I recently upgraded my RAM with hopes of overclocking my i7-920 further. I had 1333 MHz RAM previously and couldn't move up my system bus speed any higher (RAM was at 1328 MHz) without instability. So I picked up a set of 3x2 GB Corsair 1600 MHz sticks.Installed them fine and Windows 7 (64 bit) booted fine. I checked the system info screen though to see it state "RAM: 6.00 GB (4.00 GB utilizable)". I shutdown, reseated the RAM and restarted getting all 6.00 GB showing up. Over the past 3-4 days now I've had Windows boot from a cold boot with the above 4.00 GB utlizable message. If I then shutdown and restart immediately (restarting doesn't work), all 6.00 GB shows up as usable.I've run internal memory tests in Windows 7 without issues with all 6 GB working (as long as Windows sees them). I haven't had a chance to get a CD-R at the store to make a boot disk for memtest86 or similar. I have definitely thought about a bad stick, but it seems odd for it to show up once in a while and then not at other times.Any thoughts or suggestions? I'd like to avoid the hassle of an RMA if this isn't related to bad hardware.System:Windows 7 Professional, 64-bitIntel i7-920 at 3.5GHz (Megahelam cooler)Gigabyte socket 1355 motherboard (think it was GA35-EX58-UD3R...I get these numbers mixed up a fair bit though and would need to verify)Corsair 3x2GB 1600 MHz RAM 9-9-9-24Corsair 750W power supplyGTX 285 1 GBSoundblaster Audigy3xSATA hard drives, 2xSATA optical drives

Hi,Did you clear the CMOS after the new ram went in? Sometimes it wont even post if not. Maybe go into the bios and write down all of your overclocking values, then reset the CMOS and set your O/C back up. :smile:David.

I had the same problem with my ASUS MB. Upping the QPI/DRAM voltage worked for me.The following link applies to all X58 Motherboards.Ram detection

I had the same problem with my ASUS MB. Upping the QPI/DRAM voltage worked for me.The following link applies to all X58 Motherboards.Ram detection

The link that SimNutt posted has great information and if none of that works it maybe a faulty set of ram.I had a 3*2GB set of Muskin ram that did the exact same thing you are describing. First cold boot in the morning only 4GB would show in BIOS, shut completely down (not restart) and boot again and all 6GB would show up. For the rest of the day anytime I shut down or restarted all 6GB would show up. The next morning after sitting all night the same thing, first boot only 4GB would show up.I was lucky enough to have access to another X58 PC and another set of 3*2GB Mushkin ram. The faulty set did the exact same thing in both PC's and the good set worked exactly like it should in both PC's. I RMA'ed the faulty set back to Mushkin and the replacement set they sent has worked fine every since it was received last September.So, if nothing in the link works you may just have a faulty set of ram.

Is the RAM you bought compatible with the board? On my p6deluxe 2 the Corsairs actually required me to somewhat randomize the location of the DIMMs

Thank you all for the replies. I've tried a few things, in particular the RAM voltages, without much change. I didn't run down the avenue too far for clearing CMOS or if the RAM was compatible. Given that the RAM was recognized at times, it seemed that both of these were less likely. In fact, I upgraded from one set of Corsair RAM at 1333 MHz it's virtual twin 1600 MHz version (making me thing that the slot configuration isn't at cause...my motherboard is a pretty simple setup on this issue to). Given, this and idahosurge's experience, I'm going to given the RMA a try.

You probably did that already but just in case....raise the QPI/vtt a little (baby step) and test....