Broadband Pro Speeds...

[#1]

The BT BRAS profile shows 4000k as does the plusnet,
IP profile for your line is - 4000 kbps
DSL connection rate: 448 kbps(UP-STREAM)  4704 kbps(DOWN-STREAM)
Actual IP throughput achieved during the test was - 2728 kbps
Your High-speed Broadband Service
Your current broadband speed is 4000 Kbps
This is confirmed with the Plusnet Speedtest...
Date  Download Speed  Upload Speed 
Today 22:50 2445 kbps (306kB/s) 371 kbps (46.4kB/s)
Are there any network speed issues currently, thought Pro was supposed to be at line speed?
Cheers

[#2]

Have you optimised your MTU etc?
Assuming you are on a router, do you connect wired or wireless?
It could be exchange contention (Plusnet has no control over that)
Does the PN Platinum, Gold, Silver affect the BT speedtest? I thought it would bypass that. I would have thought results from something like http://www.mybroadbandspeed.co.uk/ would be more relevant.

[#3]

Thanks Jelv, of course... I've not been fault finding on broadband for a while. The BT speed test confirms that this is exchange side!
MTU default at 1400, will increase and post results. I'm on a router with wireless, tested wired and no difference.
Speedtest should circumvent traffic prioritisation

[#4]

Adjusted MTU from 1400 to 1500 and got an additional 500kbps on each test which is cool
If MTU is too high I'm guessing I will see some connection drops / packet errors increasing?

[#5]

I can't think of any way a higher MTU could affect connection drops. I suppose that with bigger packets it is possible that you might be more likely to see errors - but if it is it is probably more than outweighed by the reduced number of packets required to transmit the data.