That's why I post these questions at "Overclock.net" My 2006 Dell Dimension E520 is running 3.72GHz, and has gone 4GHz with a locked BIOS. There are other methods of overclocking. I just want to know what memory chips have the best chance of working with the timing available to me. This is my hobby, overclocking computers with locked BIOS. It's not simple, its not easy, but it's a lot of fun when it works, and I learn a few things along the way. I have 1066 RAM, it only runs at 800. It's not a problem. It's a challenge.