If I install this driver as recommended by Avid for MC 8.2.  Whether I use the installer from Avid, or from the NVIDIA driver site, the following occurs:

1. install appears to go normally,
   
2. After installing the NVIDIA control panel shows correct rev info
3. I can run MC 8.2 apparently with no problems (only opened a project, played a timeline)
4. Upon reboot, I get "Unexpected_Kernal_Mode_Fault" followed by a number of failed boot attempts until I get the repair options.

The only way I could fix this was to find my way to a safe-mode boot, then uninstall the 340.80 driver.  After reboot, the "new hardware found" wizard installs the 340.52 driver (the one I had installed before the MC 8.2 install).  Aside from the "incorrect GPU Version" annoyance screen, MC 8.2 seems fat dumb and happy.  No more kernal mode faults.

Anyone else having this problem? Found out how to fix it?

Did you reboot the computer after installing 340.80? I seem to recall reading this was recommended even if there was no Must Reboot prompt during the install.  Also follow the driver setups as suggested in the Readme

FWIW I did that and it works fine here with W7 SP1 and an older 2000 card.

As a matter of interest I also had an issue with that driver.

I installed on my Z800 the 841.05 with MC8.2 and all is well.

Cheers, Radman.

I´ve done clean installs removing everything old, it´s under the advanced install options.

If it crashes, just install again, same way,  after a reboot

Yes.  That is when I hit the first Win 8.1 BSOD.  Researching on the Web i found that the only peice of data for which there is documentation is a  parameter that indicates a double-fault (two kernel faults that cannot be resolved serially).

I even tried booting to safe mode, uninstalling the driver, booting to safe mode again, running the install (tried it both with defaults and "clean") and the first reboot (wheather from warm restart or cold power up) I have to go through the series of BSOD fault screens to get to the auto-repair boot before Winddows will open.

After doing other diagnositcs, I find no hardware issues.  The web research indicated that if such was the case, then the fault(s) were likely related to faulty kernel mode drivers, and I believe the NVIDIA software attempts to install at least 2 - one for display, one for audio.  I saw additional errors in the event log related to Windows Media and Creative's audio drivers so I might try the install again with custom settings, and simply leave out installation of the NVIDIA audio driver.

The other thing I have to do is peruse the registry to see if there is some kernel mode stack or memory allocations that might be getting overrun with the 340.80 driver installed. According to web research, that may also be at play.

AndrewAction:

Did you reboot the computer after installing 340.80? I seem to recall reading this was recommended even if there was no Must Reboot prompt during the install.  Also follow the driver setups as suggested in the Readme

FWIW I did that and it works fine here with W7 SP1 and an older 2000 card.

Problem solved (I guess the 8th time is a charm...).

This time, I used msconfig to boot in "Diagnostic Mode".  Once in that mode I ran the installer which I had moved to the desktop.  After removing the older driver I had installed, the install of 340.80 failed.  So I restarted.  When windows finished booting, I tried to run the installer again.  This time I got the "... terminate New Hardware Wizard then continue..." message.  Apparently 8.1 detected the Quadro card with no driver and took it upon itself to install a driver.  

By waiting a few minutes - for the "New Hardware Found" wizard to complete - the manually inititiated 340.80 install then proceeded on its own with no further intervention from me.  Low-and-behold, on restart, no BSOD, 340.80 was installed and operating.

However, this did cause an AppMgr Error 5 situation which was easily corrected by following the advice in this thread:

http://community.avid.com/forums/t/130912.aspx

I spoke too soon.  Everything was fine while the machine was not powered down. I.e., after the 8th attempted install, as long as all I did was warm restart, everything was fine.  As soon as I powered down, then tried a cold restart - "Unexpected Kernel Mode Exception" once again.

Looking into this deeper there are two possibilities:

1. Since the Quadro 4000 and Sound Blaster X-Fi Titanium card seem to share IRQ 3, during a cold boot their competition for a common IRQ may be causing the problem although neither driver reports the other as a conflict.
   
2. The restart / reboot after any attempt to install an NVIDIA driver later than 340.52 shows my RAID 10 array as either "encrypted" (which it is not), "Verify" (meaning it is either undetectable or indicates an ettor preventing the volume from being readable) or "*" meaning it cannot figure out what the RAID disks really are.

The second possibility indicates a conflict with either or both the LSI RAID controller or Intel RAID manager.  That also explains why Avid Application Manager delivers "Error code: 5" after any attempt to install NVIDIA driver 340.80 or greater, and requires deletion of files in the SWF and Licences directories to get back to "normal".

Since the NVIDIA 341.05 release was to correct "incompatibilities with some workstation software" it is possible that older HP z800 / Quadro 4000 just cannot run NVIDIA drivers beyond 340.52.

There is alway poetry.

I told you in my earlier post.

I have exactly the same system with Quadro.

If you continue without resolving your issue

with Nvidia drivers, two options, get hold of

10Bit unistall ( the company ) they have fancy

stuff to clean the Nvidia driver and not like that

other stupid stuff you can buy or the other is to

reinstall your system software. It never stops!

Cheers, hope you get resolved. Poetry!

Radman:

If you continue without resolving your issue

with Nvidia drivers, ... get hold of

10Bit unistall ( the company ) they have fancy

stuff to clean the Nvidia driver

Which company - NVIDIA, PNY, or Avid?

I've been playing some more with this, and I could update as far as 320.66 without trouble.  Anything later and its BSOD.  I even tried the uninstall driver from device manager and all it did was prevent the 320.84 installer from running ever again.  (As soon as you execute set-up it says, "Driver Installation Failed".)

I contacte PNY asking for the "complete removal" utility you mentioned.  Instead of a straight answer (i.e. pointer to the utility or a "we don't have one", I got the standard Tech Support run-around, that required de-installing the card, all the drives that make up the media RAID, and various other useless tasks that are really designed just to piss of single (low-life) users so they leave tech support alone to massage the egos of corporations and power users.

After complying with all their bullcrap debugging tasks with no relief, and pointing out that, since the issue occurred between the transition from 340.66 to 340.84, the simplest way to solve the problem would be to look at the code that changed.  Of course, a sensible approach like that is not to be undertaken unless one is representing DOD, HP, Microsloth or some other "prestigious" organization.  Individual users are just to be run in circles, given useless "diagnosis and debug" tasks until they give up an go away.

Anyway, after pointing out the easiest path to solution (i.e. look at the frigging code) PNY support went dark. NVIDIA never responded to support requests.  PNY / NVIDIA is clearly in the "Too Big To Care" league now.

OTOH, when problems occurred with the registration / activation of a 7.0x to 8.02 upgrade, Avid support was prompt, nearly painless, and effective.  Totally new experience for me with Avid Support from the mid-90's to late "oughts" (except when I had to invoke the "Marianna Factor" - she saved my butt several times during those years when "Avid Support" was an oxymoron).