SLI low FPS

[drdoom11]

Hi all - 1st time poster here

I believe something is wrong with my current SLI setup

Rig is:
I7 920 @ 3.9ghz 24/7 stable
2x SLI GTX285 at stock clocks using 186.18 WQHL drivers
750watt Corsair PSU
6GB Corsair Dominator 8-8-8-24 1600
EVGA plain vanilla x58 board

Now in most games I am getting extremely high fps, but this was also the case with just 1x GTX 285

Now the game I am using as a benchmark for SLI is Crysis WH -- yes I know this may be a poor choice but from everything I have seen on the internet I should be able to run this game comfortably at only 4x AA and get around 55-60 FPS on enthusiast settings at 1920x1080 (correct me if I’m wrong). I am however getting only high 30s to low 40s in the jungle levels and low-mid 30s in the ice levels. (p.s. in Batman demo with advanced physx and 32xQ I am getting high 30s to low 40s). the game also takes time to get to my normalized FPS after loading (usually it’s a 3-5 min wait of crap FPS before it gets to normal)

Not sure where to begin the diagnosis but maybe I should shed some light on a few things:

I am using older drivers because the newer 190 ones don’t run properly for me

Keeping everything on default setting in the nvidia control panel

Am using dual monitors – but from what I read 180+ drivers default for this and just pick one monitor as the primary SLI one, correct?

My psu is only 750watt but many people are running dual 285s on a corsair – could the problem be here, if so whats the best way to test?

I don’t think its my CPU OC as ive worked on it for a couple weeks to make sure its stable 24/7 at the lowest voltage possible and prime95 temps don’t exceed 65-68 on all four cores during heavy load; however I have read that increasing north bridge voltages helps SLI?

I haven’t OCd my GPUs yet but I don’t think even ocing them past stock speeds will gain me that much more FPS performance; also I didn’t test the 2nd card by itself after I got it and just plugged it into SLI

SORRY for the lengthy post but hopefully someone can she some light on what I should do as next steps to pinpoint the problem

 

[obsidian86]

is the plain vanilla board sli compliant?

 

[drdoom11]

yes by plain vanilla i mean it doesnt have the bells and whistles of their "Classified" board that is a $500 benchmarking board

 

[brett1042002]

With those FPS, it almost sounds like SLI isn't functioning at all. 30-40 fps on enthusiast settings sound like only one card is working. Double check that SLI is enabled in the OS and the bridge connector is properly seated. I'm not sure if you have to enable SLI in game or not... a few games have that option... not sure about Crysis WH.

 

[Mousemonkey]

IIRC when the 285's first came out there were a couple of reviewers who couldn't get them to run in SLi with anythig less than a 1 - 1.2kw PSU.

 

[brett1042002]

Mousemonkey is correct. I used a power supply calculator with your system specs and you are sitting really close to 750w. This is NOT factoring in your OC as well. You might want to look into a higher wattage PSU.

This is probably what is causing the bad performance with SLI trying to work with insufficient power.

 

[drdoom11]

brett1042002 -- SLI is enabled in the nvidia control panel and is being properly recognized - assumes this solves the bridge problem? iirc but i am not at home to confirm, crysis doesnt have that option i believe it just picks it up by itself. i know for example that COD WAW does

mousemonkey -- im starting to think it may be a PSU problem as well. many people on boards with a similar setup are running a minimum of 850 but most with a 1k. i just kind of want to be sure though before shelling out $240 for a new psu

EDIT: also just remembered something. i actually did bump my cards one times to their ftw specs and the game was running at 60-62 for about 10-15 mins but then crashed. again i think this points to the PSU?