AnandTech has done a comprehensive
review [2] on CPU performance in DOOM3. The rest of the article covers the differences between many different models of processors. The big news, though, can be seen in the chart below.
I know from our recent poll that many of you are considering an upgrade for the newer games like Doom 3 and HL2. If so, you might want to read through this article on the different CPU's first. AnandTech has a recommendation in the mid-range price CPU's.
Making our way further down the chart we see that the Athlon 64 3000+ is quite possibly the best buy for excellent Doom 3 performance, weighing in right between the two Extreme Edition processors at less than 20% of the cost of those chips.
I wonder if the results will be similar for HL2. If AMD performs better on HL2 as well, they may have a real winning processor line on their hands -- at least as far as the gaming crowd is concerned.