Hi everyone. I've been using IRC for quite a while, and just recently (the few past weeks or so), my client has been lagging greatly. I'm not talking about the connection, but the client. If I start typing something, it will begin to show but then suddenly freeze. Anywhere from 5-10 seconds later, the text will finally display. Also, sometimes my channel windows won't switch, and I'll have to click on them a few times until it actually shows up. In addition, mIRC stops responding entirely (the window will fade white for a few seconds) at random times. This has never happened to me before, so what's happening? o_o Thanks.

When this happens to me, it's usually due to the fact that I have something working in background that is using a lot of system resources, like my anti-virus auto-scan.
The other main cause, is when my hard drive needs to be defragmented.

In either case, it is not a mIRC problem, just noticed in mIRC due to the constant interactivity of the program.

The only thing in mirc that take so much time to run and that show a white mirc main window is a loop, nothing else should cause this.
To the OP, try with a clean install of mirc 6.35 and see if you can confirm this slowness

I don't run a firewall or anti-virus (no need to), so I'll try a clean installation. Thanks, I'll get back to you on this.

Please note that running without a firewall or anti-virus protection is very dangerous.
I can not recommend that you maintain running your system in this manner, but I also can not force you to change your mind.

The security concerns regarding using/not using firewall/anti-virus programs have been stated so many times, I'm not going to get into them.

I've been experiencing the same problem. mIRC worked fine on my old PC on XP, but now that I switched to Vista 64bit, this started happening. Is it possible its due to many networks and channels being open? On 59 channels over 11 networks at the moment and I noticed when I start up mIRC that at first its fast, then after I join ~15th channel or so it starts lagging. It's really annoying and I've no idea really what the problem could be (yes, I tried turning off firewall, closing background processes, fresh install etc.).

Not only is it possible for the multiple channels/networks issue to be the cause, it is, in fact, probable.

While mIRC can connect to many networks and many channels, the more networks and the more channels it has to reference, the slower it's going to be, since mIRC is a single threaded application.

The detected slow down while using multiple channels/networks has been mentioned before many times.

Yeah I figured it might be that, however I find it extremely unusual since I was on the same amount of networks/channels on my old PC that only had 1GB ram, some old P4 processor and was running XP SP2 and everything was fine there. This pc has Q6600 quad, 4GB of ram and Vista 64bit so it's definitely not lack of resources as I have plenty.

You're still hitting the processing limitation of mIRC, as it is a single threaded application.

There have been suggestions and comments, both pro and con, to making mIRC a multi-threaded application.

As stated, you're noticing the difference more readily since your system does have the extra resources in comparison to your old system.