That could be proper for many web pages. I would not look to a new machine to speed that up much more than 2 seconds tops.

I like the PC you have as to RAM and keeping the hard disks from being 98% full. There is a VERY SIMPLE THING I'd like you to try. It's this -> Flip the IDE mode to PIO, say OK and then back to DMA. How to do this is noted at http://winhlp.com/node/10

Beyond that the other usual thing I do is scan it with MBAM.

To do much else you replace the machine.
Bob