I have a P4P800 ASUS bd with P4 3.4Ghz and two sticks of 512mb Corsair DDR 433MHZ. I ordered two 1Gb Corsair DDR1 400mhz ValueSelect sticks since I could not find any Extreme Memory 433 in 1GB on the net. I reformatted and reinstalled XP and my screen was flickering so I thought maybe the two 1GB sticks were causing it. However, the flickering continued with the original memory. I did a second reinstall after I cleaned the XP disc. The flickering is gone, but I'm hesitant to try the 1GB 400 memory. Should the DDR1 400 work ok with the older DDR 433 since they are both Corsair?
Thanks Saint. The first time I added the two 1GB sticks of 400 to my two 433's, the screen was flickering and the computer was acting weird. I had just reformatted and reinstalled XP onto a second HD. The flickering problem was actually due to a slightly dirty XP installation disc. I think some of the installation files were not quite right. I cleaned it with distilled water and wiped it out from the center with microfibre. Now it's running great.