Cooling is often overlooked
Besides adding the extra RAM and even the SSD of your choice. These all add extra heat too. SSD is a bit pricey for the larger ones but setting up an array of three of the medium sized units and burning permanent and back up files to DVD. Over clocking and added GPU's with their own fans and it will get pretty hot. A quick solution is to dress your cables, and if need be, useage of posterboard ducting will help to bring in the maximum cooling air and exhaust the hot air any from any intake. Just a small fan would be needed to help boost and establish air flow. The hottest area, the CPU heatsink needs the most cooling. Spacing multiple drives is also critical. Stacking or obstructing air flow can cause failures. RAM would be next unless your GPU is just a heat sink with no fan, then it needs the next coolest air source. Power supplies have their own fan and intakes its air from inside the case, exhausts it out the back near the top. The small fan will be pulling air into the case through a filter near the bottom. Other cards usually don't need much cooling. Overclocked CPU's will also lead to other chips running warmer than normal.
