Windows 7: Win 7 won't start with 4+ GB RAM

I have a computer that I built in 2007, with 2x1GB of 533MHz RAM, and I installed Windows 7 x64 RC Build 7100 on it a month or two ago. Last week I bought 2x2GB PC8500 RAM because I was long overdue for an upgrade.



I installed the new 4GB and removed the old slower 2GB, and booted up to find the Windows 7 boot screen, then everything went blank, including the keyboard LEDs, and the computer is completely unresponsive. I tried running it with one new 2GB stick and it ran fine, so i tested the other stick thinking i might have a dud, but again windows ran fine. I further tested the memory in separate bays so that it ran single channel instead of dual channel, but still nothing. The Bios always detects the memory amount correctly in setup and when booting the computer, but windows seems to hang with any setup with 4+ GB RAM. My board is good for 8GB RAM. I also reset the bios settings to default as was suggested to me, but still nothing.

I'm probably overlooking something, but for now I'm stumped. I'm pretty sure the x64 version should support 4GB. Any suggestions?

System specs would really help. Please post them under User CP.

Nonetheless - you might try bumping your northbridge voltage up one notch. (credit to Chev65).

i'm wondering if it's a windows problem at all.

when exactly in the boot sequence does the hang occur? ie do you see the animation?

have you tried booting into another os, using a linux livecd for example?

I'm not sure if you can get to your bios settings or not but... if you can get at the memory settings it sometimes helps to set the memory voltage to manufacture specs, you might want to have a look at the memory timings also to make sure they are right.

And yes, Antman is correct, with 4GB it sometimes takes a bit more northbridge voltage to get stable. But that isn't really my idea like he claims.

More of a nod.

I've installed Windows 7 on more than 6 different computer builds all with 4GB or 8GB of RAM and all of them installed just fine. Intel mobos, gigabyte mobos, and asus mobos...g.skill ram, kingston ram, corsair ram and mushkin.

There seems to be a wide range of issues in Win 7 that all have power considerations in common.

2x2GB modules shouldn't need a NB volt boost. It's a different story with all 4 dimm slots filled though.

As chev65 mentioned, input the ram manufacturers specs for voltage and timings in the BIOS manually and then run memtest86+ to check for any errors.

Memtest86+ - Advanced Memory Diagnostic Tool

Sorry, was out for a bit, but as far as memory voltage, my bios settings have a max of 2.1V and the memory itself is labeled 2.3V ... also a full length memtest with all 6GB installed ran without issue, and there was nothing wrong. As far as memory timing, i was disappointed to find my bios maxes at 800MHz (i suspect this is hardware limited, not software), though it is PC-8500 DDR2.

Antman: I'm not sure if the Memory Voltage = the Northbridge voltage, I'm not sure what exactly the northbridge and southbridge connect, I'm more of a software guy than a hardware guy. I know there are four voltage settings aside from the memory, but i couldn't tell you what did what, so I've never messed with them... I'm not exactly a seasoned veteran of computer building, i pretty much know where to plug what and that my PSU is probably stressed by my system.

I'm getting as far as the "Windows is starting..." screen with the animation and it goes to black, which it normally does before the mouse pointer appears a few seconds later, but the system hangs on that black screen instead.

As far as Specs:

AMD Athlon X2 4200+ 2.2GHz
Asus M2A-VM motherboard
NVidia 8600GT 256MB gpu memory 768MB shared system memory
Kingston 2x2GB DDR2 PC-8500 (new ram)
Buffalo Select 2x1GB DDR2 PC-5300 (old ram)

I'm probably going to be getting a new motherboard soon, so for now I'll just run with 2GB of the new ram. Ubuntu and DamnSmallLinux both detect and use all 6GB when I have them in, so I know its something with Windows 7 that is probably having driver or compatibility problems with my setup.

Edit: I bought the ram as two individually packaged single 2GB sticks, I don't know if that is any different than a 2x2GB "kit", but even so when the ram was placed so that it ran two individual single channels and as one dual channel set, or even with the 2x1GB set and 1 of the 2GB modules, windows never got passed that screen unless I had 3GB or less installed. Dunno if that is relevant, but I guess its good to say.

Had the same problem when upgrading my memory; so I put my installation disc in and ran repair (just to see if that would do anything). It worked. Now not saying it will work for your system, however, what have you got to loose.