It all seems to work OK though. That will not help matters at all. Get up to 32 or 64MB at least, and you'll find much better performance. It works fine, though not as fast as a later model system. I never try to run X with less than 32M and preferably with 64M or more.
Memory is relatively cheap.
Get as much as the motherboard can handle. Check your manual. RAM is definitely one of the main issues you are running up against. I really don't use it too often for anything but simple browsing at the console as I have other machines behind it which are more for that purpose. Now I will say that your CPU isn't exactly helping matters too much, and you could very cheaply upgrade it as well, but your biggest issue is the amount of memory on your box.