The quest was to build a respectable gaming PC, and stay within a reasonable budget. Here's where I am so far.
AMD 555BE: $70
Asus M4EVO w/ ACC (sb750) feature for core unlocking: $100
500GB HD: $40 + Reuse old 320GB: FREE-ISH
Reuse Antec Case from Socket 939 build
8GB OCZ gold DDR3-1333 picked up local:$140
Coolmax 650W PSU $25 from a friend (sold 500W for same price on CL)
22" Viewsonic LCD 1080P monitor $150 (minus $50 for selling my old monitor)
Hyper212 HDT Cooler $20
Now for the part that hurts the most.
I just ordered an ATI 5850: $290FS(that one hurt but I sold my 9800GT for $60 pending delivery of new card)
I then sold my old CPU+MOBO+RAM combo for $60.
So taking into account my used stuff sold, I'm netting out to $640.00.
So I had to hope that I could unlock the possibly available cores on the 555BE, and find out if I have a stable triple or quad core for cheap. Installed the OS without making an unnecessary changes to the BIOS yet, and running the CPU as a stock dual. Win7 installs smooth enough and soon I'm in the BIOS setting up the ACC feature. I boot into Win7 fine and all four cores are unlocked !
Now to test stability at stock voltages. I run PRIME95 and after 30 secs get a failure on the blend tests. Not so reassuring. I then run the separate tests, and voila ... cores run unfettered for over an hour, memory fails after seconds. Time to go fuck with timings. I loosen up a hair and reboot.
Eureka !!! All four cores, + memory stable at 3.2GH per core, and 1333 on the memory after 5+ hours, zero errors. So now I want to push it just a little. Back into the BIOS to use the OC multiplier. We bump to 19X, and up Vcore by .0125. Passes again, and could probably shoot for more but right now I'm happy with my results so far.
3.8GHZ Quad stable
8GB RAM
CPU temps under 55C at 100% load, under 40 Idle
$640 ... woot.