AMD 3500+ or Opteron 165

[One4yu2c]

That's one of the advantages of the Opteron processors, is they all ship with the full 1MB L2 cache. However, I'd caution against putting too much weight on the performance difference between 512KB vs 1MB. A very good read/comparison with lots of benches can be found on here:

GamePC : Dual Core Done Right

The biggest difference can be found in some gaming, and even then, clock for clock, it's only noticeable in benchmarking. And for nearly everything else, it's virtually a wash. It's nice to have it when possible, but I wouldn't recommend paying extra for the cache, as the return on investment just isn't there.

EDIT
For reference:
4200+ X2 = 2.2GHz, 512KB
4400+ X2 = 2.2GHz, 1MB
4600+ X2 = 2.4GHz, 512KB
4800+ X2 = 2.4GHz, 1MB
FX-60 = 2.6GHz, 1MB (unlocked mulitplier)

Opteron 165 = 1.8GHz, 1MB
Opteron 170 = 2.0GHz, 1MB
Opteron 175 = 2.2GHz, 1MB
Opteron 180 = 2.4GHz, 1MB
Opteron 185 = 2.6GHz, 1MB

[Capper]

If you have no plans to OC, skip the Opty. The general consensus was that since the Opteron is a server processor, its tested harder and held to a higher standard than the desktop line. Early Opterons showed to be excellent OCers, but later revisions weren't nearly as good (I had a very early 165 that ran 300x9 all day every day without breaking a sweat.
All things considered, you will see a slight performance hit going from 2.2GHz to 2.0GHz, but the trade offs now, and in the near future make the 3800+ X2 worth it....IMO

[wtcnbrwndo4u]

Definitely jump for a X2 4400+. The price has dropped incredibly and is a great deal!

[GV2NIX]

One4yu2c pretty much summed up everything I was thinking. So well in fact, that I have little else to say!

I don't have any AM2 experience, but I'll take their word for it that it's almost the same at this time. I have been extremely happy with my 170. It overclocks very well, and it functions seamlessly with my mobo and RAM. If you do end up overclocking it though, it must be cooled properly or you're not going to the results you're looking for. I have mine paired with an XP-90C with a 92mm Delta fan and I think that is sufficient for the speed and voltage I'm using.

I'd be happy to answer any more questions you have.

[onebxr]

Thanks guys for all the replys. I think I am gonna keep the 3500+ for a few months, maybe try my hand at overclocking a bit with it. This way if I fry the 3500 I can have a legit excuse, to give the wife, to buy a new one:) I guess now its time to learn what all those numbers and letters mean in the bios. Woot I'm scared HAHAHA
I know to take it slow, and believe me I am gonna be very conservative.
-1

[gvblake22]

Originally Posted by onebxr

Thanks guys for all the replys. I think I am gonna keep the 3500+ for a few months, maybe try my hand at overclocking a bit with it. This way if I fry the 3500 I can have a legit excuse, to give the wife, to buy a new one:) I guess now its time to learn what all those numbers and letters mean in the bios. Woot I'm scared HAHAHA
I know to take it slow, and believe me I am gonna be very conservative.
-1

Check our AMD overclocking Guide

[polobunny]

Originally Posted by Capper

If you have no plans to OC, skip the Opty. The general consensus was that since the Opteron is a server processor, its tested harder and held to a higher standard than the desktop line. Early Opterons showed to be excellent OCers, but later revisions weren't nearly as good (I had a very early 165 that ran 300x9 all day every day without breaking a sweat.
All things considered, you will see a slight performance hit going from 2.2GHz to 2.0GHz, but the trade offs now, and in the near future make the 3800+ X2 worth it....IMO

I was about to point that out. (Optys)
Personally, i'd check what your 3500+ can handle if you're planning to overclock. In my case, I upgraded from a 3700+ that could run 2.7ghz all day long without a problem to a 3800+ X2 that barely does 2.5ghz with reasonable voltage. Anything over this will make it fail stability tests, no matter the voltage. (yeah, seriously)
It was a bit of a lost on some points, and a gain on others. All in all I feel like I ended wasting money because my 3700+ really ran fine and could hold with this 3800+ X2 in terms of overall performance.
However, I can't say i'm not pleased by it. I sure would have hoped more, but it isn't digusting performance either.

To tell you the truth, in the last weeks i've been experiencing with a few machines. Core 2 Duo, Athlon X2 socket AM2, Athlon X2 socket 939, Pentium D's and various memory kits ranging from "high performance memory" (Corsair, OC-Z, Kingston Hyper X) and some "low performance memory" (Samsung OEM, Kingston Value RAM)
Before starting the experiences I wanted to get a Core 2 Duo pronto seeing those SuperPI times. But after testing more and more, I saw that the real world performance was not quite worth the price of an upgrade. Furthermore, a socket 939 Athlon X2 was just as fast to load Windows than a Core 2 Duo, give or a take a few seconds. Testing some high performance memory kits of DDR2-800 on Athlon X2 AM2 proved little to no difference compared to my DDR-500 memory. Not only in real world performance but also in benchmarks, believe it or not. If difference there was, it surely didn't motivate me enough to upgrade... I even found that alot of benchmarks on certain websites were exagerated, or the guys that ran them were on illegal substances.

Anyway i'm going out on a tangeant, but what I want to say is: Do you really need it? What exactly is not satisfying enough about your 3500+?
Alot of times i'll find myself buying a new piece of hardware stictly because I want better, not because it is needed.