Doom 3 lag issues

[HeXploiT]

I'm getting some slowdown issues in doom3 but i can tell it's the drives and not the videocard that are lagging. I'm running in ultra mode so the standard "set image_useCache" isn't applicable. When i run the command "timedemo demo1 cache" on the same setting though it flies through it without any hiccups or studder and averages 37fps@1600x1200x2AA(ultra detail). If i can run the demo so smoothly with the cache command then there must be a way to smooth the gameplay out.

System is dual seagate 80's @5400rpm -raid 0 array, ram is 1gb kingston valueram, 3200+ clawhammer, Leadtek 6800 GT 256mb.

Anyone have any ideas?

[kc32]

*gets out 1600-page computer hardware guide*
*turns to page 580: RAID arrays*

Ok, now that I know RAID 0 is the performance option, I can only guess that
A: Those 5400 rpm drives are too slow
B: You need to defrag, or
C: Something's not set right, possibly in BIOS.

[Ultraviolet]

Hell, even in something as old as Enter The Matrix they suggest that you get 7200 RPM drives in the system requirements. If you want performance drives, go all out and buy solid-state or get yourself a couple of full-featured 10,000 RPM drives.

[kc32]

The hard drive is one of the places I cut corners when I built my computer. Still runs damn fast though.