Minimum ram for kubuntu?

[joe at actionline.com]

What is the minimum ram required for kubuntu?

Some online sources say it should run okay with 512-meg of ram.

I'm trying to set up an old Dell for a friend and since I can't seem to
get win-xp wireless to work, thought I'd try kubuntu.  The unit has only
512-meg of ram and when I tried a live kubuntu CD, it worked okay, albeit
slow. So I installed it on half the HD as a dual-boot and it runs, but
very slow and it hangs up.  Is there some way to salvage this old box?