I strongly suspect your isp Imag!ne use traffic shaping technology to purposely cause problems with programs like winmx
(your ip resolves to filter5.filter.imagine.ie)
in these circumstances you're fortunate if winmx actually works propoerly at all, never mind quickly, funnily enough i was only talking to someone yesterday who found a page where traffic shaping was listed as a feature of their service, but i can't seem to locate the page concerned today....
there's little if anything besides changing isp you can do about it if this is the case.