Sounds like your LW needs more RAM. Go to preferences and disable the ultrapeer option under speed (pretty sure it's speed).

The download speed don't improve b/c you bought pro. The speeds are determined by numerous network factors, including but not limited to, your download speed, your soures upload speed, the number of sources, the stabality of your and your source's connections as well as the relative "distance" on the network.

If none of this works or helps, post your specs, and we'll get cracking.