Hi chris and welcome.
2880 is quite a good sync speed for a 59.5 dB line.
>> Mainly at evenings although not really disconnecting but very slow at times,
Is your router recording a lot of CRC/HEC errors in the stats?
This is a common cause of slow speeds on long lines. To simplify things a CRC error is when data packets have been lost and have to be re-requested. It occurs when the dsl signal is weak and your router has to go "sorry didnt hear that.. can you send it again" - hence the slowness of data.
I dont see how capping the line will have affected this... by capping the line it just ensures that you dont in effect use the higher frequency bins which will be more prone to disconnects.
The only thing I can think of is that if you synced above say 3Mb and then your line dropped it would have re-negotiated a lower sync speed with sufficient margin to keep the line stable.
It could be that at 2880 once the evening comes, then your SNRM is dipping low enough to drop packets, but not low enough to cause a full disconnect.
You could perhaps try monitoring your routerstats during these periods to see if you SNRM has taken a bit of a dip and if the errors start increasing. If so, then you could try a physical reconnect yourself to see if this helps. - It could well be that the cap of 3000 is just a fraction too high.
Of course all the usual stuff also applies to ensure that you have done everything you can to get the highest SNRM value.
http://www.kitz.co.uk/adsl/lowSNR.htm
