The data transfer speed of the link is slow. The speed is controlled by the console. So far as I’m there is no way for the receiving software (WD) to influence the speed, so you need to expect long download times.
PS. Have you seen point 3) on the WMR200 data logging problems FAQ? You’ll see from that that there are other reasons to want to avoid hibernation/sleep when running WD beyond the problem you are having.