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I bought a MacBook Pro earlier this year (Early 2011 model), with i7 and 4GB RAM (2 x 2GB). This was to be used as my work computer, running Windows 7 most of the time. This setup has worked great and I had no troubles using the Windows-on-Apple approach.

Rather than buy the expensive 8GB upgrade from Apple at the time, I decided I would upgrade the RAM later, when memory became a problem.

So yesterday that time came, and I bought 2 x 4GB dimms (Hynix PC3-10600S 1333mhz DDR3 204pin) to replace the original RAM. and carefully installed these myself. The new RAM is the exact same brand and configuration as the original RAM, except twice the capacity -- bought from a reputable Apple supplier.

After the installation, Mac OS X seems to work perfectly.

Windows 7, on the other hand, BSODs within two minutes of startup... every time. Any programs that I manage to run crash within seconds, and eventually this results in a BSOD (either IRQ not less or equal, or page fault).

Any ideas why more memory would work in Mac, but fail in Windows?

(I've since changed back to the original RAM, and this works fine in both OSs).

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I've seen this random behaviour before. Can you replicate with just one of the RAM sticks at a time? You might also just have bad luck and in that case, see if 6GB will work (1 x 2GB and 1 x 4GB). – user3463 Jul 19 '11 at 4:55
Is your Windows x64? If not, you should use Windows 7 64-bit for 4+ GB support. – Fábio Perez Jul 19 '11 at 5:50
@Fabio - I thought Boot Camp only offered 32-bit drivers? – TuxRug Jul 19 '11 at 6:16
@Fabio - Yes, the Windows 7 is 64-bit. – mrcrowl Jul 19 '11 at 8:33
@Randolph: Thanks for the tip. I tried using just one of the sticks with one stick of the original RAM and it worked fine in both Windows and Mac. Tried the other new stick in the same way, and it crashed and burned in both OSs. Looks like it was just bad RAM. I'm guessing I don't get a crash in Mac OS because it hadn't addressed into the second – mrcrowl Aug 2 '11 at 8:58

@TuxRug and just for the record for whoever reads this on Apple's Support site they mention regarding Leopard 10.5, Snow Leopard 10.6 and Lion 10.7:

"...certain Intel-based Macs via Boot Camp...The only 64-bit version of Windows supported on these computers is 64-bit Windows 7 Home Premium, Windows 7 Professional, or Windows 7 Ultimate."

By certain I'm guessing it means the newest hardware.

Along with OS X Lion I'm using Win 7 Ultimate on a Macbook Pro uisng Bootcamp with 8GB DDR3 (and an SSD if that matters) but no crashing or odd behaviour other than a few driver issues; screen brightness when on battery and Bluetooth Magic Mouse problems.

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Perhaps you are using a 32-Bit version of Windows 7. This supports only up to 4GB of RAM. You will need to get a 64-Bit version of Windows.

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