Very low speed on QT, higher on NS?

Hello! I've just found out about soulseek and it's amazing! Been finding albums of some of my favourite bands with LPs in copies as limited as 50-200. Good job!

Anyway, to my question, first I tried SoulseekNS and it worked good and I got speeds ranging from 150-200 kb/s. After some reading I thought that it might be better to upgrade to the new version QT, so I've done that, but now I am getting a maximum of 40 kb/s, it usually starts at 80 or so then it just goes down to 40 within a minute and stays there.

I've already done manual port forwarding, ports 2234-2239 aswell as the one NS used (and the one after), for both TCP/UDP, then I added the same in my ESET Smart Security aswell as excluding it from protocol filtering and all that stuff, but the speed stays the same. I also tried changing from the 2235 to the NS one I got 26785 (forwarded both 26785 and 26786), says ports are open and everything should be working accordingly.

Is it supposed to be like that, is it just on certain downloads/users that the speed is slower and then faster on others? Or is it something with the client and my computer that doesn't go well together? Should I Just go back to NS?

Lots of questions now but thank you all.