With DLS it's usually 1/10 of download speed - but you really need to test it to be sure. In your case is that 256 kBytes/s or kBits/s?
Ex1: connection @ home 6MBit/s down / 600 kBit/up
Ex2: connection @ parents home 16 MBit/s down / 1 Mbit up
With already such a low download speed I wouldn't expect much.