I have OCZ DDR2 800mhz and the problem is that i have a DELL VOSTRO 200, i cannot seem to find a way to change the voltage to 2.1V can anyone help me please?
This may not be the answer you're looking for but I would imagine that Dell computer's rarely offer one the ability to adjust their VDIMM. Although I cannot be certain without knowing the make and model of your motherboard...
Even if you don't have the ability to raise the VDIMM, you could always mod the BIOS, mod the board, or buy a booster.
TBH mate, there is no real benefit for you to get faster ram, one of the main reasons being, as you found out, you dont have enough options (fsb:ram divider) in the motherboards bios, so even if you get the fastest ram out there it will still run at (well depends what fsb your current cpu has got, then times it by two, if 266Mhz fsb then DDR2-533). well, if youre in need for MORE ram, then get any ddr2 ram along your cpu's fsbx2 (you can find that out, by downloading cpu-z) and youll be fine.