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D820 screen flicker
Hello
I bought a lattitude D820 with NVIDIA Quadro NVS 110M video card two weeks ago.
I soon noticed a screen flicker every 5 or 10 minutes happening in random way. The screen seems to move a few pixels and come back again. The problem becomes very annoying when working for longtime in front of the computer screen.
Of course I have updated to the latest video drivers from Dell (version 8.4.6.9) and I have run all included video card tests
that do not indicate any error.
I have called local support who replaced the motherboard including the video card but unfortunately this did not solve the problem.
I would appreciate any help.
I bought a lattitude D820 with NVIDIA Quadro NVS 110M video card two weeks ago.
I soon noticed a screen flicker every 5 or 10 minutes happening in random way. The screen seems to move a few pixels and come back again. The problem becomes very annoying when working for longtime in front of the computer screen.
Of course I have updated to the latest video drivers from Dell (version 8.4.6.9) and I have run all included video card tests
that do not indicate any error.
I have called local support who replaced the motherboard including the video card but unfortunately this did not solve the problem.
I would appreciate any help.
Message Edited by jsozir on 11-22-200611:14 PM
- Thanks for the reply. I am not sure the problem is similar although the cause
could be common. What I see is a real shift of the entire screen image by one pixel or two and then it comes back again. I see no variation to the brightness.
The problem seems to be related to Direct3D. It can be eliminated using with NVIDIA Powermizer and selecting "Reduce dvi frequency" in the "Digital Flat Panel Settings". However in this case all applications using Direct3D do not function properly including windows screensavers like "3D Text".
My D820 has a Duo Intel T7200 @ 2 GHz with 2GB of RAM. The screen resolution is 1680x1050 and color mode 32bit.Message Edited by jsozir on 11-23-200602:24 PM
- I've seen the pixel shifting too now. I assume that both this and the backlight dimming could be caused by a DVI connection issue.Direct3D can't be the problem, it's just a software interface ant it's very likely that the problem occurs with OpenGL as well. But the underlying driver could be broken. It's certainly not a good sign that Direct3D stops working when the DVI frequency is reduced. I noticed that the driver is relatively speaking quite old, but I couldn't find any newer one on the NVIDIA site (9x.xx series instead of 8x.xx) that is compatible...I too have a Core 2 Duo T7200 (and 2 GB of RAM). It might still be the Core 2 Duo power saving that is the real cause of the issue. The DVI connection just sends data at a high frequency and is sensitive to interference. Lowering the frequency can help but it's probably better to prevent the interference itself.
- There is no bluetooth in my D820.
I think there is one way of systematically reproducing the flicker at least in my portable. When powered by battery go to "Desktop->Properties->Screensaver" Select any 3D screensaver e.g. "3D text". After 1 sec the shift is reproduced. You don't have to apply the selection just select. This does not happen with other screensavers just the 3D ones.Message Edited by jsozir on 11-26-200601:15 AM
- Yes, I'm able to fully reproduce that! This is something the Dell and NVIDIA engineers can (should) definitely take a look at!And just to confirm: It's not the bluetooth or any other internal device. I disabled pretty much everything in the BIOS and the shifting still occurs. By the way, the backlight fading I talked about is probably really the pixel shifting. The flicker is easily mistaken for a change in brightness.
- It seems I have found a way to eliminate the flicker but I do not know yet at
what cost.
NVIDIA powermizer lets you adjust power consumption. You have two slide
bars one for "AC outlet" and one for "Battery".
Each bar has three options "Maximum power savings", "Balanced" and "Maximum performance".
By default both bars are set to "Maximum performance". If you set them both
to "Balanced" the flicker disappears.
I am really confused now. Does this indicate its a power problem ? And what are the consequences in the video card performance ? Perhaps this is related to what you proposed about processor consumption. On the other hand the "dvi" stuff and screensaver Direct3D seem to point to another direction (driver).Message Edited by jsozir on 11-26-200611:07 AM
- Again a good find! It indeed appears to solve the flicker problem. Unfortunately, this halves performance. 3DMark06 gives me 695 points on 'Maximum performance', but only 349 points on 'Balanced'. So just like reducing DVI frequency it's not an acceptable fix. But at least we know it has something to do with power management.It's plausible that when the graphics chip switches between half and full power the DVI module gets a voltage drop and the pixels go out of sync for one frame. At reduced DVI frequency it can handle this glitch, and with PowerMizer set to 'Balanced' it just doesn't switch power modes...What I'd really like to know now is whether our systems are the exception, or whether every Latitude D820 with Quadro NVS 110/120 and every Precision M65 with Quadro FX 350M is experiencing this problem. Anyone with such system reading this: please try the 3D screensaver test as described above, and let us know if you see any kind of flicker.
- I recently found this: http://www.mastercam.com/Support/TechTips/backplot/Bkplot_depthbuffer.htm. I don't know whether it fixes the problem we're seeing, but it's worth a try...
c0d1f1ed
20 Posts
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Posted November 23rd, 2006 09:00
Message Edited by c0d1f1ed on 11-23-200605:55 AM