My laptop has 256mb of shared graphics memory. Whats the difference between this and normal graphics memory?

I have a game which requires a graphics card with at least 128mb memory, but this doesn't work on my laptop.

The reason for the perforamce difference is that system RAM is of a lower quality than RAM on a dedicated graphics card. Plus, there is more contention due to the memory bus being used by other parts of the system. The graphics card gets around all of these issues by having a dedicated CPU and chipset.

Laptop graphics cards in general are less powerful than their desktop equivalent because they have to be so small and consume much less power and give off less heat. So even a dedicated laptop graphics card may have difficulty with games.

Hope this helps!

But 256mb of it should surely make up for the fact that its of less power?

Not for a laptop - because shared memory means that the memory its using is the system ram. So its of less power & its being shared with the system. Plus, there's no dedicated graphics processor, further reducing performance.

Of course, if your laptop does have a dedicated card then it may be possible to upgrade it.

But from what you have said - having 'shared memory' graphics, then this wont be the case.