Here is my build:
Mother Board: Gigabyte GA-MA790X-UD4P
RAM: 4GB GEIL Green DDR2-1066 (1.6v)
CPU: AMD Athlon II X2 250 Dual Core Processor Socket AM3 3.0GHZ 45NM 65W
Case: Norco 4220
PSU: Corsair TX750
Drives: 3 1.5TB SATA2, 3 750GB SATA2, & 1 120GB SATA1 (cache drive)
As you can see I made a custom fan plate with 3 140mm fans. I'm not completely satisfied with the performance under parity checks as it is hitting 40-42 on all drives while performing a parity check. Since I'm only at seven disks, I think that further increases the storage density may be require some more powerful fans.
