I have an ASUS M3N78 PRO mobo running an AMD Phenom 8650 CPU in the AM+ socket.

I have installed 4x4GB Patriot Viper DDR2 1066 sticks, one in each of the 4 slots.

On boot, both in BIOS (1402) and in Win 2008 Server (64-bit), only 8GB RAM is recognized.

According to User Guide from ASUS, pg xi,:
"DDR2 1066 is supported by AM2+ CPUs only. Refer to or this user manual for the Memory QVL).

What is particularly perplexing about this subject is that this good PATRIOT VIPER Series RAM is not actually listed on Memory QVL, however, neither is any 1066 RAM listed there higher than a 2GB DIMM.

I have tried manually setting to 1066 in BIOS, however this causes BSOD.
When DRAM Timing is set to AUTO, boot shows 800 ganged.

I also tried changing from AUTO to lower speeds, such as 800 and lower, however, it still only recognizes 8GB.

Any ideas would be greatly appreciated. Thanks,
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  1. According to asus specs, your board only supports up to 8 gb total of ddr2 (2 gb per slot). Populating all 4 slots may cause the ram speed to decrease on some boards. It's a limitation of the board chipset or bios. You may try changing the ram voltage to run at 1066, but your limit will stay at 8 gb.
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