I used to have WinMX for a while and i just started using LimeWire which seems pretty slow when it comes to downloading, the downloads start out slow and sometimes the speed goes down to 0kb, when i'm on WinMX i get much faster downloads, is there something i'm doing wrong, should i adjust something in options?

I don't know if this matters or not but i have a Cable High Speed 3MB Connection.

There are some vendors, namely Shareaza, that allow far too many simultaneous uploads, so the speed get's very low.

You also might want to check if your router/firewalled is configured to accept incoming tcp connections and udp packets on your Gnutella port. Gnutella will always be slower and return less results for firewalled users.