I do think I recall you're using 4Gigs of ram correct? If that's so then you are using 2Gig sticks for your ram which I do believe to be slower than actually using four 1Gig sticks of ram (it does make a difference). Also since XP and Vista 32-Bit both don't support more than 3.x Gigs of ram then you have too much in your system.
Also I've been hearing lately that it is actually BAD to install more than 2Gigs in a system that is running SLI/Crossfire. I'm not sure exactly the reasons yet as it may be something as simple as driver issues with more than 2Gigs. If you have the extra ram lying around (or some extra loot) it might not be a bad idea to get a matched set of 1Gig sticks to try out.
3dmark doesn't really tell you the whole story about your PC. This is ESPECIALLY with ram...if you were to run a 3dmark test with 1Gig of 1066 ram in your system you'd score better than if you had 2Gigs of 800 ram because 1066 is way faster than 800 speed. Obviously in the real world we live in that 2Gig system would beat that 1Gig to kingdom come because games don't load entirely into ram (unless you're playing a really really really really old game that's like 0Gigs) but 3dmark does.
Don't take the results you get from those programs very seriously as they mean nothing in the real world.
Did you verify that your ram speed in CPUZ is actually stated as 400Mhz (which is 800Mhz since you're using DDR2 aka whatever number you get is double)? Yes those timings would help you but probably not to a level you'd actually notice in actual use but they'd look cool. You can set them if you'd like as long as you know the voltage they're suppose to be run at.
Go to your manufacturer site and find out the optimal voltage (very important) for the listed timings before you set the timings. You don't wanna set it too low as it may run but you'll get random crashes, or it may not run at all. You also DEFINATELY don't want to set it too high as you'll just burn it up well before it's lifespan is over.
I imagine the voltage is around 2.1 or so maybe less, maybe more. If it's anything ridiculous like 2.3-2.5 then I wouldn't bother with that unless you have some heatsinks ON the ram and/or a fan that blows directly on them as that'd get too hot for daily use. You'd be better then setting the speed a little lower and letting that be that.
You can also modify your ram speed by the Bus/FSB frequency but that's also overclocking your processor and best left alone until you've done enough research to understand that. That or of course you have enough money to buy new components lying around. It's not the most dangerous thing in the world but I never recommend someone who's not familiar with it to just try it as it can bring heartache and takes lots of patience ESPECIALLY with the Phenom which is very old school.
I like that the processor isn't one of the oh so common processors that everyone overclocks as though it's some god given right that MUST be put on every single processor. I remember the days where you were $hit happy just to get a couple hundred Mhz (as in 200) over stock speed. Nowadays it seems like if your processor can't overclock an extra 2Ghz then it must be trash? That's like saying the new car you bought is junk cuz you can't easily get 400hp from it...if they wanted it to run like that they would've done that in the first place. Overclocking/uprating is a gift...not a requirement.
That said the Phenom does overclock well as long as you actually know what you're doing and you put in the effort to get what the chip has and not what you think it should have.
/rant
K