Windows 10 feature update with old Nvidia display adapters, solution to black screen hangs

Microsoft is delaying Windows 10 2004 on computers that have old Nvidia display adapters.  This is a step in the right direction.

In fact it is possible to run Windows 10 on computers that have some old Nvidia display adapters, but it takes some effort.  I have some Dell Precision M6500 workstations with Nvidia Quadro FX 3800M and FX 2800 M controllers (sometimes designated NB10E).  Driver 342.01 can be downloaded from Nvidia's web site.  It takes some effort to make the driver stable, which I will discuss below.  Dell's web site provides 189.21 for Windows 7, designated as ISV certified, whose meaning I don't know but it was more stable than versions that came later, except that it occasionally caused BSODs and it had security holes.  Nvidia continued developing the Quadro driver for several years but didn't do enough testing.  Dell doesn't care, why should Dell care about peons who buy such cheap low class throwaway PCs?

Anyway, these models of Nvidia display adapters had a feature built into their hardware called PowerMizer.  When the PC is idle, the chip operated min minimum performance, maximum stability, low power mode.  When demands became more active, the chip switched to medium power or high power mode, but the chip couldn't handle the transition, so the screen turned black.  Dell's forums and some other sites have lots of discussions of M6500 screens turning black under heavy load.  To add to this, the driver couldn't handle the hardware crash.  Instead of resetting the display adapter like Microsoft learned to do in Windows 7, Nvidia's drivers crash the rest of Windows.  The keyboard and mouse become non-responsive, though you can see the hard drive lamp continue flashing for a while until some part of Windows settles down.

Very old Nvidia drivers (older than the ones we're discussing here) provided a GUI control panel where users could manage PowerMizer options to try to improve stability.  Nvidia stopped offering PowerMizer Manager a long time ago.

A third party stepped in and provided a downloadable PowerMizer Manager tool.  They recommend that users set PowerMizer to medium performance so the chip will never try to switch power levels, and disable detection of overheating.  I'm sure these settings stabilize the chip and driver and Windows, but I'm more cautious.  I use PowerMizer Manager to set PowerMizer to minimum performance and I do not disable detection of overheating.  When I install Nvidia's driver 342.01 and use PowerMizer Manager this way, my computers do not suffer black screen hangs.

Now about Windows 10.  Some feature updates of Windows 10 preserve the registry settings that were added by PowerMizer Manager.  However, some feature updates delete the registry settings.  After deleting the registry settings, when the Windows 10 feature update installer reboots the PC, you get the black screen hang at the time when Windows tried to display its message about do not turn off your PC.

Therefore one more step is needed.

When starting the feature update, of course you want your PC plugged in as well as having the battery fully charged.  But after the reboot, when Windows is about to let you log in, pull the plug.  When running on battery, the Nvidia chip will refrain from trying to switch to high power mode.  If your battery is still good enough, it will let you reach the point of logging in and running PowerMizer Manager to set the necessary registry entries again, and reboot.  At that point you can plug your PC in again.

So, there is a way that Nvidia or Dell could stabilize the Quadro FX 3800M and FX 2800 M chips enough to solve the black screen problem, at the cost of lower performance which we have to do anyway to avoid the problem.  But again, why would Nvidia or Dell care?

Now, surprise of surprises, Microsoft says they're working on the problem.  After several rounds of Windows 10 feature updates reinstaing the problem (though some feature updates didn't reinstate the problem because they preserved the necessary registry entries), now Microsoft says they care.  So, it would be possible for Microsoft to preserve the registry entries that are set by PowerMizer Manager.  It would even be possible for Microsoft's Windows 10 feature update installer to create those entries all on its own, to improve Windows 10 reliability on computer that have Nvidia Quadro FX 3800M and FX 2800 M controllers.  I don't know if they'll really care, but it's interesting to see an announcement saying they care.

Meanwhile, this posting tried to explain how we can deal with it ourselves.