# Windows 7 - BSOD - IRQL not less or equal



## Lloyd Johnson

From what I've managed to research so far, it would appear that there are an infinite number of reasons why one's computer would crash for this error message.

I just finished a new build and I get this crash "IRQL not less or equal" along with a few others (I get the IRQL not less or equal crash most often) EVERY time i try to run the install of windows 7. Although one time I did manage to get to the install screen where you choose your language, right when I clicked install it crashed again. Another time it said something about a page fault error and another time it said something else. I just keep trying to restart my computer and am hoping it works.

I have never been able to find an answer that is unique to my specific crash reference. If anyone can answer or direct me to solution in any way I would be most grateful.



My System Specs:

Motherboard: 
GIGABYTE GA-EP45-UD3P LGA 775 Intel P45 ATX Intel Motherboard

Processor: 
Intel Core 2 Quad Q8300 Yorkfield 2.5GHz LGA 775 95W Quad-Core Desktop Processor Model BX80580Q8300

RAM: 
CORSAIR XMS2 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Desktop Memory Model TWIN2X4096-8500C5C G

Graphics Card:
POWERCOLOR AX4850 1GBD3-PH Radeon HD 4850 1GB 256-bit GDDR3 PCI Express 2.0 x16 HDCP Ready CrossFireX Support Video Card

Hard Drive: 
Western Digital Caviar Blue WD6400AAKS 640GB 7200 RPM SATA 3.0Gb/s 3.5" Internal Hard Drive

Wireless Card: 
Rosewill RNX-G300LX IEEE 802.11b/g PCI Wireless Card Up to 54Mbps Data Rates 64/128-Bit WEP, 802.1x, WPA, WPA2, AES, TKIP with 2 dBi Antenna

Operating System: 
Microsoft Windows 7 Home Premium 64-bit 1-Pack for System Builders


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## art_l_j

Hey, nice-looking system you have there!

Could you also please tell us the information about your Power Supply, suck as its power output rating (in Watts), and the Manufacturer's Name and Model Number. Thanks!

Now, getting down to the Brass tacks, here are several things that you can check:

Your problem may have something to do with this reported problem:
Microsoft details Windows 7 memory leaks, hangs, freezes

Your system's problem might be how it reacts to this memory leak bug. Anything is possible, in this type of situation.



> Microsoft has been tracking some odd issues that occur on Windows 7 and Windows Server 2008 R2. These bugs are not typically fixed via Windows Update, because these hotfixes should only be applied to systems that are experiencing specific problems. So if you are not severely affected by either of them, wait for the relevant service packs. Here are the four most prominent issues, listed in order of decreasing severity.
> 
> The first manifests itself when the computer crashes after it runs for some time ...


The 'hotfix' in the above article is not part of any normal 'Update', so you do not get it unless you specifically request it.

Have you run a 'Full Scan' with a good anti-virus product, like Microsoft Security Essentials (MSE)? You can download and install MSE for free, and in my experience (I am an OEM of custom-built computer systems), it works very well.

Next, your problem might be, that you are using an ATI Graphics card.

There have been widespread reports of ATI 4xxx and 5xxx Graphics card driver problems:



> There are 3 big categories of problems:
> 
> #1 is people experiencing 2d crashes: to these people, a good fix that seems to be working very well for most is to set your idle clocks higher (most suggest 400MHz for core and 900MHz for memory, but any value between that and 725/1000 should, in theory, be fine.
> 
> #2 is people experiencing 3d crashes: to these, it's a little bit more complicated. A lot of people had success by setting the voltage higher, or downclocking the core and memory for more stability. It certainly is a more complicated problem than the 2d crashes.
> 
> #3 is people (like me...) getting both. In this case, as far as I know, the only thing you can do is severely downclocking your core and memory in order to get more stability, but still... there are crashes (less often though...)


Full Article:
Radeon 5xxx Owners Report Grey Screens/Hangs



> A significant amount of ATI users have taken to the AMD user to user forums to complain about grey screens, crashes and colored-striped hangups.
> 
> (There's actually countless forums out there with threads like this – including at least 4 threads in our own forums. I'm concentrating on the AMD forums because these guys, between them, have collected nearly 40 pages of possible causes involving everything from Windows, to mobos, to RAM.)
> 
> So far it's unclear as to what is causing the problem. Users report that grey, brown or colored stripes/screen appear while playing games, watching movies and in some cases, while idle. The problems seems to be confined to the HD 5xxx series, although there are a couple of mentions of 4xxx cards.


