Opteron Vs. Athlon X2

[Robert L Cochran]

I'm Christmas shopping and in need of advice.

I'm currently using a machine that has an Athlon 64 3500+ (single core) 
processor with an MSI K8N Neo2 Platinum motherboard. I'm using 2 Gb of 
Adata memory which is actually running on 2T timings. The motherboard 
was flashed with the v1.9 BIOS which upgrades the board to processor E6 
CPU (I'm not familiar with the "E6" terminology.)

Now I'm on the Monarch Computer website looking at Athlon X2 and Opteron 
processors, and I'm wondering which one would be a really good step up 
for me for the next 2 years -- preferably without having to get a new 
motherboard.

Does an Opteron dual-core give me any advantage over the Athlon X2 
besides a bigger L2 cache?

Can I run Fedora Core 4 (and later on, Fedora Core 5) on the processor?

Can I take an Opteron processor and drop it into my existing MSI 
motherboard, or should I expect to buy a new motherboard also? If so, 
what motherboard?

What would be better for a developer -- the Athlon X2 or the Opteron?

Thanks

Bob Cochran
Greenbelt, Maryland