Are you refering to using more than one p2p share programs at one time. Then yes both will want to get the most out of the bandwith that they can.

As far as your colour goes, that could be related to your graphics card. See The way to fix the Blank screen on startup which might also apply to you but in a lesser way. The answer might be the same. (I believe the new beta overcomes this issue & also the one about your computer resources.)

Also see this: To continue files downlding (click on link) & the off-shoot links as there's some tips & skills you may find valuable. Some may help to fix your comp resources & bandwidth problem.