homepage Forums Technology Hardware & Software - PC Memory compatibility question

This might be a bit speculative, but no harm in asking.

I bought 16GB of RAM (2x8GB) to upgrade the 8GB I had. They work absolutely fine, but I was optimistically hoping to also use the previous 2x4GB sticks for a total of 24GB.

Unfortunately the system wouldn't even post with both pairs installed. Tried it with the 8GB sticks in slots 0/2 and the 4GB in 1/3, and vice-versa, but no joy either way.

I'm just wondering whether this should be possible? I know sticks of dual channel RAM are supposed to be paired, but no idea whether you can mix pairs of different specs. Same manufacturer, just different timings.

Relevant specifics are:

ASUS P8P67 Deluxe motherboard
2x8GB Corsair XMS3 C11
2x4GB Corsair XMS3 C9

Any suggestions much appreciated.

What version of windows do you have ,,, Home, Premium or Ultimate??

Home Version is limited to 16gb ..

Good point, I'm on Home Premium at the moment.

That shouldn't have any effect on it booting tho'. Even if it did, I'd imagine Windows would run fine but just be limited to 16GB.

Voltage differences between the modules?

If the available options in the SPD/XMP didn't overlap, I guess it would still have posted.

Some chipsets and motherboards can be picky, with some improvements with later firmware. Did you check if FW updates mentioned any improvements in memory compatibility?

they appear to be the same voltage..

Brun are they being recognized in BIOS??