You do not need to have all the lights lit, as long as they are green and not red. Have you tried a comparitive speed test? You could try putting the adapter on a short USB extension to bring it out from the PC. It is surprising how much difference moving it a couple of feet can make.

If you have not already done it, click the DrTCP link below and run the Tweak Test. If advised download and run DrTCP to make the changes. Do a 'before and after' for comparison.