KDE 4 firefox memory leak

Im running KDE 4.1.2 and firefox 3.0.3
Im using the asus 701 with 512meg ram and it has 900mhz processor
Now it all seemed fine till i had a few tabs open in firefox it would grind and start disk reading like memory leak…
I tried konqueror but that is just crashing which is a pain
Anyway i have done ctl+esc and right clicked on firefox and reniced the application i notched it down a tad it seems to be fine…
Could be a indication that i may need to upgrade my 512 ram to 1 gig ram?

If this carries on ive read on forums to try turning of desktop effects…
Which is a pain as im using the mosiac feature in kde4 which comes with the desktop effects enabled only :-(