Dell :: Latitude D820 Upgrade Time

I have a Latitude D820 with T2500 Yonah, 1024mb ram (2 bank: 512mb), and Quadro NVS 120M "video card." I tried running NFS: Pro Street, and even on the lowest settings and resolution, it lags. I think its time for some upgrades... I have a couple of questions first.

Video Card/GPU: I know the 120m isn't a gaming card, however, the GPU IS a GeForce Go 7400, the same as the fx350m found in the Dell PRECISION M65. How is it that the precision, with the same exact same motherboard as the d820, can run a higher fps on 3d heavy apps? I know that the 120m is "optimized" for 2d drafting, but it doesn't make sense why it would be slower if it is the same gpu on the same motherboard. (excluding drivers and software based overclock).

I guess my questions are,
1.) What's the PHYSICAL difference between the D820 motherboard with the quadro 120M and the M65 with the fx350M?
2.) Is there a gpu bios I can flash to make the gpu optimized for 3d gaming? I don't care what windows recognizes it as, as long as its optimized for 3d. Use m65 bios maybe? How much does bios affect performance in game/app?
3.) What is a safe overclock speed and peak running temp for the gpu in the D820? The defaults are:
Low: Core 200mhtz, mem 400mhtz
High: Core 450 mhtz, mem 700mtz.
and averages 70 deg C idle and peaks 95 deg C load

Ram:
4.) Can the motherboard utilize ddr2-800(pc2-6400) or is it "limited" to ddr2-667(pc2-5300).
5.) The default ram latency is cas 5, 5-5-5-13. Can the mo-bo utilize a cas 4, 4-4-4-12 @333mhtz (ddr2-667)?

I already updated to the newest driver for the video card.