Terrible frame times in SLI

[k33g0rz]

I've been working on this problem for a while and its been seriously troubling me. Basically, I have a 2500k overclocked to 4.6 with 16GB of 1600MHz memory and sli evga 670 ftws. On intensive games like bf4 my frames times seem like they are freezing and then smooth on and off the entire time I play and really ruin the experience. I got a ASUS swift thinking the gsync would fix it but it didn't help as the frame stalls seem to last in the 100s of milliseconds.

My two thoughts are that its because 2500k uses PCI-e 2.0, or that SLI is just terrible and no one mentions it because the nominal frame rate is always high. Please help i've tried basically everything.

motherboard is ASUS P8Z68 -V Pro/gen 3

 

[quilciri]

That is a fairly unique issue. What is your motherboard model?

 

[k33g0rz]

That is a fairly unique issue. What is your motherboard model?

http://www.asus.com/Motherboards/P8Z68V_PROGEN3/

 

[quilciri]

Each card has 8 PCI-e 2.0 lanes to use, which is good for 670's. SLI works great. What other games do you have this issue with? Have you tried returning the 2500k to stock clock speed?

 

[k33g0rz]

Each card has 8 PCI-e 2.0 lanes to use, which is good for 670's. SLI works great. What other games do you have this issue with? Have you tried returning the 2500k to stock clock speed?

It seems to be any game that runs at 99% GPU usage. Older games never do it. I haven't tried to return 2500k to stock clocks but occasionally when i driver update i forget to turn sli on and it seems way smoother even with 70% the framerate.

 

[k33g0rz]

My other theory is that the cards are 2 gb memory and asus swift is 1440p.

 

[quilciri]

I'm running a very similar setup. I have a pair of 2GB 670's pushing a potalion 1440p with the overlord PCB I installed to run at 120hz and a 3570k @ 4.4ghz. & I haven't run into an issue like this.

I do run more demanding games on medium settings to keep the fps around 100. If you're attempting to max out settings on those games, the 2GB sounds like it's the issue. You can try dropping some of the eye candy down a bit and see if you issue clears up as well.

Besides that, if you can tough it out there's DX12 & Mantle - reportedly, they will allow treating multiple GPU's as a single processing unit, and will make cumulative use of RAM in multiple cards. I.E. a pair of 2GB cards will have 4GB available. ,instead of mirroring 2GB.
http://www.tweaktown.com/news/43347/geforce-radeon-gpus-soon-combine-vram-thanks-dx12-mantle/index.html

Essentially, each GPU will each render a portion of the screen instead of trading off rendering full frames like they do now.

Another option is swapping out your 670's for a 390/390X . Dependent on reviews, I may sell my 670's (and one of the 7850's I used before them) and pick this up (and maybe a 4k freesync monitor 😀)

*DX 12 is running in windows 10 TP, but that particular feature isn't running yet.