HP DX5150 vs. Dell Optiplex GX620

I'm looking for a cheap control computer to run LinuxCNC on. For the time being, I'll be using software stepgen but I'll probably switch to using a Mesa 5I25 at some point. I've found two very cheap small form factor PCs and was going to grab one of them, but I was wondering if anyone had a good reason to pick one or the other:

HP DX5150
AMD Athlon X2 3800+ 2.0 GHz Dual Core 64 bit CPU
ATI Radeon graphics with VGA out
1 GB DDR Ram

Dell Optiplex GX620
Intel Pentium Dual Core 3.00 GHz Dual Core 64 bit CPU
Intel graphics with VGA out
2 GB DDR2 Ram

I figure RAM doesn't matter an insane amount, though dedicating a GB of RAM to a ramdisk and running from that might not be a horrible idea. I'm curious what people think of Intel vs. AMD. I couldn't see an extremely clear case for either on the performance pages, but AMD seemed to have lower numbers overall (but a smaller sample set, and correlation != causation). Then there's the discrete vs. integrated graphics. I'm imagining discrete being better due to reduced memory contention? And then last but not least there's pure instruction retirement rate which the Intel probably wins at.

Any thoughts? Should I just pick one and run with it?