get the x6 for like 90, and a asus m5a78l motherboard for $60, the slower clocked x6 will def beat the a8, if anything go A10 5800k or a athlon ii x4 750k on fm2 socket, if the board takes the 100watt cpus
This is a horrible idea.
You are suggesting he takes a brand-new Asus desktop and replaces the entire motherboard... with a board that is entry-level at best and only uses SATA II and USB 2.0? He'd be downgrading on nearly every level while spending around $165 at minimum. And the CPU performance between the two isn't even that huge:http://www.cpubenchmark.net/cpu.php?cpu=AMD+A8-5500+APUhttp://www.cpubenchmark.net/cpu.php?cpu=AMD+Phenom+II+X6+1055T&id=390
Just the lost speed in the hard drive connections going backward to SATA II on the M5A78 board would be more noticeable than anything gained.
If he goes to a A10-5800k, it looks great on paper, until you realize most of the gains are from the 7660D integrated graphics instead of the 5500's 7560D graphics. The processors are still both quad-core, still both have the same amount of L3 cache and use the same architecture. The clock speed is 500mhz higher on the A10, but is that really worth all the cost and trouble?