I7 Build CM 690 GTX260 SLI Heat Problem

Hello to all:

My Build:

i7 920
2 GTX260's in SLI
Cooler Master CM 690 Nvidia Edition (With all 7 case fan slots filled with stock & Best Buy quality 6x120mm and 1x80mmx15mm)
6 GB Corsair XMS3 DDR3
Corsair TX850 PSU
Asus P6T MOBO
Vista 64
Noctua 1366SE CPU Heatsink

My Problem:

With GPU (and all other fans) at 100%, after about 15 minutes of Furmark stability test GPU's hit 90c or so and crashes system. It also happens when gaming for about 45 minutes.

My Question:

How can I lower my GPU temps?

I'm looking for suggestions from other people who have had success lowering their GPU temps. I know I'm having an airflow path problem due to the massive graphic cards and extra cables from the PSU. The intake fans are at the bottom, front, and sides of the case. The exhaust is the 2 120mm on top and the 120 in the rear. Would swapping all the fans out with higher CFM fans work to overcome the 10.5" graphic cards and extra PSU cables that are blocking the airflow?

I'm open to cutting some holes in my case to add a fan or 2 (the system is loud as h*** already), but the perfect place to mount the fan would require me to cut into the plexiglass or plastic or whatever it's made out of window on the side on the case.

FYI I had CPU heat problems as well. The Noctua CPU cooler cured them by dropping the 100% load temps from 100c to 60c (3.8 Ghz OC) in the Prime95 Torture Test.

Thank you in advance for your replies.

That is exactly how I have my case fans setup.

Like I said I'm using all 120mm Cooler Master stock + dynex Best Buy fans. Would swapping them all out for high cfm fans be enough to cure the problem? I would like some opinions before I drop $120 on 6 top of the cfm line fans.

What case are you using?

The other issue is my MOBO (asus p6t) has me running sli in 2 pci x16 slots right next to each other unlike most 2 card sli/crossfire setups where you have an empty slot in between the cards.

Download this program from EVGA. The EVGA Precision 1.7.1, which will allow you to control the fan speed and also OC your card if you want to.

Read info of it here.
http://www.evga.com/precision/

Best place to download it is here, since you would have to register to EVGA Forum to download it there.
http://downloads.guru3d.com/EVGA-P [...] -2251.html

You have no space at all between the 2 cards? Can you give me the spec of your fans? If nothing else works water cooling might be the solution which is a bit costly.

the cards are practically touching.

@ PsychoSaysDie:

what did you do about your heat? Just upgrade the fans?

Is there watercooling for tri-sli because it's layed out like the top 2 cards in a traditional 3-way sli setup.