|Vista and Seven both cache your frequently used programs in memory, but 50% does sound quite high. My main system also has 4GB of RAM, but W7 Ultimate x64 only needs 15% of it at the desktop. |
Review your msconfig. If you have an HP printer or scanner, uninstall or disable as much HP bloatware as you can. HP writes some amazingly crappy software.
Most Cyberlink, Adobe, HP, update/regiseration service for any software, and Creative (except the main driver) can be disabled.
HTPC | Pentium M @ 2.82GHz, 2MB L2) | 4GB | 1.0TB | Radeon HD5750
Blu-Ray | Win 7 Pro | HDMI out to Onkyo TX-SR707 AV receiver