one of openoffice's known problem is its startup speed.
which browser u use? mozilla? u can try to use phoenix, which is much faster.
u can find some benchmark tools to test u linux speed. u cpu speed should be enought, memory is a little short for kde or gnome, a what type of disk u use? can u use iozone or bonnie to test u hd speed?
u can install a gkrellm to monitor u system activities.
many stuff on system measurement, tuning, and optimization, u can try to read some.