But I see you're already doing that, and the only reason that your windows are not rendering at the same rate is because the OS thread scheduler is not democratic, it performs poorly in terms of load balancing.
Because as I already said:
1) When using Direct3D on the same videocard, there is no issue with load balancing:
I have also done tests with just rendering the windows with a framecounter in the title bar, and no D3D or OpenGL rendering at all. The OS scheduler is not the problem.
2) I have tested on two other systems, which did not show the problem either. Even though they are slower systems, and the framerates were lower on average, the animation remained smooth because the load remained balanced properly.
So I think my comments were in line.
I don't. You were talking about, and I quote: "using multiple threads to render a single frame".
Which is the opposite of my situation: "Rendering multiple frames, with one thread each".
The rest of your post was just Captain Obvious on multithreading. I'm not sure with what intent you posted it, but if you think I didn't already know about that, you're sorely mistaken.
And this post again... If you bothered to READ my earlier post, you'd know that I had already eliminated the OS scheduler as the root cause, because, and I quote:
"This was on a GeForce GTX460
. So I figured I'd also try it on some other machines
, one with an ATi Radeon X1900XTX
, and one with an AMD Radeon HD5770
. Both ran more smoothly
the GTX460 had no such problem, so I just reported it as a driver issue."
Next time, have the decency to READ a post before you reply.