Comment 56 for bug 1072206

@navidR

Turning off animation conserves large amounts of memory, but after opening about 50 (can't remember the exact figure) windows on a 3200x1200 dual head machine (which is not uncommon for me given my work pattern) on a 320MB video card the problem still comes back for me. As far as my extensive tests concluded, there is nothing you can turn off in compiz that fixes the problem. A particular choice of settings may reduce the memory loading and so push the problem beyonda persons practical use limit so they don't bump into the problem in normal circumstances, but the problem is still there at the same memory threshold.

The following test shows it to be a memory issue: Open windows until the problem appears. Now close windows until the problem goes away. Open one more window. As you vary the size of that window you will find a window size that is at the threshold of the problem. Make the window bigger and black windowing occurs. Reduce the window size, the problem disappears.

This, or related problems has been a known issue for many many years. Back in 2006-7, this or similar bug existed, known as the NVIDIA Black Window Bug, though whether the bug was actually a NVidia one or a compiz one was in question. The workaround was to change the direct rendering options that existed in compiz at the time. It was suggested that the NVIDIA Driver 100.14.19 fixed it. Maybe it did. If it did the bug, or a similar one was reintroduced at some stage, or something was never properly fixed. I don't know. But it is clear that this bug, at least as I am experiencing it, is memory related.