Issues with 2 pairs of TWIN2X2048-8500C5D

I'm using 4 sticks of these (2 kits) in a GA-P35-DS3L; I was previously using the same 4 sticks in a GA-P35-DQ6 and experiencing similar problems. Here are the problems:

- Vista background services and processes crash randomly.

- Graphic intensive games sometimes error.

- Computer very occasionally blue screens.

- Large files (1gb+) downloaded via bittorent etc often are corrupted

- Games that install from CDs take dozens of tries to install without an error

The 4th and 5th did not occur back on the P35-DQ6, but the first 3 did. I've tried many things, including asking on these very forums once before. These are the solutions i've tried:

- I've tested each stick individually; none of them produce errors in memtest separately.

- I've tested pairs in different bays, still produces problems.

- I've tried using only 2 sticks at both 1066 and 800, as these sticks are optimized with only 2 bays being occupied in mind.

- I've tried all 4 sticks at 800 rather than 1066.

- I've tried adding slightly more voltage, but I don't really know what i'm doing in this department. I have not tried any CPU overclocking, since I lack the knowledge needed. I've also done minor timing adjustments, to no avail.

I've shrugged this off for about a year now, but it has gotten much worse since the MB switch. Any attempt at a solution that involves running with only 2 sticks reduces the blue screens and crashing greatly, but does not address the corruption and installation issues, nor does it completely fix the crashing. The problems with large files is unacceptable. What else should I try to fix this problem?

I have already answered you on another post, please do not double post.

If you read this post more carefully, you'll notice that I tried that solution and it does not help stability at all. Could you please elaborate more, or offer a different solution?

Also, there have been hardware changes since the original post.