One thing's for sure, there's a serious problem with the lineup; and so far ATI/AMD haven't stepped up to the plate to take care of it.

[The above was copied from a user's Post at PlanetAMD64, where I am a member.]

I think that this 'ATI Driver bug', is worth looking into.

*[UPDATE]* So after huge amounts of forum trawling, we're seeing the following model numbers crop up again and again: 4770, 4850, 4870, 5770, 5850 and 5870. The cards seem to be coming from all different companies; the following are the ones we've seen crop up more than a few times from different users: XFX, Sapphire, Diamond, ASUS and HIS.

Your graphics card, the Raedon HD 4850, is in the above list, of cards that have had serious problems with bad driver software.

Also, something that I always try, [almost] regardless of the actual computer's failure symptoms, is a known-good power supply.

You should also determine if your power supply is under-sized for the total load that your system puts on it. Generally, you should estimate the total power consumption of your whole system, and then *multiply this number by at least 1.5,* to get a 'safe' total power output that you need, in your power supply's specifications.

A power supply that is undersized, or is putting out incorrect voltages, or that has a lot of AC noise on the DC outputs, can appear as almost any problem under the sun. Even a brand-new power supply, from a reputable manufacturer, can be bad.

Power supplies today are so inexpensive, that I always have a selection of various sizes on-hand at all times (it helps that I am an OEM of custom-built computers).

Something else, that often fixes 'unstable' machines, is to [when the power is off and the computer's case is open] basically un-plug (disconnect) and re-plug (connect) all connectors, RAM (DIMM) modules, the CPU chip, etc. You should be sure to do this (un-plug and re-plug) on *every connector* that you can see, inside your computer.

It is surprising, how many 'weird' problems can be traced to a simple 'the connector was not fully plugged in' type of problem.

One more thing, is to make sure that your RAM size/configuration/part number, is supported by your Motherboard's 'Qualified Vendors List', or 'QVL' for short.

In ASUS Motherboard manuals, the QVL will be in the section describing how to install the RAM (DIMM) modules into the Motherboard.

For example, in the ASUS M4A79T Deluxe manual (I have 2 of these Motherboards), the QVL is in Section 2.4.2 'Memory configurations', starting on Page 2-12.

Also, because you have multiple RAM sticks (DIMMs), try installing just one at a time, in your Motherboard, to see if you have a bad one. Look in your Motherboard's manual, to see which socket (nearest or farthest from the CPU) is recommended when only one DIMM is installed.

You should also 'un-install' your graphics card driver, and then reboot your computer. Windows will then detect the 'new' hardware, and automatically find and install the 'best' driver for your graphics card.

I hope this helps,
Art


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## jcgriff2

Hi - 

Please follow these insructions --> BSOD Posting Instructions

Regards. . .

jcgriff2

.


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## Lloyd Johnson

Thanks for replying to my post, its much appreciated.

Sorry about not posting my power supply, i didn't realize is was all that important. 
Anyway here it is: 
APEVIA ATX-AQ700W-BK 700W ATX12V / EPS12V SLI Ready CrossFire Ready Power Supply

So I tested the both of the RAM sticks by trying to run the installer with only one of the cards in but i still get the error each time, so that problem is out. I will run memtest86+ on my system tomorrow to be sure my RAM is not the problem. 

I will also try to run the installer with the video card from my old PC and see if it works. This will let me know if the problem is with the graphics card. I will post tomorrow with the results. 

Also, i heard that the problem could be the result of a faulty hard drive, any light you could shed on that subject would be appreciated.


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## art_l_j

Hey, Thanks very much, for the excellent hardware information that you supplied, on your computer system.

Here is a link, to the Qualified Vendors List (QVL), for your Motherboard:
Qualified Vendors List (QVL)

This is your RAM's part number:
CORSAIR XMS2 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 1066 (PC2 8500) Desktop Memory Model TWIN2X4096-8500C5C G

Now, here are the *only two* Corsair DDR2 1066 (PC2 8500) RAM sticks, that are on the QVL for your Motherboard:
Corsair CM2X1024-8500C5D
Corsair CM2X2048-8500C5D

So, I'm sorry to have to be the 'bearer of bad news', but your Corsair RAM part number is not listed in the 'QVL' for your Motherboard (close does not count, unfortunately).

Therefore, I would like to very strongly suggest that you should return the Corsair RAM sticks for a refund, if possible, and buy one of the listed part numbers in the 'QVL'.

I hope this helps,
Art


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