It's been with us a venerable amount of time, but it seems as if the curtain is beginning to close on AMD's K8 micro architecture. AMD launched its Athlon 64 X2 6400+ Black Edition shortly before the announcement of the quad-core Barcelona/Phenom so it's safe to say that this 3.2GHz CPU is the final hurrah for the K8 core. To add to the excitement we're claiming this review as a global exclusive because AMD hasn't sent out review samples of any desktop processor in living memory - our last sample was an X2 5000+ - so we took the bold and radical step of buying a retail X2 6400+ from Overclockers.
As we're a paying customer we'd like to make a few points about this retail boxed processor. First it comes without a heatsink/fan and secondly Overclockers says that it will supply a copy of Call of Juarez ‘while stocks last'. We didn't get the game so we assume that stocks didn't last long. Thirdly we have absolutely no idea what the Black Edition monicker is all about. It's a processor in a box. End of story.
So what's new in the 6400+? There's a comprehensive table of X2 processors on 30_118_9485_13041%5E13076 00.html AMD's website so let's quickly pick out the key features. The 6400+ is the only 3.2GHz CPU in the range with 1MB of L2 cache on each core. The fastest models - 5400+ and upwards use the older 90nm fabrication process while models from 5000+ and slower use either 90nm or 65nm. This is significant because the 90nm models have a TDP of 89W while the 65nm processors are only rated at 65W, which suggests that the 125W 6400+ is running at the limits of the K8 architecture on 90nm.
It was a toss-up which motherboard was used for testing the X2 6400+. If you currently run a Socket 939 Athlon 64 and fancy an upgrade to AM2 then you'll need to buy a new motherboard and CPU as well as DDR2 memory in which case you'd be barking mad if you didn't switch to Intel's Core 2 Duo.
The only likely candidates for an X2 6400+ are already running a slower Socket AM2 processor in which case we doubt they're much interested in games. Yes, the nForce 570 and 590 chipsets provided a competent platform in mid-2006 but the only chipset worth considering for an Athlon 64 in 2007 is the AMD690 so we grabbed an Asus M2A-VM motherboard from the shelf and got on with the job.