@andreu1 wrote:
using hardwired pc.
Should that make a difference?
All computers generate a certain amount of radio interference which can affect the available bandwidth which VDSL can use.
This is will show as a reduction in the noise margin, and maximum data rate, in your case, its not significant. In some cases it can cause the connection to drop if the interference is bad.
If you are downloading, then the computer will be working harder and is likely to generate more interference.
Often its simply the internal switched mode power supply which generates more electrical noise.
You may be able to reduce this by ensuring that the computer is sited away from the home hub, or any phone wiring.
Some interference can be carried over the mains wiring, so a filtered socket on the computer may help.
Computer power supplies do have some mains filtering, but its not really that effective at VDSL frequencies.
I used to have an LED lighting power supply unit which caused my ADSL connection to drop, due to its plastic case and poor filtering. Its now been replaced 
Sorry if all this sounds a bit technical, but I spent many years on interference investigation.
