by old_death » 01 Sep 2012 19:17
Shareaza allows you to download only at the speeds other people will upload to you. As upload bandwidths are generally slower than download bandwidths, it may well be that in your case, 300 KB/s is all you'll get. However you might be able to improve your download by improving your upload speed, as the more your upload, the more credits you collect on those clients you upload to, who in turn will grant you more from their upload bandwidth.
As for your question about loosing your partials on reinstall, I can assure you that they should be just fine after doing so.
On a side note: Did you notice we released a new Shareaza version not long ago?