Mixing memory capacities?

I have wintec ram right now can i get a 2gb x 2gb kit and use my old 1g x 1gb in ddr2 and still ahve increased performance?

Zilliak,
I personally always purchase as much RAM at the same time the computer is purchased that I think I would ever need, for example 4GB for a 32-bit computer and at least 8GB for a 64-bit computer.
That way they should be identical. Using a mixed RAM set normally doesn't work as there are so many variables, ECC, CL2, CL2.5 or CL3 PC3200 etc. And all RAM is not created equal.
lately i bought a high end workstation from a large manufacturer an it came with my extra RAM which was technically the same as they both had the same Item number. However, instead of 12GB of RAM I only ended up with 10GB, definitely a real bummer.

Generally, do not mix ram types. Always try to have the same type and speed of ram.

It will be the same just different Gb of memory so same timings and speed just 2 1gbs and 2 2gbs

That's perfectly fine to mix the sizes.

I think that's called dual channel asymmetric, you will be able to use all 6GB of RAM (it says you have 64 bit), but they will run at half speed.
Technically, it should work, but sometimes RAM doesn't behave itself.

This may help to explain the different setups:
http://www.intel.com/support/motherboards/desktop/sb/cs-011965.htm