SLI scaling with GTX780s below average

[TEKNIC]

Hi guys I need your help as I am running out of ideas and am not sure what is going on, but first the system specs:

Asus Sabertooth X79
i7 3820 @ 4.3ghz
Corsair Vengeance 32GB @1866mhz
OCZ Vertex 3SSD
Corsair HX850watt
eVGA GTX780s FTW SLI
LG Ultrawide @2560x1080

I am not really new to computers but this has me puzzled the only two games I play right now is SC:2 and BF3 (waiting for 4)...while im gaming in SC:2 I run one card as two is not needed but for BF3 I run two as I play on ultra with 64player servers BUT running two or one is not giving me any fps gains. Running one for sc2 or bf3 with yield in 85-98% gpu usuage running two will yield in 55-73% usage no mattter what but the fps stay at the same level as a single card, and yes vsync is OFF. The cpu usage is around 53-60%. I have included two graphs from in game perfoverlay to show you guys better.

This is BF3 with a single GPU on a 64player server.

- as you can see the gpu and cpu r in a good sync pumping out fps..

This is BF3 in SLI mode on a 64server

- as you can see the CPU is performing well but the GPUS are behind and out of sync which is wierd since now theoretically i should have 180% GPU power.

For further testing I have use each card in single mode and both load ay 90%+ and in SLI mode running synthetic benchmarks the scores are on part unigine heaven @2456 and ungine valley @4340 so Im puzzled if anyone could help or have any ideas id love to hear em. THANKS!

 

[SuB]

you really don't need sli 780's for BF3 64 player servers, but I'll chip in anyway..

BF3 has a built in frame limit cap of 100fps, have you turned that off/turned it up? If there is a limit, then when you use one card it will be working harder than when you have two.

When you switch between 1 card and 2 (completely unnecessary again btw, you might as well just turn on sli, and forget about it and leave it as it is) are you rebooting? Because bf3 can be a fickle bitch and won't always engage the second card if you haven't rebooted.

That said if you're seeing utilisation but lower than on just a single card, then it probably IS using them.

I'd just stick SLi on, forget about changing to one card for other games and make sure you take of the 100fps frame cap on bf3 if you want uber frames, but using them at lower % isn't a bad thing, it means you can run them at lower temps

 

[TEKNIC]

hi and thanks for your reply! i was not aware of the 100fps limit so i will look in to this and i have also left sli on. the thing that bothers me according to the second graph the cards can not keep up in that scene yet they were running only at @55% usage, the fps drops to around 50ish in some areas which is very noticable to me..

 

[SuB]

No worries

Give the fps limit thing a try and let me know how you get on.

 

[TEKNIC]

so i have tinckered around some more with the options u suggested to no success i am still dropping to mid 57ish fps on certain points in maps this is puzzeling with two gyx780s?

 

[SuB]

whats your cpu utilisation like?

 

[TEKNIC]

anywhere from 45-67% so average 2+ cores are always under full load i dont think the i73820 @4.3ghz would bottleneck these two cards? but looking at that second graph the gpu n cpu r way out of sync

whats your cpu utilisation like?