OK, so let's take the lid off and get inside this SLI system.
To date, every Shuttle chassis has only ever supported a single graphics card, meaning airflow was limited but adequate. By shoe-horning a pair of SLI cards into the same space, there is literally no room for airflow between the two single-slot cards in the Shuttle system.
Shuttle's solution to this predicament is to implement an ingenious heatpipe system to allow for cooling on the two GeForce 6800 GT cards that come bundled with the system. At the top of the case is a fan shroud with two small fans that blow onto the heatsinks below. The heatsinks are connected via a heatpipe to the core on each GeForce 6800 GT.
You can see here how the heatpipe runs diagonally up the card to the heatsinks. The primary reason the SN26P comes supplied with the SLI pair pre-installed is down to the sheer complexity of the design; installation can be done under controlled conditions by skilled workers in Shuttle's assembly plant. Heatpipes are delicate, and can be damaged beyond repair if bent too sharply.
Of course, we aren't short of skilled workers here at bit-tech, and knowing our readers will likely want to pull it apart too, we dove in head first. Removal of the cards is difficult, but you have two options. One is to take apart the heatpipe system while the cards are still in the machine. You can do this by unscrewing the backplate retention mechanism of the nearside card and pulling out that card to enable access to the card on the far side.
The second option involves un-routing all of the cables around the cards and removing both of them 'whole' with the heatpipes attached. Both methods are incredibly fiddly and could well end in tears. It should be obvious that doing this will likely void your warranty, so if you are experiencing problems with your SN26P, talk to your Shuttle reseller first!
The attachment for the cooling solution isn't the best design ever - the screw mechanism could have been designed a little better in our opinion. It involves a rather thin screw thread and a spring loaded screw nut that sits over the top of it. It is possible that you could over tighten the screws and damage the video card if you're not careful. If you are going to take this apart, be sure to take great care when doing so.
In close up, you can see the heatsink attachment to the board. The card in slot 1 has a thermal probe attached to it which reports temperatures back to the motherboard and will initiate a shutdown if things get too hot. Underneath the cooling system is a standard GeForce 6800 GT from Leadtek.