$30 for 2gb, can't decide which

I made a thread similar to this a while back, but that was just to find out the difference in speeds. Now that I know there is a marginal speed difference in 5300/6400 ddr2 RAM, I have a new question.

I'm planning on spending $30 on RAM, and newegg has 6400 2x1gb and 5300 2x1gb for both that price.

Right now, my specs are Sempron 3600+, Geforce 6150 onboard, 2x512mb 5300 ddr2 ram (4 memory slots), Vista (Dell Inspiron 530s).

What would give me the biggest performance boost for my $30?

3gb of 5300 or 2gb of 6400?

I mainly want it for performance in somewhat older games (Dawn of War, Command and Conquer 3, Occassional WoW Battlegrounds). Yes, I know the onboard is whats killing me I'm planning on getting a radeon 4650 but I want to know which RAM decision would best accompany the new card/current onboard until they arrive.

I concur with jedimasterben and recommend that you go with the 3GB even though it's mathematically slower than the 2gb option. I wouldn't worry too much about the speed whatsoever as you're running an AMD processor so the speed rating is almost insignificant, but seeing that you're running Vista, the extra RAM will almost be essential! Good luck!