Soldato
Its usually pretty quick but yeah something cant be right a lately i thought it might have been the PSN servers. Ive just looked on the router settings and cant find anything to do with power levels really, i've got the wireless speeds up to 144mb on both 2ghz and 5ghz which is best for wireless range, as the 144mb max speed is more than adequate.
Are you with virgin media, you can find power levels in the superhub router Webpage in the top right (no need to log in). Might not be that though if you get good speeds on all your other devices.