Cards above: standard, RAD audio, USB, fan controller (not connected to SGI), SAS/SATA card, 10GbE ethernet (missing in slot), V12 DCD at bottom right, and the two fan outputs on bottom-right are for optional 2 fans to be mounted on the grill above (on the outside of case).

Big Noctua fan on the left to take air in, and 6 (3x2) on the right (CPU board compartment).

CPU fans viewed from the side. This is how they are factory-mounted on 4x1GHz tezro. I used 2 of them in a row to be stronger. I found contradicting information whether this helps or not. In any case, since this is 4x800 they are not part of factory setup so they are an addition rather than replacement, and also the CPU board/cover is also not full depth so fans partly push air over the cover rather than in it.

Hard disk fan. Not a Noctua, but I did replace it with something. I think I used the original grill in front.

Also installed 4 fans in this area. I think the original had only 3 fans, not sure.

Also installed a fan on the GPU. Since the bottom 2 fans on the front push air into the GPU case, this fan pushes air out of the GPU into the main compartment. This also works wonders for the 10GbE NIC card (first on the line of fan) because when it is working it is generating incredible heat.

Installed cards from the side. From bottom up, the lowest one is SAS/SATA with 4 cables going to the front (currently unconnected), and above that is the fan controller (the small black/gray wires go to fans). This card is not connected to SGI mainboard.