Hi Chris
The patch has no way to effect your downloading speeds, so we need to look at other things that could be causing this for you. Its a coincedence, typical of computers..
Can you give us a bit more information about your operating system, firewalls, antivirus, and whether you use a router or dsl modem?
Also what version of WinMx are you on and what did you do when you installed the new patch. Like did you get an updated version of Mx at that time?
Are you on primary or secondary on MX?
Thanks