Need advice on PC hardware

[TheManuel]

Hello.

I'm in the final stages of building my arcade machine and a friend has offered to pony up some money to upgrade the PC in my arcade cabinet and I need a little advice.

Based on the available budget, I zeroed in on these two alternatives:
Sempron 3400+ Combo
Athlon64 3200+ Combo

Either of those will cost me about the same when you factor in shipping cost, rebate, memory and the fact that I already have an AGP video card (ATI 9550).
My chinning bar is to be able to run all the MAME games that I like (non of them 3D) and all NullDC (Dreamcast emulator) supported games at full speed.

On the one hand, the Sempron 3400+ looks extremely attractive because it supports the video card I already have, is AM2 socket so memory is DDR2 which is cheaper than DDR and it does not have a rebate. 
However, although the Sempron is rated at 3400+ the actual clock speed is 1.8GHz whereas the Athlon 3200+ in the other combo is 2.2GHz and has twice the L2 cache at 512Mb.

My gut feel is that, despite AMD's rating system, the higher clock speed in the Athlon will make it more capable for emulation applications, even disregarding the higher L2 cache.

Any opinions?

Thanks.

[Hemi]

It's a pretty obvious choice, go with the Athlon 64 over the weak Sempron.

[kelemvor]

Sempron is crap.  It's their equivalent of the Celeron from Intel.  It's for people who can't afford a real processor.