Model : TL-WPA4220KIIT

Hardware Version : V1

Firmware Version : 1.2.9 Build 160525 Rel.35241n

ISP : Virgin

I am getting bafflingly poor performance from my newly purchased TL-WPA4220 as follows:

* via powerline through both ethernet and wifi i get about 1.5 Mbps download and 5 Mbps upload
* with powerline unplugged via my router's wifi I get between 20 and 50 Mbps download and about 5 Mbps upload (which is not bad at all)
* through ethernet cable direct to router I get 70 Mbps download (which is what I am paying my ISP for)

This is very disappointing and a little baffling:

* the rate seems not to be limited by the ethernet rate (rates are 10 and 100 Mbps) at 10 Mbps
* if the rate was limited by the powerline I would (perhaps naively?) have expected the upload rate to be as poor as the download rate

Is anyone able to explain this? Better still can anyone tell me how to fix this?

Thanks in advance,

John