeds, etc but nothing really make a lot of difference.
I have all 4 cores mining, but (3) are mining at 325mhs while the 4th is only at 100mhs.  Can anyone offer me some advice?
I'm using -v -w 128 --platform=0 switches.
(without --platform=0 for some reason everytime I started the 2nd core the whole machine would lock up)
Thanks

[citizen]

@bahnfire or anyone else who can help:
What is your setup with the dual 6990's w/ Win 7?  If you would please give me some details as I'm trying to get mine where it should be.
I'm also using Windows 7 with Dual 6990's.  Currently I have them in crossfireX, using the latest poclbm and catalyst 11.5.  I've played around with several clock speeds, etc but nothing really make a lot of difference.
I have all 4 cores mining, but (3) are mining at 325mhs while the 4th is only at 100mhs.  Can anyone offer me some advice?
I'm using -v -w 128 --platform=0 switches.
(without --platform=0 for some reason everytime I started the 2nd core the whole machine would lock up)
Thanks

I was running 2 6990s in a machine with the sames results.  Cores 1-3 would work fine - getting about 320 mhash/s.  Core 4 would see around 100 mhash/s.  I too was using poclbm.  Has anyone gotten 2 6990s fully working in one machine with windows?  If so, could you tell us the details?

[bcpokey]

It's funny how this thread turned into a 6990 thread rather than an OS thread.

I had a quick question about the starting topic though heh. How much more stable is linux compared to windows in general? I'm currently running some dedicated mining boxes on windows and I am currently still working out the kinks of heat and whatnot, so I get about 1 crash per day.
Is that because of windows and I'd get better results in linux, or is my thermal / overclock too high and it's my fault? (running 3x 5870s in one box unspaced, OC'd to 975MHz, top card can getupwards of 90C, but I've also had occasional crashes in a spaced rig with temps closer to 80C).

[markietalkie]

Mining with one 6990, factory setting @GPU 830 MHZ, Memory 1250 MHz, 1.120V

Linuxcoin, Pheonix with poclbm

DEVICE 0: VECTORS AGGRESION=13 WORKSIZE=128 BFI_INT reporting 334Mhash/sec
DEVICE 1: VECTORS AGGRESION=13 WORKSIZE=128 BFI_INT reporting 323Mhash/sec

http://50.45.128.27/uimg.php?u=markietalkie



I hope I'm doing this right. If I'm doing it wrong, any advice would be greatly appreciated.

[655321]

I have a single 6970. In linux with worksize 128 and -v and overclocked to 950mhz, i only got 352Mhash.

Now I'm mining in Windows 7, with -w 128 -v and the like, overclocked to 950mhz and I am getting 412Mhash.

Go for Windows. The drivers are better and faster when it comes to the ATI cards.

[Wepp]

As others have stated, it really is a matter of personal preference. Or money, if you don't want to spend $$$ on Microsoft.
Personally, I'm using W7 x64 because this is my main personal computer. I'm getting a steady 375-385 MH/s per GPU with mild overclocking. I did have difficulty trying to reduce the Memory Clock, so I have that set at 1000Mhz and the Core Clock at 900Mhz.

If you do decide to go w/ Windows, I recommend using MSI Afterburner (it does work on non-MSI cards):
http://event.msi.com/vga/afterburner/download.htm

I use the latest Beta version with success.
https://i.imgur.com/yJSH0.png

Also, the fan on the 6990's is LOUD. Very loud. I mean it's so loud that I can hear it next door in my neighbor's apartment...
They also run quite hot. I fiddled quite a bit with the fan settings in MSI Afterburner to get the fan speed as low as possible. If you do not do this, and just let the hardware set the fan speed automatically, it will alternate between high and low speeds and probably annoy the piss out of you. Here are the settings I use to keep the fan at a very stable 65-67%:

https://i.imgur.com/MF4wD.png


I keep my interior room temperature around 75ºF. Your conditions may vary.

[goldcd]

Just to chip in.
I'm currently running 2x6990 cards.
Bought these with some very old bitcoins I had, so I'm looking at this as a free 'ninja game system' that make make me some money.

Firstly I'm running my two 6990 in crossfire mode under win7-64bit. I believe I might do better turning the crossfire off, but that involves dummy VGA plugs and my first attempt at those didn't work.

