I have HP motherboard with ATI Radeon HD 4650 1GB AGP and 1GB of RAM. This month I started to upgrade my PC. I wanted to disable Floppy drive. I went to BIOS and found that my AGP aperture size was 64 mb, that means that it's using my RAM, but Windows 7 with all applications uses about 60-65% of RAM. So to free RAM I changed the value to minimum (4 MB). After reboot my resolution was at 800x600 and ATI Catalyst said that something gone wrong with drivers or hardware. Also Aero went off.
So my question is: why this happens and what value I can use to enable Aero because even 64 MB is very important for me.