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Purchased an 8GB kit for my Lenovo T500 2081 CTO. The RAM I pulled out of it was PC3-8500. The kit I bought was the Corsair CM3X8GSDKIT1066, which includes 2 4GB SODIMM's. When I put them in, the BIOS recognizes them - 8192 if both are in, 4096 if I try just one. However, Windows 7 refuses to boot with them in. I get blue screens - something about IRQ NOT EQUAL?

I have two different machines, both do the same thing.

Is the RAM just not working, or is there some basic compatibility problem that I'm missing?


I've downloaded memtest86 and run it against both the old RAM and the new RAM. The one thing that really stands out is that the old RAM is dual channel, the new RAM is single channel. The other thing that stands out is that both of the new RAM sticks will report various random errors in memtest86. Wondering now if its important that I buy dual channel...


I also just tried updating my BIOS. No dice.


  • Memtest86 reports that both of the new SIM's have errors. Don't know if this is incompatibility, a bad run at the foundry, or bad luck.
  • At one point, I did get the system to boot with my old 2GB and one new 4GB, got in to Windows, but as soon as I launched Visual Studio it crashed.
  • Memtest86 reports that the old RAM is dual channel, and the new RAM is single channel.

My next steps are to go shopping I guess, and return the new SIMs.

memtest86 on new SIM memtest86 old SIM

share|improve this question
Does it boot with only one? I am reading your question to say no, but if you could confirm, that would help, and probably rule out bad memory if neither can boot the system individually. Does it boot with only one? – KCotreau Jul 31 '11 at 4:19
@KCotreau - it doesn't boot with one or two. – Kyle Hodgson Jul 31 '11 at 14:42
See the comment to my answer below. The chances of having two bad sticks is slim. I really suspect that if you tried adjusting the clock speeds for it as in my answer below, that my comment to my answer is right, and it is just not compatible. – KCotreau Jul 31 '11 at 14:51
One more thing, its for sure pc3-8500 I double checked. Will try the timings tonight. – Kyle Hodgson Jul 31 '11 at 16:52
@kcotreau my BIOS doesn't seem to have a way to adjust the clock speeds ... memtest seems to report all the same stats with the exception of single channel vs. dual channel. – Kyle Hodgson Aug 2 '11 at 0:45
up vote 3 down vote accepted

You have two major possibilties:

  1. The RAM is bad. I would suggest using some kind of memory testing application and running it for many, many hours. Memtest86 is included on just about every Linux CD on the planet or you can burn a dedicated disc. Additionally, the Windows 7 disc will have its own memory diagnostic test that you can configure to perform up to 99 passes with.
  2. There is some piece of hardware on your system that is not addressing the memory correctly. I know of one case where a person had to uninstall many different drivers before the new memory was recognized. That included network cards and graphic cards. I would suggest updating all of your PC's drivers to their latest interations. Perhaps boot into safe mode before Windows loads and see what happens.

If you want to examine the dump file that the BSOD makes, you may find some valuable information. Check out this good thread for some insight into how to use Windows Debugger to do that.

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I suspect either it is incompatible, but I was not able to prove that 100% (see comment below), or your BIOS settings need adjusting.

To check the compatibility, you might want to call Corsair and/or Lenovo on Monday.

In the meantime, you can check your BIOS settings like this:

Put in the memory you had that worked. Then download System Information for Windows for free here:

Run SIFW and check the memory settings, in particular, the frequency and timings (especially this). Then go into your BIOS and manually set the timings to match your report. Then try booting.

share|improve this answer
The datasheet for your computer from the Lenovo site: "Memory: Up to 8GB of PC2-8500 1066MHz DDR3" Are you sure the memory you pulled is PC3-8500 and not PC2-8500? – KCotreau Jul 31 '11 at 4:25
I think that's a that's a misprint, "PC2-" is DDR2 RAM. Also, according to Kingston's RAM picker, the T500 takes a "KTL-TP1066/4G" as the 4GB stick, which is DDR3 1066 (PC3-8500). As you commented, we need to know if it boots on one of these sticks. – Ƭᴇcʜιᴇ007 Jul 31 '11 at 4:47
@techie007 Frankly, I am more of an OS guy rather than a great heardware expert, but I did google both PC2-8500 and PC3-8500 to see if both existed, and they seemingly did. That said, I would know know if there were some compatiblity issue. – KCotreau Jul 31 '11 at 4:52
Regardless, good eye on that. :) – Ƭᴇcʜιᴇ007 Jul 31 '11 at 5:34
@techie007 Thanks. – KCotreau Jul 31 '11 at 5:46
  1. make a bios upgrade on working ram
  2. make tests on new ram
    • place one sodimm -> test it, pull out
    • place another -> test it, pull out

Windows memory diagnostic is ok, memtest from Win7 boot cd is good too.

Is Your ram working properly on both banks?

share|improve this answer
good idea...... – Kyle Hodgson Aug 2 '11 at 0:45
didn't work. neither stick works in either bank. both report errors in memtest86. – Kyle Hodgson Aug 2 '11 at 1:01
so I'm pretty sure that 'brand new' rams are broken - check warranty and You should replace them where you bought them. – Adam RichardSon Aug 2 '11 at 9:16

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