Sign in with
Sign up | Sign in
Your question

Possible SLI bottleneck?

Last response: in Graphics & Displays
Share
February 7, 2012 2:05:18 AM

Hey so I posted a question before here about the performance of my two GTX 570's. I'll sum it up and say that the two in SLI can't handle BF3 on ultra settings for some reason, the gameplay gets very choppy (and doesn't look like the micro-stuttering videos I've seen on youtube). I thought it was a PSU problem for a while, but now I've been told something different. It was suggested that my CPU is bottlenecking the cards and degrading the performance. I have an i7-2700K (not overclocked) and two EVGA GTX 570's. I'll list my other parts if needed. Thanks!

More about : sli bottleneck

February 7, 2012 2:23:11 AM

Not bottle necked at all that is a great CPU. All software (drivers) up to date?
February 7, 2012 2:47:07 AM

Try it on a different game. If it works fine then you can narrow it down to bf3 and possibly drivers.
The i7 2700k stock wouldnt bottleneck a 7970 xfire let alone 570s.
What is the make and model of your psu
Related resources
February 7, 2012 2:50:21 AM

PSU is an OCZ-ZX850W. Also I have the current stable drivers for the 570's. I read somewhere that disabling hyperthreading on the CPU might fix this problem. I'm going to try that and post the results.
a b Î Nvidia
February 7, 2012 3:00:13 AM

What resolution are you playing at?
February 7, 2012 3:06:12 AM

bottlenecking depends a lot on the game you are playing.

on CPU intensive games like most RPG and RTS , the 2700k stock would be a bottleneck.
on most FPS, the GPU is the biggest bottleneck.

with BF3 as the current most GPU intensive game ever, the 2700k would NOT be a bottleneck with SLI gtx570.
I doubt that it would be a bottleneck even with tri SLI gtx570 !

i doubt that disabling HT will make a difference, but definitely do try that too.

AFAIK, BF3 does not increase performance with 4 cores over two cores at max settings. so a cpu bottleneck is unlikely.

one suggestion is to try disabling all AA and FXAA/MSAA from the options. those settings really hammer the FPS.
with AA, during intensive outdoor scenes, the fps takes a big hit.
February 7, 2012 3:14:28 AM

Bf3 isnt the most gpu intense game out. An i7 2700 is a badass cpu that wouldnt be bottlenecked except in the few cases of badly optimized games.
The power supply op has is badass as well and isnt the problem.
OP have you tried a different game yet?
Even if op wad bottlenecked a bit which is unlikely his setup shouldnt ever get choppy on bf3 aa or not
there is another issue here
February 7, 2012 3:23:59 AM

Dark006 said:
PSU is an OCZ-ZX850W. Also I have the current stable drivers for the 570's. I read somewhere that disabling hyperthreading on the CPU might fix this problem. I'm going to try that and post the results.

Sounds like a plan Im very interesed in the result
February 7, 2012 3:29:28 AM

OMG it worked! I turned off hyperthreading in the BIOS then tried the game. Right away I noticed a difference! I turned on the frames per second and I saw that the frame rate was jumping from 58 to 120, then down to 30, then up to 60. After that I turned on vertical sync and its even better now. I'm only on a single monitor at 1920x1080 by the way.
February 7, 2012 3:42:04 AM

Grats !!!! You didnt even need us after all.
Go have some fun with bf3!!!
February 7, 2012 3:55:16 AM

Ok, now its running great when it stays at 60, but when it drops its like it was before. What causes the framerate to drop? I've seen it go into the low 20's, and I think I even saw it at 12! What should I do to keep it at a constant 60 fps? Oh also each card sits around the mid 80's celsius when playing.
February 7, 2012 4:12:01 AM

Thats fine; setting fan profiles in afterburner can take care of the temps and low mid 80s is normal for a 570 on stock profile.
I was excited for you for a second when you said it was.fixed.
Is it doing this on lower settings as well?
February 7, 2012 4:19:34 AM

I'll have to try tomorrow but I've heard that a single 570 can run the game with AA on. If you have SLI with the same cards AA screws up the frame rate so I'll see how it works with that off.
February 7, 2012 5:27:12 AM

Ok I couldn't wait until tomorrow to find out. I turned vsync off and turned down MSAA to 2x instead of 4. Everything else at max and it runs so smooth now. I get about an average of 100 fps now. I also turned hyperthreading back on and it still works great. I can't believe it was one stupid setting that had me stumped for like a month. Thanks everyone!
February 7, 2012 6:17:24 AM

no prob, good luck!!
sometimes the in game vsync works like *** and the CCC or Nvidia control panel vsync works a bit better
a b Î Nvidia
February 7, 2012 7:00:30 AM

How much Ram are you running?
February 7, 2012 7:19:01 AM

The reason it runs that way is cause the 570 altho a nice card, is limited by its vram. Wouldnt have that issue with a 3gb 580 or the new 7900s.
February 7, 2012 8:07:58 AM

the Vram? you dont need 4 gb of vram to run BF3
a b Î Nvidia
February 7, 2012 8:19:31 AM

Ram makes a difference , when I went up from 4gb to 8gb I no longer got fps drops in BF3 on my 560ti SLI, when i check how much system ram im using in gameplay it goes over 5 GB and thats when it loses fps and its smoothness.
If you want to run BF3 optimal on ultra on 1080, I would recomend more than 4GB of system ram, the difference is huge.
February 7, 2012 8:54:56 AM

3 gb sorry typo. 1280 megs isnt enough to max all the eye candy in BF3. Maybe at 1080p it would be.
February 8, 2012 3:06:18 AM

just a question: can you tell the difference between 2xAA and 4xAA while in gameplay?
i sure cant tell.
!