Screen artifacts and memory parity error

Question

I have owned a Dell Inspiron 9400 laptop that has given me nothing but grief. I bought this laptop in 2006 and over the near year (till 2007) dell replaced the motherboard twice, LCD screen once. But the LCD artefacts (like below) kept appearing. In 2007 I gave up and threw the laptop in the closet.

Last month, I took this out and got Dell to give me a replacement motherboard again (yes after 4 years and without any charge). After 10 days of using the laptop, I have started getting the artefacts and memory parity errors again.

This makes me think that there is something different going on with this laptop, and would like to diagnose the exact issue with this laptop. It seems like the problem is with RAM now.

What I am looking for is a guide or a set of tools I can use to correctly diagnose the issue once and for all. I want to consistently reproduce this error.

This is the error I got today morning, please note that once I reboot the laptop, it will work find till an indefinite period of time (usually few days).

System Specs: http://supportapj.dell.com/support/edocs/systems/ins9400/en/om/specs.htm

OS: Windows 7 Ultimate SP1 - with latest drivers for all components

EDIT: Probably worth nothing that:

I have already run the ultimatebootcd memtest with no issues detected. I have also run the Win7 memory test thing with no issues. I have also done the following to head generate heat:

1. Run PC Marks for 1 hour (keeping laptop near the GAS heater)
2. Played a full HD (1080p) movie using VLC for over an hour

Answer 1

Based on your link, it looks like you could have any number of video cards. It can't be a problem with the integrated video if that is what you have since the motherboard has been replaced so often. What video card do you have? If it is one of the discrete graphics cards, has it ever been replaced?

It could also possibly be your memory, so I would download the Ultimate Boot CD and run Memtest. http://www.ultimatebootcd.com

One last component that comes to mind is the video inverter card. This is not a component everyone has heard of, but it is important to your laptop's video. Go Google "video inverter card" (minus the quotes), and you will see that they are quite important.

I would also not overlook over-heating as a cause. Do you blow out the exhaust ports near your processor fan on a regular basis?

Answer 2

This makes me thing that there is something different going on with this laptop, and would like to diagnose the exact issue with this laptop. It seems like the problem is with RAM now.

The error may show as a memory error, but screen corruption like this is never directly caused by memory errors. Memory parity errors may in fact have nothing to do with memory itself (in the sense that memory chips may otherwise be perfectly fine) but instead be generated by external causes, like heat or other components directly attached to the mainboard.

In any case, rest assure the screen corruption isn't indicative of a memory error under any circumstance, which in fact generates a BSOD. If anything, the parity error you see displayed on the screen is a consequence, not the cause, of a deeper problem in your hardware. Not to say that you may not have issues with your memory. Depending on the gravity of the situation (see below), your memory may also start to be affected. But it's not the cause.

What I am looking for is a guide or a set of tools I can use to correctly diagnose the issue once and for all. I want to consistently reproduce this error.

Unless you have deep knowledge of laptops internals and are willing to dismount yours, you will not be able to achieve the type of information you want and any attempt at telling you what the exact problem is, is an exercise in speculation.

There's however something you need to know:

These type of problems happen often to laptops with motherboards that have poorly soldered components, or that otherwise fail easily to heat conditions. The laptop may not even show signs of overheating, but the components are either defective, of poor quality, or badly soldered which makes them more sensitive to heat or reduce their stability.

It's irrelevant to you exactly which component is having issues. It is a component attached to the mainboard and there's nothing you can do to replace it. They need to replace the motherboard with a working, non-defective one.

Because your supplier has replaced this board twice already, I'd suggest you don't be so gentle with them anymore. Either they are lying and replaced nothing, or they are replacing a defective motherboard with another defective motherboard... until your warranty expires. It's just simply that once replaced the problem is meant to go away. For good. Not to return within days. So you are being badly served by your supplier and it's time you take action.