A weird issue's arisen in our house. Around a fortnight ago, my brother started getting annoying lag spikes any time he was gaming online, regardless of the game (usually, it's Smite or FIFA 15). Everything else has been fine. After a few calls to BT - and a few line resets - we know the problem is on our end, but we don't have a definitive idea what could be causing it; we've effectively narrowed it down to either our powerline adapters (the most likely culprit at the moment), my PC, or the house's electrical wiring.
Both my brother and I use our PCs upstairs, connected wired through powerline adapters - these ones, to be precise, as well as a TRENDnet one that's feeding the internet from the BT Home Hub 4 downstairs and upstairs through the electrical wiring to us. When both of our PCs are on, he has problems playing online, but when mine's off, he has no problems whatsoever (tested it again earlier just turning off my powerline adapter and again, it was perfect for him). As far as I know, there's nothing on either PC that could be causing any problems - uTorrent and Steam usually hog the internet in the background on my PC, but the problems persisted even with them closed - and we haven't made any changes to our network recently; hell, we've been using those powerline adapters since June 2013, so it's weird that it's going wrong now.
The reason why I mention the house's electrical wiring as a potential culprit is because there has been a conservatory built in recent weeks - with electrical wiring out there, too - and the problems didn't begin until that was done.
Has anyone here experienced this before or know anything I can do here to try and pinpoint the problem? Because at the moment, I don't know what to do; solutions running through my mind are to either get new powerline adapters, get a long ethernet cable and run it upstairs, or get an engineer out to relocate the modem and Home Hub upstairs.