-do you have any of the assorted scripts etc that are supposed to speed up dcc? those cause probs such as you describe
-have you tried without any scripts on a clean copy of mIRC
-what OS do you have
-all size files or just large ones? you could have some limitations set at your isp
-keep in mind that the prob could be on the senders end. speed is only going to go as fast as the slowest end, which depends on several factors
-mIRC wasnt designed for major file sharing, its dcc capabilities are basic and aimed for occasional sharing between friends
