CPU causing jittering in 3d apps.

Ok, so this is the wierdest problem I have EVER seen, and I have seen alot of crazy computer problems.

I have a latop (Fujitsu Lifebook N3010) that has been a loyal machine for over three years. As its warrenty is up I decided to finally open it up and do some cleaning since the fan grills were pretty filthy. While there I also cleaned up the CPU and installed some nice artic silver which lowered my temps quite a bit (not to mention the noise level finally).

Fast forward a month of flawless performance and while I am playing a game my screen starts to litterly jitter, with pixels being randomly adjusted about, seemingly the jitters all start on a edge, so if I have a rectangle showing, its the endges that get blurred while the middle stays relatively normal, except for text which also goes crazy.

At first me and a friend figured the video card was the problem. Opened up the system, isntalled a better cooling system, but low and behold nothing was helping it. Some testing showed that not only did the jittering not effect performance, but that when I used a CPU burn in program I could actually make it stop. Some how fully loading my CPU removed the jitters, of course this made game performance awful and so its not really a good solution.

A google search found a thread with another person having the same problem with a CPU almost identical to mine (2.66Ghz P4 instead of my 2.8Ghz P4). Turns out when he swapped procs, no more jittering, and later he found a hair among the pins. So last night we opened it up and clean the cpu area, made sure there were no hairs, but still jittering when ever 3d apps are run (anywhere from flower box screen saver to any games). I even got the issue with a linux live cd and running a simple OpenGL pinball game. So its not software specific at all.

We are going to swap out the CPU tonight (friend works at a comp repair/build shop and so we can get one to test with), and see what happens. But has anyone ever heard of such a bizarre behavior before? Its just so random that the CPU freaks when doing 3d/high level math work, but is still completely stable, my games don't even lose FPS when going garbled. Nor does it make sense that putting more work on the processor would fix the issue.

I'll let you know how the CPU swap goes, but this is seriously bizarre stuff.

 

Welcome to MajorGeeks! And dang, that is a strange problem. Let us know how it goes with the CPU swap.

E

 

Well CPU swap didn't fix the issue, I think whats happening is that some of the ram on the videocard is either A: not getting cooled enough, or B: already bad and I am FUBAR.

This isn't good since I am looking at taking this laptop with me to China for the next two years, DOH!

Anyone know a program that can do a memory check on Video ram? I know there is lots out there to test system Ram.

Sigh, if only laptops were designed to have interchangeable video cards.

 

I agree your problem is hardware based. There are a lot of areas you may have looked into but haven't reported.
Not only can the processor get intermittently poor connections but so can the system memory, take it out and clean it and reseat it. Try substitution.
Does turning off video caching (shadowing) in RAM (in the BIOS) make any difference?
Like the guy with the hair, foreign material can cause a partial or parasitic connections across board tracks an components. Examine carefully and clean. I use an airline and blowpipe.

Studio T