2GB OCZ Platinum PC3200+ 2x 512MB Corsair 3200LLPRO PROBLEM

Hi, recently I got rid of 2x 512MB modules of RAM from my PC, and replaced them with 2x 1GB modules OCZ Platinum RAM. I now run 2x 1GB OCZ & 2x 512MB Corsair, at 2.3.2.5 timings. I have a problem however, before replacing my old 2x 512MB modules of RAM with the new ones, I had a Vista Score of 5.2 on the RAM. Then I popped in these 2x 1GB sticks, and my Score went from 5.2 to 5.0 with 3GB of RAM. Now my question is, shouldn't the score be higher with more RAM?
Also my memory bandwith fell from 6200MB/s to 5900MB/s.

I have discovered that when I remove the 2x 512MB modules Corsair, and set the memory Command Rate from 2T to 1T, the Vista Score goes to 5.9 for only 2GB of RAM. Since I cannot run 1T with 4 sticks of RAM, I am forced to use 2T. Anyone have an idea of how I can improve my performance.

P.S. The modules are running at around 406-407MHz in Dual Channel.

Leave the 2 modules of 1GB with the 1T Command Rate. It has the best performance/size ratio. You wouldn't notice much difference between 2 & 3GB anyways & mixing different ram brands & sizes is never recommended.

Ok, well after a bit of tweaking, I got all modules to run at 433MHz, and with timings 2.5-3-3-7, and I tweaked the Async latency and all the other settings to their best potential. I ran prime95 and memtest for 5 hours, and no errors. Then I re-ran Vista's Score tool, and it came up with a 5.7 on the RAM, which I think is way better than 5.0 or 5.2. I ran Sandra, just to check and my bandwith also improved. Then as a test I ran Crysis, and I noticed that it does not lag, stutter or freeze at all, and my frames have improved by 2-3 fps over 2GB of RAM. So after all I think I made a good decision in investing in more RAM. The tweaking and testing of the memory took me a very long time, about 6 hours, I kept playing with the bios settings until I got every component running to its top potential. Thanks for your help everyone.

if you have 3GB of RAM, you can't run dual channel. Therefore you lose (theoretically) half the bandwidth. With 512MB RAM (2x256), 1GB RAM (2x512), 2GB RAM (2x1024 or 4x512), or 4GB RAM (2x2048 or 4x1024) dual channel is possible. But with an odd number of GB of RAM, you lose bandwidth and therefore performance.

Yes you do run dual channel. The reason you do is because the RAM sticks are matched pairs of 2. I can even confirm this with Sandra and CPU-Z. They run in dual channel. The only difference is that the command rate is at 2T. If it would be single channel, I would not be getting a bandwith of 6839mb/s in Sandra

He has two 1GB dimms and two 512MB dimms. So a little math lesson is now in order 1GB+1GB+512MB+512MB = 3GB. He's running dual channel with 3GB of memory. He's also probably running at 2T memory timming which should reduce his memory bandwidth quite a bit.

*EDIT* NFSFAN responded while I was figuring out what to say. And how the heck are you getting 6.8GB/s bandwidth in Sandra with four dimms and T2 timing? I have the same board and an FX-60 clocked at 3.0GHz and slightly lower memory timmings and a command rate of 1T and my memory is clocked at 500MHz and I get 6.6GB/s-6.7GB/s? I've seen 8GB/s but I know that was an error on Sandra's part. /*EDIT*

Yes, Cinders is right. 2T reduces my bandwith, but its nothing to die about. I did a test with 2T and 1T with 2 sticks of RAM, and at 2T I get about 6800mb/s, and at 1T about 7500mb/s.

EDIT: In most of the games I have tested, I have noticed no performance drop whatsoever.