Blender supports 4 different swap-buffers methods. The best future proof method is to use triple-buffer, which draws off-screen, and copies that buffer to the visible screen. This allows overlays (like menus) to draw fast, and some day we will even do cool compositing effects efficiently then. Unfortunately triple-buffer is not working everywhere, especially on Intel graphics cards it seems to be slow.

A standard ‘swap buffers’ on graphics hardware can work in two ways:
– Swap-copy: (copy back to front buffer, most graphics cards do this)
– Swap-flip: (exchange back and front buffer)

To my knowledge it is impossible to find out out which method a card uses. Currently, for Intel graphics we assume “Swap flip” is default. But bug reporters in the tracker make me think it’s the regular “Swap copy”.

You can test this (default startup) in Blender easily:
– Start Blender
– Press M (move to layer)

If your buffer swap method is wrong, the “Move To Layer” menu flashes away immediate. It’s still there, but invisible. Click a bit around to close it, and a 2nd M-key makes it appear. Move the default cube to another location, and M-key goes bad again.

Now change User Preferences -> System -> Draw Method to “Overlap”. And test again. Does M-key work OK now?

Also: try “Triple buffer”. Is this really slow or not working at all?

Some Intel graphics card owners also mentioned that opening a 2nd window (like user preferences) hangs. You can bypass it by opening the User Preferences with the left-most menu in every header in Blender.

Report your findings here please! Especially for Windows and Mac. I’m also very curious to find out if official information on this topic exists even. BTW: for Linux, the Intel gfx drivers already support both methods, and they default to “swap copy”.

UPDATE: Fix for crash when opening second window (User Preferences, for example) had been just commited to SVN  (rev. 36070). There could still be issues at multiple video card configuration, but this shouldn’t be a big problem, because most of Intel video cards are installed into notebooks and netbooks which have only one video card. If you don’t build Blender yourself,  we already got updated Win32 build here. We haven’t got Win64 nightly builder yet, so for this platform you should wait until there’ll be new builds at graphicall.

Thanks,