ATI Radeon X1800 vs. XFX Radeon 4850: equivalent??

Hello,

I want to run Star Trek Online. The graphics card they require is at least an ATI Radeon X1800. I have a XFX Radeon 4850
card. Is the 4850 at least as powerful as the X1800?

I did try to figure this out on my own at wikipedia, but I'm afraid it's way over my head. I also see ebay sales for the
4850 for around $50 and the X1800 for $10 cheaper. This suggests the 4850 is a better board, but I would appreciate a
technically savvy person telling me, so I can be sure.

Many thanks.