> each with 5 tabs

Tabs only affect RAM, not VRAM. When I open tab after tab and also load pages in them my amount of free VRAM does not decrease. This is with Enhanced Display enabled.

> I am not asking how to limit the problem

And I'm not telling how to limit the problem but just replying to your "no matter what mode" statement.

> I'm asking why it happens

But does "it" even happen with Enhanced Display disabled as you suggested?

Quote:

Because the system swaps huge hunks of mem between RAM and VRAM without AGP mode implemented. From what I know this should be fixed in next release (2.8?). As for now - you can either switch Enhanced Display off or switch to a better computer.

I think a good idea would be an option where the gfx system avoids VRAM to RAM (but not RAM to VRAM) copyings altogether. What this means is that basically all bitmaps (especially window bitmaps) will be in RAM (and all gfx operations in it software rendered). This bitmap buffer in RAM will never go away. At any possible point the gfx system may "attach" a real VRAM bitmap to the RAM bitmap. The two bitmaps are kept in sync (maybe in realtime by repeating gfx operations done to RAM bitmap also in VRAM bimap connected to it. Or maybe only at specific times using things like damage list to keep track of what areas of VRAM bitmap are not yet in sync). Whenever a window bitmap needs to be composited to the screen the gfx system makes sure that real VRAM bitmap is attached so it can do the compositing hw accelerated. If system is low on free VRAM it can kill any other VRAM bitmaps connected to RAM bitmaps but it does not need to do the VRAM to RAM swapping as the RAM bitmap is always there and up to date.

Doing it like this causes some speed loss but I think this is how other OSes avoid described problems on systems with low VRAM.

Suppose I might as well dig out this oldie but goodie:

http://mrdoob.com/lab/javascript/effects/ie6/

Not that unrealistic emulation of Windows under heavy load.

[ Edited by stephen_robinson 21.08.2011 - 15:40 ]