kfc wroteI got a question: if i download AND upload at the same time, should i expect to get the maximal speeds for both up and down? or will one dramatically affect the other?
One will affect the other. The reason being even if you're only downloading you still need to upload ACK (acknowledgement) packets for the data packets you're downloading. If you're saturating your upload stream the ACK packets will get delayed, buffer space runs low, download speed drops slightly (or even data packets might get re-transmitted). Reverse the above when uploading, with the same end result.
I wouldn't describe the effect as dramatic, but it certainly can be noticed on a quality connection. The up and down streams will fluctuate below max throughput, rather than one of them running at max and the other being available for whatever non data traffic that needs to go through.