Dee said:
AMD Athlon 64 and AMD Athlon 64 FX are 2 different animals. They are related,
but they are different - like two brothers. Decide which one you're talking
about!
So... Why are they so different?
What's the big difference between a Socket 939 A64 and an A64 FX, other than
[possibly] the clock speed and the cache?
The difference is cache size and clock speed. The FXs have 1M of cache,
the regular Athlon64s have 1/2M with the single exception of the 4000+
which is identical to the FX-53. The fastest A64 is the FX-55 which is
2.6GHz and 1M of cache. The 4000+ is 2.4GHz with a 1M cache. The 3800+ is
2.4GHz with a 1/2M cache.
Some of the 754 pin parts also have 1M of cache, the 3400+ is available
with 1M (there is also a version with 1/2M) and the 3700+ is 1M.
It turns out that cache size is very important. I have a 3400+ and a 3800+
system. On compute bound verilog simulations (i.e. no disk I/O just
computing) the 3400+ is twice as fast as the 3800+ even though it has a
slower clock and more then twice as much main memory bandwidth. So for
desktop applications I'd recommend a 3400+ with 1M (not the 1/2M version)
or a 3700+. The 3400+ is $209 on Newegg, the 3500+ is $275 and it's much
slower than a 3400+. The 4000+ is $599 and the FX55 is $900. Spending $900
for a processor makes no sense. If you have the budget for that the much
better choice is a dual Opteron system. The Opteron 246 is only $311 so
even with the more expensive motherboard a dual 246 system will cost about
the same as a single FX55.
