Windows 7: Upgrading RAM ~ says RAM is 400Mhz when it's 1066Mhz

Hey, just wondering why my RAM is showing that it has a max of 400MHz when I've got 2 x 2gb of 1066Mhz RAM

System specs below.

Should be 533 MHz for dual channel 1066 RAM. Just to be clear, the RAM does not really run at 1066 MHz, it really runs at 533 MHz but its doubled because of the Double Date Rate (DDR).

Also the memory supported by the motherboard: "Supports PC 4200 (533 MHz) and PC2 5300 (667 MHz) DDR2 DIMM", with a max of 4 GB. If the specs are correct, your RAM exceeds the support of the motherboard.

http://h10025.www1.hp.com/ewfrf/wc/d...name=c00714578

Oh
Didn't know that! Would of saved me buying 4gb of RAM!

Would it better better if I use my 8GB of memory (CPU-Z showing PC2 6400) OR 4gb of memory of the PC2 8500 even though it's showing up as 6400?

If you NEVER use more than 4 gigs, then use 4 gigs of 8500--assuming it is in fact running at that speed and your motherboard supports it.

If you SOMETIMES use more than 4 gigs, then use all 8 regardless of their rated speed. You would have to monitor your usage to determine if that was true.

More is better, assuming you use it at least occasionally.

As far as I know, if you are running RAM of two different speed ratings, Windows will default to the lower speed and all sticks will run at that lower speed.

No, Windows has nothing to do with it. It would be your motherboard and the chipset used.

Yes, the mobo will default the RAM to the slowest RAM in the system. However, it seems that the OP has RAM which is faster than his mobo or CPU can utilize...so unless he goes for a crazy overclock....it's unlikely that he will ever come close to getting full speed out of the 1066RAM. That would require running a 533Mhz Front Side bus.

Yeah that's what I was thinking, I mainly play Battlefield 2 on the PC which is is really memory intensive I've heard.