Will this work? -- Dual Channel - 3072MB (512x2, 1024x2)

Currently have 4 sticks of DDR2 400 - PC3200
512MB Each resulting in 2GB

I want to swap 2 of the 512's with 2 sticks of 1024 resulting in 3072MB

It's Dual Channel, my MoBo supports up to 8GB

Will that work?
(before why, it's the only test I fail for yougamers.com recc specs for AoC)

EDIT:
Would using a 4GB flash drive w/ ReadyBoost be equivilant?