HD Quality will use around 5 of that, any other devices like phones or tablets could be an issue too. Therefore its not too unexpected for this to cause issues.

Don't really not what else to suggest mate

Just upgrade your current broadband then? Sucks you cant get fibre though lol, but just phone your broadband and ask them for an upgrade, it will cost you more but worth the money.

Mikey wrote Just upgrade your current broadband then? Sucks you cant get fibre though lol, but just phone your broadband and ask them for an upgrade, it will cost you more but worth the money.

I don't think he can go any faster broadband wise without actually upgrading to fibre. The Max broadband speed in the UK is up to 17mbps due to it running from the old copper cables (which causes hard throttling as everyone in street is basically sharing the speeds).

OP: Only thing i'd say you could do to fix this is either use 4G (Which will be costly) or apply/wait for a company to install fibre in your street. I was in the exact same situation for around 6 months averaging around 4mbps download it really isn't internet in my opinion and i still don't have great speeds even till this day. The UK in general is terrible for internet the sooner they actually do something about it the better.

15mbps is what you roughly pay for but it's not exactly what you get. Can we get a screenshot of your speed test?

Netflix or any streaming service is a huge bandwidth hog which is probably why you're lagging on your Xbox. The more bandwidth towards your router, the more latency on your Xbox and, most of your devices in your house will have trouble finding available traffic to your internet. Even your phone or just an AFK computer is still using bandwidth and fighting with all the other devices so try turning all unused items that are hooked up to your router off.

Personally, I have 5mbps at my first house and I can only run my computer / Xbox while watching Netflix. I have to turn my phone off and any other device that is trafficking to my router. If not, my latency will be incredibly high and unplayable or my Netflix will just keep buffering every 10 minutes.

when someone is watching something on the internet via console or youtube or even live videos your speed gets cut in half to commendation to both the hd watcher who is also needs a little more speed to run, since xbox live uses quite a bit of bandwidth ontop of that playing hd videos or watching like i said live videos will cut the speed even more when youre playing on xbl which the service and the game servers also need bandwidth, when i had 1mb up and down my games would tend to lag like crap when someone else was playing online or watching youtube, but if you get 15mb you should at least have enough bandwidth left for online play, i would speed test and see the speeds you get if its not what youre paying call your isp, im not that good with how much live uses but i know its quite fair bit needed to load the ads and the games servers are what eats most of the bandwidth