Got a new PC today and unfortunately noticed that I have exactly the same problem as MassMan now.
100% CPU usage on one core while scrolling, while marking text, or when there's a lot of activity in the active window.
Not having similar problems in any other applications than mIRC at all.
Intel Core 2 Duo E840 @ 3.00 GHz
ATI Radeon HD4870, 512 MB DDR5
2GB DDR2 RAM Dual Channel
Windows XP Professional SP3, 32 bit
mIRC v6.35
