I was just wanting some advice. and I will start with my set up and go from there.
I renovated my house back in 2005, When I did this I completely ripped out all the phone wiring and installed cat 5 networking everywhere. All the Cat 5 goes back to a central point and where the switches and modem are. All CAt 5 wiring was run separately to electrical cabling including separate holes down the wall.  The phone line goes into the central hub cabinet. the modem connection is soldered onto the main phone line. The phone then goes through a Marqure Magnetis MM3200B splitter to a distribution board that has the Alarm disconnect and phone line patch cables. All patch cables are Cat5. The Phones and networking are all patched through the central hub, There are no dedicated internal phone lines
I noticed recently my modem connection speed was down to 2MBits. If I disconnect all the internal phone lines  from the distribution hub (leaving the filter attached to the incoming line) I get connection speeds of 5.1M
If I reconnect any thing to the Phone distribution hub (even a line to the phone without the phone) the connection speed drop dramatically 3-3.6M
My question is is this normal, Would the connection speed drop quickly like that even with just 2 phone lines connected or it something else going on (noise maybe) It does not seem to mater what cables are connected the result is the same
I have checked all the cabling out ans tried a million different combinations of patch leads and internal wiring always with the same result.