more memory, less video?

I bought a stick of 256mb pc2100 ddr from a second hand computer shop today, when i got it home I realised the guy had made a mistake and gave me pc2700 instead. Both have different timings 2.5-3-3-6 for pc2100 and 2.5-3-3-7 for the pc2700, so what should I set the timings at? Baring in mind I'm overclocking.
I've been using pcpitstop to benchmark my crappy on board graphics, when i test the sticks seperately I get 245 MP/s, but together only 205 MP/s, where did the other 40 million pixels go?
Any help would be appreciated.

 

Are you using the PC2100 and the PC2700 DDR SDRAM sticks together on the same mobo? You should only run the same type (PC2xxx) RAM, never mix them up....

 

Yeah, I don't like the idea of mixing memory types but isn't pc2700 supposed to be backward compatible? Is that what's causing the graphics reduction?
Anyway I was the guy who bought the Gigabyte mobo which turned out to be an oem version from a Packard Bell, don't know if you remember the whole saga or not? Anyway i managed to cross flash the really basic AMI bios with the Award one from the Gigabyte website, guess I got lucky.

 

Under the best cases the pc2700 will run as pc2100 but its not the best idea; running diff mfg of ram ussally brings trouble and decreased performance. But you can always give it a try.