6950 crossfire inquiry

[arnogriffith]

I am planning to do a crossfire setup on my rig. just want to know if 2 6950's unlocked is ok with my amd 955 BE cpu. will it bottleneck my dual gpu setup? and I am using a msi 890gx-g65 mobo that runs 8x 8x on crossfire mode. will my fsp aurum gold 700w be able to handle the load?

is this a good idea? thanks.

any comment is well appreciated.

 

[reprotected]

Your GPU or CPU won't be bottlenecked. The 700w PSU can run the two CrossFire cards assuming they both consume no more than 450 watts at peak. The 8x PCIe limitations will not interfere with the performance (shouldn't at least).

To shorten this up, its a good deal.

 

[bystander]

What is your resolution. If you use a low resolution, the CPU would likely "bottleneck" the GPU's. Not to a point it matters, but GPU's would likely be able to get exceedingly high FPS that the CPU can't keep up with. If you have a high end resolution, then the extra real estate will keep the GPU's busy.

 

[arnogriffith]

thanks for the replies.

i have a monitor with native resolution on 1920x1080 and im plan on adding one after the crossfire setup. and one more question, if i flash the 6950 to 6970 bios, crossfiring both unlocked cards will work just fine right?

 

[bystander]

Yes, the unlocked cards crossfire just like any other.

 

[arnogriffith]

alright all my questions are answered. thank you guys!

resolved!

thanks tom's hardware!

 

[cuecuemore]

Bottlenecking depends on the game, for 90% of them a 955 is just fine, but most everyone is CPU bottlenecked in Starcraft2 and the original Crysis. If you can get you 955 up to 4Ghz or so you should really unlock the potential of those 6950s(good call on those) I know because I'm running an X4 965 and at stock (3.4Ghz) I'm CPU limited in Warhead and a few other games on my Gtx460 SLI setup, but at around 4Ghz or so with my northbridge at about 3000 I'm good to go.

 

[arnogriffith]

how will i notice if im bottlenecked on crysis 1 and starcraft 2?
i can hardly squeeze 35fps using my current video card, (gts 250) on crysis mainstream settings and ultra on sc2. 1 want the 6950 to increase the minumum fps on some games. the game runs fine but on some parts it goes down to less than 30 and i can notice it.
i cannot notice the difference above 50 though. overclocking to 4.0ghz will help solve the low framerate issues right?

 

[bystander]

I believe Crysis is a GPU limited game, so you should gain quite a lot of power with the 6950.

Your system is fine. Any bottlenecks you have will depend on the game, and not be severe. You'll see a nice improvement moving to a 6950. I give it a thumbs up.

Edit: SC2 seems to like a lot of CPU and GPU power. That's one that a CPU overclock should net good improvement, but so would the graphics card.

 

[arnogriffith]

now i am confident with my system and am looking forward on getting those 6950's!
i hope unlocking it will be as easy as pie!

 

[bystander]

I'm using 2 crossfired 6950's unlocked with an i7 920 (the first of the x58 cpu's). It's a huge improvement in Metro 2033, and a nice improvement for Crysis. I do play at 1920x1200, so your single card likely does better than it did for me, but it's not a huge difference (I was probably 12% lower performance than I would be with 1080p).

 

[arnogriffith]

that was nice!
i played crysis warhead on my gts 250 and my videocard almost got killed! right now i am hearing like an electrical humming sound when playing 3d games! i stop playing graphic intensive games until i get those 6950s. now im'a donate the crawling gts250 to my younger brother to replace his 8400gs once i get my hands on those twin beasts! lol!

 

[arnogriffith]

Best answer selected by arnogriffith.

 

[arnogriffith]

I got my hands on two Sapphire 6950s and Crossfire'd it right away. But now I am seeing some issues that I predicted which will happen. One is Micro-stuttering.

Though many are saying most people wont notice it. but in the end, my eyes did. I dont have issues with the FPS as it appears to match benchmarks from different reviews and I really love the performance of my twin 2gb babies (btw I got them both for $460) but microstuttering is sure annoying but tolerable because it only happen to certain parts of my games. and the performance is sure very very uber! lovely!

I have read a few researches about the phenomenon at
http://techreport.com/articles.x/21516

I understand nothing can be done now because microstuttering is still an uphill battle for both green and red camps (just to share 1st hand exp). BTW im using 11.10 drivers for Catalyst.

Another issue is I can't overclock my card even if i try different clocks and voltage! It also doesn't have a bios switch! My bad, i'm so excited i didn't check that out and I can't RMA it now..

Another owner mistake is that my mobo is matx. the two cards sit beside each other and the fan of the top card can hit the back plate of the card below. there is literally no space in between. now the top card idles at 60C+ and reaches 100C at peak using furmark. what i did is to remove the cover of the top card and just leave the pcb with the cooler attached. i didnt expect these cards to be that big. lol!

In the end I'm contented but I know there are still some areas for improvement.. uhmm... drivers? If you have additional tips that might help will be appreciated.