Ok, I just finished building up a m6400 from parts.
The fastest cpu is an extreme x9300, avg cost is $ 175.00 - $ 200.00, however, I find I like the intel quad cpu, I just paid under $75.00 and works like a champ, scores a full 6.9 on windows performance scale. I installed the best m6500 video card, an ati. Fire pro xhx4f...ati sets a score of 7.1....Now the best hard drive will only score a 5.9 on the scale, but any SSD 3, will show at above 7......Great lil screamer, I have built a few lil screamers for clients that are all super happy with the results. Now bear in mind these are built for engneering, but all have had no complants with games they are running..... Check later in the week, this unit will be listed on ebay seller id roadkingal.