Where'd my memory go?

Last week I upgraded my memory from a 6gb kit to a 12gb kit (12gb Corsair DDR3 1600 1.5v 9-9-9-24) on my EVGA x58 motherboard. after some initial hiccups with not posting, i reset the cmos, manually set the voltage, installed and booted one stick at a time and things have been fine.

Today I see that 4gb has disappeared. Windows 7 x64 can see12gb installed, but oinly 7.99gb is usable. Anyone have an idea of what's going here?

the last thing you said you did was *UPGRADE* you ram . take it out its prolly gone bad is all. find teh *EXACT* ram NEW and try aaginz happy Gaming

Looks like you might be having the same problems as I did when I upgrade from 6GB of RAM to 18GB of RAM. I only had 16.5GB available after I upgraded.

In the BIOS change MCH Strap from auto to DRAM Ratio. It's located under Frequency/Voltage Control.

Also, in MSCONFIG, check to see if Maximum Memory is Enabled. If it is, DISABLE it. 'Boot' tab, Advanced Options in MsConfig.

Also, you can try changing the tRL from +0 to +2. Located under the Memory Feature in the BIOS under Frequency/Voltage Control

SlayVus: Maximum Memory was disabled. I could not find a tRL setting, but I changed the MCH strap to DRAM ratio . After I rebooted Windows now sees 12gb. I think that this particular EVGA board has problems correctly identifying this particular memory kit. When I installed it I had to manually set the timing and speed, as it was defaulting to 1066 mhz.

What was strange is that 12gb was always recognized in BIOS, but not by Windows.
Hopefully this solves the issue. Thx for your [H]elp.

the tRL settings can only be found in newer versions of the BIOS. I found it only in the newer 2011 versions of the BIOS (can't remember the exact one) so just upgrade to the latest BIOS (8/2/2011) and you can find the TRL settings at the bottom of the memory settings, under the extensive list of timing configurations. Also, for what it's worth, my tri-sli EVGA SLI LE board had the same issues. Just make sure you have the right amount of voltage running through the DIMMS. Usually they state the supported voltages on the box and website. Even newegg states the voltages (although I wouldn't put 100% trust in those numbers). My G.SKill 6GB 1333 kit supports 1.5 to 1.65V for example. Since I'm overclocking, I set the voltage to 1.65. The TRL is a new feature made to allow for easier/faster memory discovery for overclocked DIMMS. It is sometimes necessary to set the value to +2 so all the DIMMs are initialized/detected before the handoff to windows, after that, if the DIMMS are installed but not detected, Windows usually maps the difference in memory as "hardware reserved" and states your installed memory, and then the available memory is what windows had initialized at time of handoff.

when I said 8/2/2011, i meant to say 9/2/2011. sorry for any confusion

so far so good. if i have the same problem i will download the newer BIOS.