I do not think scripts/timers/etc. has anything to do with this problem, nor will it increase the likelihood of it happening. There's nothing to support that theory.
I do not think it has anything to do with video drivers or certain models of cards. It's been confirmed to happen on ATI and nVidia systems, using different driver versions, different OSes (Windows 7 vs. Windows XP), and different models of cards. That should come as no surprise because mIRC is a GDI+ application.
Honestly, from an engineer and programmer standpoint, this looks like some kind of repeated GDI window redraw/refresh that is being solicited by mIRC repeatedly when moving one's mouse cursor over a window which is not in focus and has multiple links (e.g.
http://blah/) in it. I can't get it to happen in a window that has focus.
I'd be able to confirm this idea if I had a way to monitor what WM_* messages were being sent or received by mIRC. My guess is that mIRC is calling
RedrawWindow() or
UpdateWindow() repeatedly when it doesn't need to. That would be due to WM_PAINT, which is usually sent from another application *to* something else, telling it that it needs to redraw/refresh. This is mIRC itself soliciting the refresh, not, say, another program telling mIRC "refresh the window".
Honestly I would have to bust out IDA Pro and try to reverse-engineer what is going on -- it's a hell of a lot easier to point Khaled to this thread and ask him to figure it out. He's the only one who knows the code.
As for CPU load -- no, my CPU load does not go "skyhigh" when this problem happens, but on an 8-core Intel i7-2600K I do see CPU usage that reaches 2%, and most of that appears to be kernel-level (which further proves something is stressing GDI). The load may also depend directly on the number of links which are visible at the time. But in your case, you see a 12% CPU spike when moving your mouse over links repeatedly; you're on a dual-core AMD system. 12% is *insane* for something as simple as moving the mouse over a link.
