I suspect that you really do not have DDR2-1066 RAM. I suspect that what you do have is DDR2-800 RAM being pushed to the higher frequency by increasing vRAM and relaxing the timing. The 2.2 - 2.3 volt recommendation is a clue to this.
Decrease your memory clock so that CPU-z indicates an FSB:RAM ratio of 2:1 (205X2) and see if blend fails.
Another thing you can try is to relax the timing to 6-6-6-18 and run at 410X2.