It's difficult to easily compare PC and console hardware specs since the platforms are reasonably different.
From another recent interview:
"Also, the 360 work we did resulted in an engine that also runs well on low-end and mid-range PCs. This is very important for games today; the high-end PC gaming market alone is not big enough to support next-generation games with budgets in the $10-20M range. You need to run on ordinary mass-market PCs as well. In reading PC gaming websites, one might get the impression that everyone owns a dual-core PC with a pair of $600 GPUs in SLI configuration, but the reality is very different. More than 80% of PCs sold today are still single-core, and have very low-end DirectX9 graphics capabilities. Unreal Engine 3 supports those configurations well."
http://www.pcgameshardware.de/?article_id=602522 is the whole article. I was surprised to hear UT3 is supporting SM2.0 cards :o since no other U3 engine game has so far. I guess I'll get to try out the demo on this radeon 9800 pro after all...