So, I left PD 15 running until tonight. RAM usage was up to 650 MB, so I decided to close it and restart it to see what would happen.
Well, it took a long time to start, couldn't find the CL driver, and said something about using an Intel integrated driver Instead, although grayed out. (I have an AMD CPU.)
I rebooted Windows, started and closed PD15 a few times to see what would happen. For this short test, with nothing else running, it started fine.
Then I noticed something called RichVideo64 running. All the time. Even when PD was closed.
A search on the Net took me to a CL FAQ from PD 14 about RichVideo being an optional service that could be enabled/disabled in Preferences. If it's an option in PD15, I can't find it.
So for now, I've set it to "Manual" in Windows Services.
In the meantime, I see that someone else just posted aboit this Intel integrated video. So that led me to someone else's fix for this Nvidia CL thing.
It says to install a 3rd party app called Nvidia Inspector and point it to Power Director.
I think this problem started after I installed a bunch of Microsoft updates in November.
I think, in January, I will install Win7 fresh and start over with a clean system.

Quote Running PD 15, v 3424. ... Win7 ... my GPU. (GTX 960, latest driver.) ...

well, may i GTX960 Performance Comparisons and click on the PC Perf Stats . i don't use 'latest driver' because PD is nVidia gpu driver sensitive... all the previous drivers listed on the pc perf stats will work with HA. i am still using 365.10 WHQL driver. PD14 will use up to 8GB system RAM...

happy happy joy joy
PepsiMan
'garbage in garbage out'

I disabled the Superfetch service in Windows. So far, PD15 is loading fine and has remembered my GPU.
I'll post if this didn't solve the problem long term.

If Superfetch was the problem, it wasn't the whole problem.

At first, PD15 remembered that my GTX960 could do OpenCL HA.

But after letting Win7 run for a few days, I tried running PD15. Unfortunately, the old behavior came back. Took about 15 seconds to start PD (usually takes seconds) and it forgot that I had OpenCL.

It's starting to seem like it has something to do with time. Or perhaps it has something to do with another program running beforehand that grabs control away from PD?

don't know if this will work... have you tried with whql driver version 365.10 or 378.88 ???

happy happy joy joy

PepsiMan
'garbage in garbage out' 'no bridge too far'

Yashica Electro 8 LD-6 Super 8mm
Asrock TaiChi X470, AMD R7 2700X, W7P 64, MSI GTX1060 6GB, Corsair 16GB/RAM
Dell XPS L702X i7-2860QM, W7P / W10P 64, Intel HD3000/nVidia GT 550M 1GB, Micron 16GB/RAM
Samsung Galaxy Note3/NX1

Quote don't know if this will work... have you tried with whql driver version 365.10 or 378.88 ???

I am currently using 388.71. I suppose I should drop back to 378.88 to see if this problem follows the driver or not. Tnx.

Another clue: When PD forgets my GPU, it also forgets the import file location that I've set in Settings. It's like PD stops reading an .ini or parts of the Registry after a while.

So maybe this is a problem with my Win7 setup, which I have severely hacked using ntlite (for security purposes).

I have tried a bunch of things over the past few months to stop this problem, but I've not had any success. (I couldn't drop down to nVidia driver 378.88, as sugggested by PepsiMan, because the nVidia archive page only goes back a year. IIRC, this problem might have started when nVidia changed their drivers to add Telemetry. Even if it is an nVidia problem tho, I would expect CL to work around it, since the the latest nVidia drivers are very popular.)

So to highlight the problem so that perhaps others might notice it and then we could combine our efforts to write a support ticket, here is a short video showing the problem with PD15 forgetting after a day that I have a GTX 960 GPU.

jmp.sh/FQICvy0

A liitle more data for detective work on this problem.

I refreshed my Win7 and repatched it. I use WSUSOffline Updater, and this time, it gave me fewer patches than last time.

That sometimes happens with WSUSOffline Updater as the community there finds patches that didn't work too well and removes them.

Since then PD15 has been working much better, although I haven't left my system running for 24 hours which seems to be the trip point for when PD forgets my GPU.

But to my clue:

I am running a Degrag program on another drive in my system. My defrag program doesn't use a lot of CPU cycles. But it does slow down drive access quite a bit. So when I started PD15 while the defrag was going, it took a long time, like in the second half of my video, above.

I thought that PD would forget my GPU and gray out the Hardware Box as it always does when PD is slow to start.

But to my surprise, I got a new message!

This one had a hardware box clicked with CUDA on it!

But then, after pausing the defrag program and starting PD15 again, this time it got my GPU right and the Hardware box was checked with OpenCL.

So after finding this clue, I'm gonna guess that there's a race condiciton going on with the GPUUtility.exe, where, if it doesn't complete in time (for whatever reason) then PD15 defaults to some lower form of GPU functionality.

However, more of you need to report here if you're having the same problem before I can write up a Ticket about this.