If the min system requirements are as high as you guys are speculating, how the heck are they going to get this to run on the Xbox which only has a 700mhz P3 IIRC, less RAM, older ver. Nvidea chip? Are they going to have to totally strip it down to bare essentials to get it to run?
Keep in mind that the graphics chip in the X-Box is almost directly coupled to the processor and memory bus, whereas a PC graphics card has to go through the slow AGP bus. They can make it graphically as good as the PC version with a much smaller memory footprint for graphics becuase of this( as both the CPU and Graphics chip can manipulate the graphic data). Add to the fact the X-Box is basically only runnning Doom 3, instead the bloted Windows OS and drivers, that lets the game fit in only 64MB of RAM.

it runs like 40-50 fps without enemies and 2-3 fps with one enemy (i think this is a alpha version issue, but at least you can shoot at the enemies, i remember i had an unreal 2 alpha 2 years ago or so and if u shot at the enemy the game crashed )

i've got a athlon xp 1,9 , 512 MB RAM and GeForce4 Ti4200, thats pretty good system but i couldn't play the alpha smooth with enemies on the screen, no problem without enemies though, it looks GREAT, a little bit to dark though imho
Move to DDR ram if you can, it'll run alot better. With a 1.3Ghz XP, 256MB DDR, Geforce 2 MX 400 I get around 12 FPS on most enemies (except the second part of e3_2).