SLI / CrossFire FAQs

[mebuebu]

thank you for the quick response.
I had attempted to monitor the activity with GPU-Z while running a benchmark with and without crossfire. Without crossfire it ran as expected, averaging 50 frames per second and only the first core of my 5970 had activity. But when running with crossfire I was averaging 70 frames per second, but only the 5970 core one showed activity again. This tool claims that I have three GPU's in crossfire. Does crossfire maybe treat all GPU's as one? So even when you attempt to monitor, it will seem like the others won't be working. There has to be an explanation for my increasing frame rates, rather this is the second core been active or all three. I would think our performance would be even greater if all three were active.

 

[Maziar]

Take your 5870 out and test only with 5970 and check if both cores work or not

 

[mebuebu]

I'm sorry it's taken me this long to get back to you. I had tried to monitor activity of my 5970 without the 5870, and I have the same effects as I did disabling crossfire. I did notice the second GPU would stay at 157 MHz for the core clock and 300 MHz for the memory clock,and sometimes the GPU load would go to 6% but only for about 1 second, while the first GPU is at a steady 99 to 100%. Also in the GPUZ under my 5870 ATI crossfire says "disabled" however on the 5970( both GPU's) it says "enabled (3 GPUs)". with crossfire disabled crossfire will read "enabled (2 GPU's)"
with your crossfire setup can you monitor the load of each GPU?

 

[Maziar]

That's really strange,what OS are you using ?

 

[mebuebu]

I am using Windows 7 professional 64-bit.

I just updated to the most recent version. I also tried viewing the GPUz tool while running portal 2 (5760X1080) as I have read it supports crossfireX. But it was still the exact same effect as my other benchmark.I did buy my 5970 on eBay for $450 which I thought was a steal, I'm hoping both cores are functioning properly. Even so crossfire should be working with my 5870. I have tried the two different crossfire bridges that came with each card, I am really lost at this point.

 

[jjtober1]

I would use MSI Afterburner, and set up the overlay to display your GPU usage. You should be able to see your GPU utilization in game that way.

I bought a 5850 at release and a few months ago purchased another one for CF. They worked great on my AM3 board, but when I upgraded to a Z68 windows would randomly not recognize one card. When I switched the cards around that stopped, but I had crashing problems in games so I gave up.

The cards I had were different revisions, and that Z68 didn't seem to like them. It might be your cards just aren't gonna want to play together?

 

[mebuebu]

Again I'm sorry for the long response time. I love MSI afterburner! I have a G 19 Logitech keyboard so I'm able to monitor everything on its LCD while in game. I first tested Skyrim, and only one of my 5970 cores were being used. However I still don't think Skyrim supports crossfire X. Then I tested a plethora of other games and it seems that all my cores are being used at max clock rate and memory ( minus the fact my 5970 bottlenecks my 5870 VRAM, memory and core clock). Thank you all so much for the help! I had one more question, what is a safe temp for my cards? I feel like they are so close in my case they're going to catch fire.

 

[Maziar]

Again I'm sorry for the long response time. I love MSI afterburner! I have a G 19 Logitech keyboard so I'm able to monitor everything on its LCD while in game. I first tested Skyrim, and only one of my 5970 cores were being used. However I still don't think Skyrim supports crossfire X. Then I tested a plethora of other games and it seems that all my cores are being used at max clock rate and memory ( minus the fact my 5970 bottlenecks my 5870 VRAM, memory and core clock). Thank you all so much for the help! I had one more question, what is a safe temp for my cards? I feel like they are so close in my case they're going to catch fire.

When I had a 5970(reference),it ran max @ 85c under load.So I assume anything up to 95c is fine(since you're using another 5970 and a 5870)

 

[herpaderp]

Ummmmmm.... I need some help with AMD APU crossfireing. I just got a family member a new computer with an amd A8 apu 3800 model. now I would like to know which card would be best to hybrid crossfire the APU with, without requiring a 6 or 8 pin power cable, since the computer came with a crappy PSU.

 

[Mousemonkey]

@ herpaderp, Start your own thread.

 

[truegenius]

Q. For maziar, you are a mod but you asked another mod to make it a sticky (in 2007)?

you can include some examples of comparisons of duel/triple sli/cf to equivalent single card config for reference model in performance and power consumption.

