ive been useing limewire for several months now and recently have noticed when i leave the puter to let downloads run on there own. when i leave my downloads are running turbocharged when i return my connection is excellent. then it has to wake up connection. is this something that can be fixed or is it running the way it is supposed to?

running xp pro
celeron 600
i keep around 3 to 5 gigs available most of the time
isp advertised at 384/192 altho after getting cut off one time my isp changed my addy and recent speed test showed 1075/452 (think they made a mistake)

also another question. given my decent upload speed how many slots should i keep open.
i share audio and dvd length video files with the majority of the hit being the video files.