comes out real nice. on dual core Regor,cheap NVS 285 video card and intel SSD consuming <35watt during trading session, absolutely silent.
Here's a intro wiki on building quiet computers I had bookmarked a while back: http://www.wikihow.com/Build-a-Powerful-Quiet-Computer Also this site is dedicated to quiet PCs: http://www.acousticpc.com/
silent pc mentioned above by fellow ET member was also pretty good. a lot of tips on that site. seagate HD's for example. it is true that if you are paranoid about how silent your pc is -then seagate HD is a must,if SSD is not an option or as a backup\archive HD