@Space_frog
The line sync speed isnt a reliable indication of the real speed you will get, but yes at 290 one would expect it to be faster than 80mbps.
I recommend you keep testing this every few hours and during peak / non peak times to see if this changes. If you can see it increasing hour by hour as you leave peak time it may well be throttling that causing it. Ideally rule this out first as its a common thing for ISPs to do during peak times to increase capacity, easy to spot as you will see the speed increase almost per hour, then down again at next peak.
Look for this type of thing
6pm 80mbps
7pm 80mbps
8pm 90mbps
9pm 100mbps
10pm 120mbps
11pm 150mbps
12 midnight 200mbps
etc etc
If you are syunced at 290 then you must have the right settings, otherwise it simply wouldnt connect at that speed.