nxPascal

[LP]

As you probably know AERO desktop on Windows Vista and newer save contents of each whole window (window texture) from every non minimized program which is running. And theese are stored in Graphic Memory. This means that more programs you are running higher is GPU memory consumption.

Since you are talking about AERO, please check WDDM, which allows video memory paging. What this means is that technically the video memory is not bound by the limitations you explained. In other words, you may stop worrying that you'll end up without video memory on Vista+.

As for flickering this is only present becouse Windows needs to move some data (window textures) from normal meory back to Graphic Memory so that it can be used for rendering other applications windows.
And on Windows XP or older there can be a bit more flickering since all windows needs to be redrawn compleetly and we all know how slow canvas redraws are.

Flickering is caused by rendering being out of sync with vertical retrace, therefore enabling VSync resolves the issues in most cases. Please do not confuse or mix Windows XP and Windows Vista+, as the two use very different approaches and completely different driver models.

(GUI from Windows XP and older is canvas dependant while Windows Vista and newer using Aero desktop means that whole GUI is DirectX overlay surface based which alows much faster redraws).

Not according to the following:

In Windows Vista, all Windows applications including GDI and GDI+ applications run in the new compositing engine, Desktop Window Manager which is built atop the Windows Display Driver Model. The GDI render path is redirected through DWM, and GDI is no longer hardware-accelerated by the video card driver. [4][5] However, due to the nature of desktop composition (internal management of moving bitmaps and transparency and anti-aliasing of GDI+ being handled at the DWM core), operations like window moves can be faster or more responsive because underlying content does not need to be re-rendered by the application.

Actually, it's Windows 7 that brings back hardware acceleration to GDI, but on Windows Vista it's made entirely in software. [Reference]