Two tips I have to give out to my fellow 2x6990 user:
1) Use MSI afterburner.
At core voltage I can get the Clock up 20 to 850 and reduce the memory clock down to 625. This not only gets the hash rate up a little, but reduces the power consumption down by well over 100W
2) Assign all processes to the same core on your CPU. E.g. Create a .bat file as follows:
"
start /affinity 1 /min poclbm.exe -d0 -w256 -f60 --host=mining.bitcoin.cz --port=8332 --user=?.?--pass=?
start /affinity 1 /min poclbm.exe -d1 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
start /affinity 1 /min poclbm.exe -d2 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
start /affinity 1 /min poclbm.exe -d3 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
Just underclocking the memory and assigning to one core got my power consumption down from over 900W, to just over 700W

I'm not for one moment suggesting this is the 'best' configuration, but it pulls in around 340 a core, which seems reasonably respectable.

[Coma]

I suggest LinuxCoin all the way.
Free, from pendrive, up and running in minutes.

Then if you want to OC, edit your cards BIOS in 15 minutes.

[darkpandora]

you can use atioverdrivectrl in ubuntu to set your 6990 clock to 1000,150. you get 850 Mhash/s

[Coinbuck @ BTCLot]

I'm running a 6990 + 2 6950(unlocked) in Ubuntu 10.04 just fine with 11.3....

How did you unlock the 6950? Did you do it in ubuntu or in Windows?

(I have a 5850 I would like to unlock too)

Thanks!

There are overclocking programs out there to unlock the 6950. Afterburner may be one of them (I'm not sure, I don't own a 6950). You can not unlock a 5850 to equal a 5870.

However you can flash a 5850 into a 5870 but it's completly useless since that will not unlock the shaders.

Regards,

[Departure]

Just to add some of my small experience with the 6990's using Windows, I set the clocks 920/840 and get just under 400 MH/s per core(just under 800MH/s per card) with fans set at a constant 90% the GPUs get around 70-75c except for GPU2 which is at 81c. I noticed when going lower with mem clock it actually gains heat (1-2 degree's). Also these is a switch near the crossfire port that will turn stock 830/1250 into 880/1250, I used afterburner to get the 920/840. Also something to think about is that you can not under clock memory less than 100mhz of core clocks(you can visually do it but the effectivness is zero and will reset your mem clock back 1250, at least in linux anyway). I did get over 405 MH/s by setting the clocks to 940/840 but didn't want the extra heat or didn't want to increase fan speeds above 90%. The temps are stable and barely move. I used Phoenix Riser with "vectors" "13 aggression" and use the "BFI_INT" as extra flags. I still need to tinker around with the fan speeds to see what effect it has when lowering them, but im happy with 2 x 6990's(I use to have 3 but got too hot under linux) which produces just under 1600 MH/s

[ixfinito]

you can use atioverdrivectrl in ubuntu to set your 6990 clock to 1000,150. you get 850 Mhash/s

Hi Darkpandora,

Can you share with us how you managed to change the memory clock speeds in your 6990? I'm currently stuck at 1250 and nothing I do seems to untangle it. Please help if you can, thanks!

Regards,

Forsythe

[ixfinito]

Just to add some of my small experience with the 6990's using Windows, I set the clocks 920/840 and get just under 400 MH/s per core(just under 800MH/s per card) with fans set at a constant 90% the GPUs get around 70-75c except for GPU2 which is at 81c. I noticed when going lower with mem clock it actually gains heat (1-2 degree's). Also these is a switch near the crossfire port that will turn stock 830/1250 into 880/1250, I used afterburner to get the 920/840. Also something to think about is that you can not under clock memory less than 100mhz of core clocks(you can visually do it but the effectivness is zero and will reset your mem clock back 1250, at least in linux anyway). I did get over 405 MH/s by setting the clocks to 940/840 but didn't want the extra heat or didn't want to increase fan speeds above 90%. The temps are stable and barely move. I used Phoenix Riser with "vectors" "13 aggression" and use the "BFI_INT" as extra flags. I still need to tinker around with the fan speeds to see what effect it has when lowering them, but im happy with 2 x 6990's(I use to have 3 but got too hot under linux) which produces just under 1600 MH/s

Hey dude, nice workaround, I'm having trouble with my 3x6990's temperatures. I have one question, you mention that underclocking more than 100mhz of core clocks will default to 1250, so how did you manage to get to 840 in linux? or did you end up using windows and afterburner for good? thanks!

