what you mean the the problem only apply to those with nvdia graphic? whats the display problem actually?
Added on May 31, 2008, 2:14 pmafter reading through the thread, as my experience, is the faulty mother board so far.
just before 2 weeks ago, i have changed with two faulty mother board, which are the A08 CN-OPU073 mobo. The reason i changed it is because everytime i turn on the laptop, the screen displayed some RAINBOW above and below the screen, also got the weird vertical or horizontal lines too when i get lucky

That time i need to press the power button again again and again in order to successfully log into the window. But if does log into the window, after few minutes, the screen distorted by some crazy colour, then the laptop shut down. This problems occured during the 1st mobo replacement.
The 2nd replacement: The same problem, but the probability of logging into window has increased, but still the laptop will shutdown automatically.
i remember that time when i watched "DIE HARD 1" with my xps, after 2 hours, the screen went blank (black), but the sound still continueosly producing. No matter what i pressed, the laptop cant even shut down. And, before that i like to turn off the window security centre. But that time somehow i turn it on, and it pop out a message, said that my display driver was uncompatible to...... i forgot already. At that time, i though is my x64 nvdia which download from tweakforce, caused the distortion and make my laptop unuseable. So, i uninstalled it, but still the problem occured.
After that, i went back to my hometown, called dell to replace a new mobo to me, this time, i strictly ask the lovely tech customer to sent me the new OD057P REV00, which strongly recommend by Dopod brother. So, after 2 days, they really sent me the new mobo with REV01. Now, the problem solve, works good. but i haven install any temperature monitoring program in my laptop. if do, i will update my temperature reading soon.
By the way, the engineer told me that my 2nd mobo actually had some burnt issue around the power supply connector there.
haiz. dell really nothing to do and find things to do la. But finally i still get a new mobo replacemnet.
So, as a conclusion, i think our 8400 works ok. cz now i currently still installed the x64 tweak force driver. works prefectly.
Hope these can help you.
and congratez tat they finally made ur machine perfect! lets cheer for dell technician support!
the 1st problem is the most common problem, this is wat they call "flaw" or something like tat. most of the oversea user face tis problem, and one of my fren too. they said it was graphic card fault, burn or something.
I'm not sure about the part where you mentioned the 8400 works ok. IMHO, most of the problems with our lappies are due to the graphics itself. Like how you get odd-colored pixels, vertical/horizontal lines, blank screen etc etc.
They replaced the whole mobo just because graphics is integrated on the mobo itself.
8400 is a discrete graphic card, not integrated. means seperated.