Regardless of the conclusion I come to I'd be surprised if BT made any changes based on 1 forum thread, for me I'll just switch to another ISP such as sky or may be Zen. Plusnet and EE are owned by BT so I wouldn't be surprised if they end up with the same issue - assuming this is a BT problem such as an over subscribed network. Although if BT get a rep as bad for gaming I think they will lose customers.
BT do claim they don't do traffic shaping, so in theory this can't be a traffic shaping problem e.g. prioritising video and audio.
The tests I have lined up to do at the moment.
1. Tether my PC via WIfi to my mobile, run the same ping test with Tidal and see what my Overwatch ping is like.
2.Same test on a Win7 PC on the same network.
3.Run Tidal on a different PC and see if I can spot the same ping spikes on my Overwatch PC.
4. Load up the virgin connection at work, e.g. 4 x 4K videos and Tidal, check the effect on my Overwatch ping, do another direct comparison with my BT connection.
5. Start looking at data rates, Wireshark traces and other networking tools.
Last night I tried enabling the default 200ms TCP Acks, no real change observed, tried another NIC and went through all the NIC options e.g. offloading on / off, RSS and so on, went through all my router settings, tested many changes / options, rechecked my bandwidith (60Mb down and 19 up) - nothing made any real difference. Overwatch ping still 40+ms, still can't get this down to what it was a few weeks ago of below 30ms, stuttering game play with Tidal active.
There was smaller ping spikes when I reduced the Tidal quality to normal, so this is related to the amount of data being requested, but I'm not paying for Tidal to listen at normal quality.
Same test on Virgin, 4 x 4K videos playing and Tidal playing music, some minor ping spikes up to 30 odd ms and the odd packet loss, not perfect but nothing too shocking, I don't think I'd see any overly bad effects in Overwatch based on this. As mentioned this is work PC with many PC's using the same connection.
Same test on my BT connecton, same 4 x 4K videos playing and Tidal, the yellow spikes are around 200+ms, smaller green spikes around 50ms, even at 50ms that's about 2 to 3 times more than the average ping. The above varies to some extent based on I'd guess at what buffering is happening, so the screen shot is just a random capture, sometimes it's worse than this with more 200+ms spikes, other times not quite so bad with more 50ms spikes.
Either way forget gaming with this - it would be horrendous.
No problem me helping, I'm here because I've got the same problem, I want Tidal running the background while I game, I don't want my gaming messed up by just streaming music.
So testing on my other gaming PC which is a Windows 7 machine and not as powerful as my main rig I saw similar problems with ping spikes but interestingly they weren't as noticable as my main gaming PC. Overwatch was still flashing the network connection icon and stuttering here and there and Overwatch was still at 40ms instead of 30ms. I think here the PC just wasn't hitting the network so hard because the whole machine was struggling, I was only getting about 80 FPS at 1080p which is well below the monitor refresh rate of 144Hz.
So testing via my mobile phone was very messy, lots of packet loss, Overwatch ping at 90ms, there were ping spikes like via the BT connection but by moving my phone around seeing as I'm in a bad spot for 4G I did get to a point of no ping spikes. Overwatch was playable, I didn't spend long experimenting due to the packet loss but I got to the point of being resasonably convinced my mobile was able to serve up data without affecting the ping to the Overwatch game server when TIdal was running.
Below is the ping trace from my mobile connection while just playing Tidal, so no ping spikes but the red spikes showing packet loss / no ping response.
PC downstairs with netflix running, nothing running on my gaming PC - just the ping tracer, as below ping spikes around 50+ms, some around 75ms, I'm also now seeing some packet loss spikes at the 3rd hop happening. It's likely that Overwatch would soak these up with just a quick flash of the network icon - with no major stutter. Still at 50ms with the non-spiked ping at around 17ms it's a sizable spike.
I'd say even this is not great if your serious about gaming and have spent money to remove latency from your system.
As mentioned I'm on a fully wired network, with a high performance billion router - I'm seriously not happy with what I'm seeing 😐
You're lucky I've got to suffer this until Jan 2020 or pay a early cancellation fee of £228.
I can't even switch to Plusnet even though they're owned by BT.
I think the only option is to use netlimiter or something similar to restrict how much bandwidth Tidal or Netflix can use. I did try this and it helped to some extent, certainly didn't solve the problem. I restricted Tidal to 250KB/s which you'd think would not affect anyhing else when I've got 6MB/s bandwidth.