Problems after upgrading RAM

So I have been using Windows 7 RC1 for a while with no problems.

EDIT: (Wrong board before) Gigabyte GA-P35C-DS3R rev1 board
q6600 core processor
4GB G.Skill F2-6400CL5D-4GBPQ RAM

My problems started when I tried upgrading to 8GB of RAM. I bought exactly the same RAM as before to avoid any compatability issues.

However when inserting my computer wouldn't boot, just giving a black-screen. Typical sign of faulty or poorly mounted RAM. I pulled it out, and also swapped it around (ie the stick I had in the right RAM bank I put in the left, and vice versa), this time the computer started fine. BIOS read all the RAM etc.

However Windows 7 took like 5mins to boot. The operating system was completely unresponsive, and CPU usage was at 100%, on all 4 cores, hmmm.

I decided it might be faulty RAM, however the Windows performance monitor rated the RAM as a max 7, higher than before, which would seem odd if the RAM was dud   . I decided to it may be a compatability problem, and attempted to do a clean OS install.

Insane install process, sitting doing nothing for extended periods of time, and eventually taking 4hours+ to install, the completing installation step alone took over an hour. Afterwards win7 was even worse then before.


Step 2. Wiped everything and reinstalled Vista, quicker but seemingly slower then what I remembered. Installation finished, and OS was responsive, though still seeming to have high CPU usage, (pull the RAM CPU at like 1-40% usage - with the 8GB in 30-90% usage). Also boot times are noticably slower, and when installing updates it can take 5+ mins longer to respond.


Anybody got any idea what is happening here? Compatibility problem? Faulty RAM? Any tests I can run or something?