Don't fall for it: I just put
these into my new PC. Running smoothly, but at DDR2-800 rates, not 1066 as advertised. Now the general verdict is that you need to set the rates manually (DDR2-1066 as well as 2.2V). Didn't do the trick, they are still displayed as 800's.
Just a little warning to anyone else looking to bump his system.