AMD doesn't include the same 3d instruction set as the Intel chips, but generally speaking, few or no software is written so specifically to Intel products that it will not run at all on an AMD chip. Most software takes both manufacturer's sets into account and will run equally well on each. Occasionally, you will need patches, but those are usually pretty available from the software maker.
Chances are, your problem won't come from the CPU, but from the rest of your hardware, esp the motherboard. I've seen some isolated issues with most of the AMD boards, but I don't really think it's any worse than Intel in that respect...
As a side note, Dell is a great system to recommend to friends who aren't overly tech-literate...they're fairly stable systems and they've got great tech support (so you can tell your friends to call them instead of you in the middle of the night)...
~Ladi