I opened up the console and noticed a constantly repeated error every few seconds:

Safari [231] <Error> unknown error code: invalid drawable

I have noticed no problems with Safari.

I've also noticed this one pops up regularly:

***Assertion failure in - [NStextFieldCell_objectValue:forString:errorDescrip tion:], /SourceCache/AppKit/AppKit-1038.35/AppKit.subproj/NSCell.m1531

I have no idea what either of these mean, can anyone help?