It depends on a no. of things such as your available bandwidth for downlding. You won't get the maximum possible downld speed for a particular downld if you have too many downlding simultaneously b/c your downld bandwidth will be spread across each one & some will get more than others. At times the source(s) might only offer a small speed at that time so you might be able to afford to downld more without it affecting the others speeds. Knowing your downld capacity helps greatly here. eg: I am on a 256 kbps broadband plan & after overheads, I am able to downld using LW at 27 KB/s. So I know when I have reached or am nearing my maximum capacity.

Here's some speed tests (do them whilst LW is closed!):
1. http://www.adslguide.org.uk/tools/speedtest.asp

2. http://www.t1shopper.com/tools/speedtest/ (choose nearest location)

Here's some hints: See the following link & follow all the off-shoot links to find hints & extra skills to help downlding: To continue files downlding (click on link)