The 3800 definitely, It's the X2 processor that has the best value for money. There are two series of X2 processors, one with 512 kB of 2nd level cache and one with 1MB of level2 cache. The first series is also known as 'Manchester' and the second as 'Toledo' As of now the Manchester 3800 is the X2 processor to buy, it just has the best price/performance ratio of all X2 processors. All X2 processors are basically the same, they only differ in Level2 cache (512 kB or 1MB), and in clock speed. The 3800 has two 2.0 GHz cores and 512 kB of level2 cache per core. X2 processors at 2.2 and 2.4 GHz, with 512 or 1MB cache are also available, but they are disproportionally more expensive at the moment.
To be honest, I may spark controversy here, but the 4200 looks quite viable in the UK at least, its not much more than the 3800 and performs admirably better...
It performs 10% better, because it runs at 2.2GHZ vs. 2.0GHz or 10% faster. I just built my signature rig three weeks ago, and got a 20% overclock (equal to a 4600+) with stock heatsink, fan and 1t timings, load temperature was 43-44C. This weekend finally put in the new ThermalRight XP-90 that I received right after I had finished my build and load temps are down by 10 to 11C (more than I would have thought), so now I'm going to try for a 30% OC after I let the Artic Silver 5 get at least most of its 200 hour burn in time out of the way. The difference in cache size has little effect on performance per several tests available on the net, it all comes down to processor speed. So buy a 3800+ X2 for $315 or a 4800+ X2 for $780 or whatever in between, but the "value" is the least expensive chip, especially if your comfortable with OC'ing. http://www.techbargains.com/ Chip prices from above link.
I'm not sure that I am, I'd much prefer a system that hasn't been touched, and therefore I think the standard would be good enough.
