Before I get an OCZ Reaper 1066Mhz (DDR2-8500) 4GB memory module , I had a 2GB Kingston 667Mhz value series RAM kit. Now I want to run a benchmark test with '4GB 1066Mhz' vs '6GB 1066Mhz + 667Mhz' using both my RAMs. Is this possible? OCZ reaper operates at 2.1v and Kingston operates at 1.8v . So using both RAMs at one time may occur a problem?