This is probably graphics driver stuff. Are you using an Intel 965 GMA graphics chipset?
That chipset gets cursor lag whenever there's a CPU spike (like when rendering JS-intensive web pages such as Facebook). I believe it's been that way since KMS was implemented, and as far as I know there is no solution. You could try this workaround:viewtopic.php?f=24&t=2856
which in my experience works for *some* Intel chipsets on *some* kernels.
OTOH, if it's an old Radeon chipset, you might be able to just turn off KMS. I have a Pentium 4 laptop whose Radeon chipset lags like mad with KMS, and is faster on Linux than on Windows without... No idea why.
(But sadly you cannot turn off KMS on Intel chipsets. I know it's the Light, the Way, and the Future, but it still has some pretty big performance issues IMO - even on the latest version of Ubuntu, let alone Salix 13.37.)