RAM Speed

I just bought a stick of PNY 512 mb pc2700 ram and want to add it to the ram in my desktop comp but that ram is 128 pc2100 so my max speed would be the pc2100 ,and i was wondering which would be better running it at 640 mb pc2100 speed or 512 mb pc2700 , im guessing 512 mb pc2700 , but was wondering what yall think

 

I's say you would be better off with 640mb on 2100, only because your mobo was running previously on 128mb 2100. I assume your mobo isn't really up to date if it still supports 2100 so i would say your whole config is based on 2100 so that is not the only bottleneck in your pc.
On the other hand i would not advise using a pc2700 capable bank to run on pc2100... hey you are right! i don't even know how i would set it up myself

 

You can probably use your new stick of pc2700 with your existing 2100 but it will only run at 2100 speeds.
If you wanted to try to run at 2700/333fsb you will have to remove the pc2100 stick, and probably have to manually set the mem timings in bios.

It's best to run memory fsb equal to the fsb of your cpu.
I doubt youll see any performance gain trying to run memory faster than the cpu fsb.

Sometimes two different brands or even two different speeds of mem will have conflict running togather, try it a see.

Best bet is to run both sticks at 2100, if they are compatitable.

 

If your CPU is set to run at 2100, you should run your system at 2100 speed. The CPU is what sets the system "clock pulses", which IS your systems FSB. Making it work at 2700 Would be OCing the system, and I'm not sure if you want that (but I don't know, maybe you like to OC). Your memory speed can be higher than your CPU FSB, in fact, some people do this so that when they buy a faster CPU with a higher FSB, they don't have to buy new RAM. There really shouldn't be any conflictions with the mixed RAM, but I woyuld run it at 2100.

 

my cpu is currently running at 2100 but i know my mobo is capable of running at 2700 , under its properties it says i can , I guess i'll have to try them both see which i like.