You probably should try new linux kernel. There is
high chances that it will
fix these problems for you. Personally I use 2.6.23-rc8. You find that with
new kernel performance is very good even under heavy load....
...But when I have purchased 3 GHz quad-core system with 8 GiB of RAM I (again!)
found big problems with fairness of CPU sharing... Instead of trying to fix this myself I decided to try
experimental 2.6.23-rc3 Linux kernel with new scheduler.
And now, finally, I have good performance even under heavy load on my system
with standard Linux kernel! I can copy big files, run multi-threaded
scientific calculations in background (with total average load of about 6-12
or more) and play 3D-games in WINE simultaneously on my quad-core system....
I didn't tested yet my one-core system with new 2.6.23 kernel so I'm not sure
how well it will behave with uniprocessor system but I guess it should work
as expected.
Please test with your uniprocessor and get back to us on it. Not all of
us can have the top-of-the-line system.