Well, i have the same video integrated system, only that it is on a laptop, so I cannot change it.
But in the graphics controller program I found that the card uses from 8 to 64 Mb of memory and it also shows what amount it uses when I check. So i spent some time trying to get higher than 20 Mb values for this (games) and it just cannot seem to be able to go higher, and the games i am playing don't go smooth.
For example I can only play Nfs underground 2 in 800x600 and low graphic settings, and my card uses 22 Mb of the Ram from its 256Mb, and with a P4 2,3Ghz.
I don't know if it is normal or not so that's why i am asking u guys

, maybe some kind of tweak utility which forces the video card to be fully operational, but I couldn't find it yet.
Thanks in advance, hope to hear from u soon.