Speed or Quantity?

[sonic]

I am running Vista home prem. I currently have 2 gigs of 667 ram ddr2
I have 1 gig of 566 in two 512 sticks.
What is better to continue to run 2 gigs at the faster speed or install the other and have 3 gigs. but lose speed?

[raptorx]

It's not just the speed, but the RAM timings (latencies).  If all the sticks are not matched then the system will run at the slower timings.  You're best running just 2Gb unless all the sticks are matched.   Even then you'd be populating 4 DIMM slots and that's extra overhead and stress on the motherboard.

You can get 2Gb sticks and have 4Gb in just 2 DIMM slots and that's supposed to be easier for the memory subsystem to handle.

-Jim