 

[nukemaster]

Q. For maziar, you are a mod but you asked another mod to make it a sticky (in 2007)?

He was not a mod back in 2007 😛

 

[Maziar]

@truegenius
Yes I wasn't a mod in 2007,that's why I asked other mods to sticky the thread.
The reason I haven't included performance comparison is because some games don't benefit from 2 or more cards,as a result,in one game 3 cards may perform worse than 2,so adding benchmarks may not be suitable;furthermore,both AMD and Nvidia release hotfixes/new drivers for each game which sometimes make a notable change in benchmarks.

 

[xtreme5]

incredible maziar keep it up!
Really appreciate.

A big thanks to you.

 

[Maziar]

No prob glad you liked it

 

[junitono1]

Can someone help me out on a crossfire issue? I purchased my second 6850 to go crossfire. I plugged it in, CCC recognizes it and recommends to turn on crossfire, unfortunately, I try to select the option to enable it and its grayed out. CCC lets me adjust clock speeds, though. Even speccy is saying that crossfire is disabled, yet see both cards. GPU-Z sees them as well and so does afterburner. Is this a problem? Is crossfire really enabled but speccy just can't recognize it? I know my board supports it (990FXA-UD3) and I have an adequate PSU(Corsair TX750M). I tried uninstalling all the drivers and CCC and reinstalling, even trying out earlier version of CCC, still same problem the grayed out option and speccy saying its disabled.

http://i31.photobucket.com/albums/c356/junitono1/Untitled.jpg

 

[shep66]

Hi,

Can someone tell me the answer to a general question - when in SLI (I have 2 x Asus GTX580's @ 782 MHz) does one card always get hotter than the other?
I'm playing BF3 and one is 98C and the other is 62C. I think these cards are rated to 105C (or is it 95C?) but that seems pretty excessive. On a single GTX480 it never went above 82C.

Thanks

 

[shep66]

1.) air-flow / cross ventilation in your case.
2.) possible different monitor resolutions, what is your monitor set-up.?
3.) does it happen in any other game besides BF3.?

Thanks Malmental. I've started a thread out in the forum.

 

[rahiarain]

what mobo do u suggest for ati 6790 my ram iss ddr2 i am searching for a fine ddr 2 board

 

[Maziar]

DDR2 boards are hard to find.You have to look for (used) P35/P45 boards(some models support DDR2 RAMs)

 

[rahiarain]

DDR2 boards are hard to find.You have to look for (used) P35/P45 boards(some models support DDR2 RAMs)

i have decide for gigabyte ga-x38-ds4 it supports ddr 2.what do you think about the power supply? i am confused in these two
1 : http://www.coolermaster.com/product.php?product_id=6641 and
2 : http://www.coolermaster.com/product.php?product_id=5906&category_id=30
will they support crossfire? gx 550w supports nvidia sli what about crossfire

 

[Maziar]

i have decide for gigabyte ga-x38-ds4 it supports ddr 2.what do you think about the power supply? i am confused in these two
1 : http://www.coolermaster.com/product.php?product_id=6641 and
2 : http://www.coolermaster.com/product.php?product_id=5906&category_id=30
will they support crossfire? gx 550w supports nvidia sli what about crossfire

2 6790's require a more powerful PSU.Consider Corsair HX650/750 instead

 

[rahiarain]

2 6790's require a more powerful PSU.Consider Corsair HX650/750 instead

thanks very much

 

[Maziar]

Better than before I hope

 

[armystutz]

Just hit this, now that I got the new driver for my GPU 3DMarkVantage worked. thought my driver was up to date and it was pissing me off but I guess it wasn't, made me feel stupid. score is pretty good considering I built this PC for about $700
the "High" test scored 13,681 GPU 13,841 CPU 12,838
I think I'll buy another one of these cards and run SLI since they are only 227,000 KRW here in Yongsan
Was using a GTX 260 in it but I was only scoring about 8700 on the 3D Mark Vantage and I recently switched to the ASUS ENGTX 560Ti and now im scoring up in mid 13k awesome
http://3dmark.com/3dmv/3965741