There a a lot of problems with this 1066 Mhz memory and this motherboard, there is specific 1066 Mhz memory that you can use, please look at the gigabyte website. U use 800 Mhz without any problems.
2ndly, when i started my computer and installed vista it told my that i have only 1 GB (i bought 2x 1GB), i needed to switch the bench.
3rd, only use the drivers provided on the gigabyte website (don't use ati catalyst for example), but if you have problems then try. This should prevent you a lot of issues.
I can't tell you how much 1066 is quicker.
Also check this:
http://forum.team-mediaportal.com/ht...0g-780g-40706/