Fan arrangement for SLI cards

Excellent advice. Thank you. The cards have also been overheating with the side off the case, but I assume that this was possibly because having the case shut and drawing air at a higher speed over the cards would actually cool the cards down faster than being open to the air entirely. Is this correct, or do I possibly have a bigger issue?

The temps of my cards are lower if I have the side fans on my case set as exhausts rather than inlets, as in drawing air away from the cards rather than blowing air onto them.

Standard case design is based upon the window fan blowing in....of course not everyone follows standard practice and every case like this will be different. Considering the fact that all the GTX's I have seen have a ducted exhaust out of the case, I gotta go with having teh side fan blowing in as you prolly have plenty of hot air going out and need some extra "inflow" to balance what's already going out.

Just as you have spent time figuring out the ATIKMDAG issue, I have spent time playing about with the fans on my case which has more than two exit points by the way.

I give a shot at this. Seeing you have 2 side fans and supposing you have a top or back fan my configuration would be:

Both side fans to push air inside and the top/back fan to exhaust the warm air generated.

The cards will generated heat which will be partially eliminated by their own exhausts and the rest or the air will rise. That air will be caught by the back or top fan and exhausted outside. From an airflow point of view it is better to have multiple intakes and fewer faster/bigger exhaust fans.

First off your definition of exit point only being possible at the back is 'odd' as fans move air if the fan is set as an exhaust then the air will exit the case at that point regardless of whether it is at the top, bottom, side, front or back so why would I need instructions? not that there were any.

The default configuration of the Antec 902 has an exhaust out the back and out the top. They have two fans in the front of the case, and room to mount a fan over the video cards on the side panel.

So at what point have I or the OP mentioned a particular make and model of case? and if an Antec 300 or 900 is the same as every other case out there then there is no point in buying one as any case that's cheaper will be the same.

I had a similiar problem with my Thermaltake Xaser III case. I had 2 overclocked MSI GTX 260s in SLI. I put 2 high speed, low noise (they exist) 120s over the card.

I would recommend intake in the front (which also probably helps your HDD as well) and sides, exhaust on the top and the back.

What kind of cpu cooler do you have, what kind of case, and what size/power of fans? These can change the fan setup...

For example, my case actually has 3 120 intakes on the side and 5 exhaust fans (2 80s in front, 2 80s in back, 1 80 on top). It sounds kinda weird but the 3 120s bring in (1 over my ram) about 240 cfm. I noticed that they were so powerful that they pushed air towards my intakes in the front rendering them useless. So I flipped them around as outtakes. Air comes in the side and is pulled out the top, the front, and the back. It dropped my temps around 2 C on my components from the traditional intake front fan set up.

You can also play around with the fan set up and see what does best. To test temps I ran the computer idle for a while and then started prime95 for 30 minutes and checked. I then changed the fan set up and repeated until I got the lowest setup.

  You changed something and saw an improvement, but that's impossible according to some around here.  

I'm pretty sure you were the one who first mentioned the Antec's.