Can we get some deets on what's different about the two versions? Is code written against the old version going to be broken? Getting my windows 10 to update correctly has been a strange unexpected nightmare.

Can we get some deets on what's different about the two versions? Is code written against the old version going to be broken? Getting my windows 10 to update correctly has been a strange unexpected nightmare.

If the case is like we discussed previously, Microsoft eventually scrapped the behavior they believed "most people wanted"?

I wish to to see an official statement from Microsoft regarding that fix.

Previously, the swap effects exposed by D3D12 were focused more around efficiency than raw performance. They remove copies, but removing copies means adding synchronization. This synchronization is done with the desktop compositor, which runs at the monitor refresh rate. So, this synchronization amortizes your framerate to the monitor refresh rate. Less memory usage, fewer copies, but also lower throughput.

We did work between 10240 and 10586 to enable the compositor to support both the efficiency scenarios and the performance scenarios. We're oscillating a little bit while we find the perfect balance, so you may find default behavior changes on recent insider flights, but the end result is for this to be a controllable piece of functionality of the swapchain: you can either present all the buffers in your swapchain once per VSync and have the system pick the newest one, or you can present at an unthrottled framerate, which might require tearing if your buffers can flip straight to the screen.

The video I did last year alludes to this change coming:

Previously, the swap effects exposed by D3D12 were focused more around efficiency than raw performance. They remove copies, but removing copies means adding synchronization. This synchronization is done with the desktop compositor, which runs at the monitor refresh rate. So, this synchronization amortizes your framerate to the monitor refresh rate. Less memory usage, fewer copies, but also lower throughput.

We did work between 10240 and 10586 to enable the compositor to support both the efficiency scenarios and the performance scenarios. We're oscillating a little bit while we find the perfect balance, so you may find default behavior changes on recent insider flights, but the end result is for this to be a controllable piece of functionality of the swapchain: you can either present all the buffers in your swapchain once per VSync and have the system pick the newest one, or you can present at an unthrottled framerate, which might require tearing if your buffers can flip straight to the screen.

The video I did last year alludes to this change coming:

Jesse, thanks for your ultimate, official, answer to this myth.

Having said, I acknowledge that it's hard to make decision on various scenarios, just like the well-known unification HW feature requirement introduced by D3D10.0, which initially sounds like a console-like revolution, but before long, as we saw in D3D10.1/11 the caps revived.

Yep, update Windows and you should end up on at least 10586. Try your app again after that.

I've installed all available updates making it "up to date" already, but it's still 10240?

It can be installed manually if it doesn't yet appear in Windows Update: http://www.groovypost.com/howto/install-windows-10-november-update-1511-manually-media-creation-tool/

Thanks Adam, but I got the info saying that Win 10 Ent users can't auto update to 1511 but download a iso ...

This is getting a bit off-topic now, but is your machine located in a workplace environment where an IT team may be controlling the update process?

No, indeed, like you said, we should stop here and I'm happy that I've got the confirmed answer.