[nebiki]

Just to add some of my small experience with the 6990's using Windows, I set the clocks 920/840 and get just under 400 MH/s per core(just under 800MH/s per card) with fans set at a constant 90% the GPUs get around 70-75c except for GPU2 which is at 81c. I noticed when going lower with mem clock it actually gains heat (1-2 degree's). Also these is a switch near the crossfire port that will turn stock 830/1250 into 880/1250, I used afterburner to get the 920/840. Also something to think about is that you can not under clock memory less than 100mhz of core clocks(you can visually do it but the effectivness is zero and will reset your mem clock back 1250, at least in linux anyway). I did get over 405 MH/s by setting the clocks to 940/840 but didn't want the extra heat or didn't want to increase fan speeds above 90%. The temps are stable and barely move. I used Phoenix Riser with "vectors" "13 aggression" and use the "BFI_INT" as extra flags. I still need to tinker around with the fan speeds to see what effect it has when lowering them, but im happy with 2 x 6990's(I use to have 3 but got too hot under linux) which produces just under 1600 MH/s

Hey dude, nice workaround, I'm having trouble with my 3x6990's temperatures. I have one question, you mention that underclocking more than 100mhz of core clocks will default to 1250, so how did you manage to get to 840 in linux? or did you end up using windows and afterburner for good? thanks!

edit: anyhow, thanks for the input. maybe 6950s are the same, because i can't get my memory clock down. gonna try going for coreclock-100MHz now.

edit²: nope, i can't underclock my memory.

[Departure]

Just to add some of my small experience with the 6990's using Windows, I set the clocks 920/840 and get just under 400 MH/s per core(just under 800MH/s per card) with fans set at a constant 90% the GPUs get around 70-75c except for GPU2 which is at 81c. I noticed when going lower with mem clock it actually gains heat (1-2 degree's). Also these is a switch near the crossfire port that will turn stock 830/1250 into 880/1250, I used afterburner to get the 920/840. Also something to think about is that you can not under clock memory less than 100mhz of core clocks(you can visually do it but the effectivness is zero and will reset your mem clock back 1250, at least in linux anyway). I did get over 405 MH/s by setting the clocks to 940/840 but didn't want the extra heat or didn't want to increase fan speeds above 90%. The temps are stable and barely move. I used Phoenix Riser with "vectors" "13 aggression" and use the "BFI_INT" as extra flags. I still need to tinker around with the fan speeds to see what effect it has when lowering them, but im happy with 2 x 6990's(I use to have 3 but got too hot under linux) which produces just under 1600 MH/s

Hey dude, nice workaround, I'm having trouble with my 3x6990's temperatures. I have one question, you mention that underclocking more than 100mhz of core clocks will default to 1250, so how did you manage to get to 840 in linux? or did you end up using windows and afterburner for good? thanks!

When I said that I meant memory clock can not be more than 100mhz below core clock... for example I upped my core clock to 940 meaning that the lowest I can go on mem clock is 840, If I how ever had 960 core clock and 840 mem clock, the mem clock will default back to 1250 due to being 110mhz below core clock. Yeah my 3 6990's got hot very hot so I removed 1 and run with 2 on windows using afterburn, windows structure only allows 4 instances of the driver to be loaded at the same time, something do with opencl, So no good for 3 x 6990(6 GPU's). If anyone does get 3 cards running at a decent hash rate(2000 MH/s + ) and keep the cards cool, then I will go back to linux, until then Im happy with 2 cards running at 1600 MH/s

[liuk03]

Just to chip in.
I'm currently running 2x6990 cards.
Bought these with some very old bitcoins I had, so I'm looking at this as a free 'ninja game system' that make make me some money.

Firstly I'm running my two 6990 in crossfire mode under win7-64bit. I believe I might do better turning the crossfire off, but that involves dummy VGA plugs and my first attempt at those didn't work.

Two tips I have to give out to my fellow 2x6990 user:
1) Use MSI afterburner.
At core voltage I can get the Clock up 20 to 850 and reduce the memory clock down to 625. This not only gets the hash rate up a little, but reduces the power consumption down by well over 100W
2) Assign all processes to the same core on your CPU. E.g. Create a .bat file as follows:
"
start /affinity 1 /min poclbm.exe -d0 -w256 -f60 --host=mining.bitcoin.cz --port=8332 --user=?.?--pass=?
start /affinity 1 /min poclbm.exe -d1 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
start /affinity 1 /min poclbm.exe -d2 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
start /affinity 1 /min poclbm.exe -d3 -w256 -f0 --host=mining.bitcoin.cz --port=8332 --user=?.? --pass=?
Just underclocking the memory and assigning to one core got my power consumption down from over 900W, to just over 700W

I'm not for one moment suggesting this is the 'best' configuration, but it pulls in around 340 a core, which seems reasonably respectable.

hi goldcd, i have the same setting, 2x6990 on w7 and i overclock with MSIafterburner at 900MHz but when i try to underclock the memory 779MHz is the lower value that i can set, if i try to set 625MHz the memory clock go in the default valute 1250MHz, why i can't put 625?