drop in broadband speed

[#1]

please help.
my router used to sync at 8mb with me getting an actual throughout of 4-5mb.
the last couple of weeks my router has been sync at 4mb with my throughput at 2.7mb
tonight my router reports 1.4 and when i do a speed test it comes back at 1.2,
whats heppened to my speed?
below is the link to my speed test
http://www.speedtest.net/result/191701380.png
below is my router stats
Uptime: 0 days, 21:31:36              (i don't know why it says 0 days as it hasn't been switched of in a couple of weeks)

Modulation: G.992.1 Annex A

Bandwidth (Up/Down) [kbps/kbps]: 384 / 1.440

Data Transferred (Sent/Received) [GB/GB]: 1,61 / 2,26

Output Power (Up/Down) [dBm]: 12,0 / 13,5

Line Attenuation (Up/Down) [dB]: 5,5 / 14,0

SN Margin (Up/Down) [dB]: 6,0 / 21,5

Vendor ID (Local/Remote): TMMB / TSTC

Loss of Framing (Local/Remote): 0 / 0

Loss of Signal (Local/Remote): 14 / 0

Loss of Power (Local/Remote): 0 / 0

Loss of Link (Remote): 0

Error Seconds (Local/Remote): 301 / 0

FEC Errors (Up/Down): 56 / 0

[#2]

I have recently been complaining about my speed but,after building a new machine,I tried a speedtest on it.Shock was the only word for the 5.6 Mb result.I'm pretty sure its my wireless adaptor thats causing the problem although it says it has a good connection.I'll know when I get it changed but Plusnet are supplying the goods and my wireless network is the problem.

[#3]

ok, managed to get the router to sinc at 4mb but my speedtest still shows as just over 1.1mb
http://www.speedtest.net/result/191728767.png
Modulation: G.992.1 Annex A

Bandwidth (Up/Down) [kbps/kbps]: 448 / 4.416

Data Transferred (Sent/Received) [KB/KB]: 458,00 / 128,00

Output Power (Up/Down) [dBm]: 12,0 / 11,5

Line Attenuation (Up/Down) [dB]: 4,5 / 14,0

SN Margin (Up/Down) [dB]: 24,0 / 9,0

Vendor ID (Local/Remote): TMMB / TSTC
Loss of Framing (Local/Remote): 0 / 0

Loss of Signal (Local/Remote): 0 / 0

Loss of Power (Local/Remote): 0 / 0

Loss of Link (Remote): 0

Error Seconds (Local/Remote): 0 / 0

FEC Errors (Up/Down): 0 / 0

CRC Errors (Up/Down): 0 / 0

HEC Errors (Up/Down): 0 / 0

[#4]

Hi Greg,
Sorry to hear that you are having problems with your speeds.
Can I ask you to have a read of the speed link in my signature?  It explains how speeds on BTs ADSL platform work.
Because you were synchronising with the exchange at a poor speed and have since seen faster speeds, it's waiting for BTs profile to catch up.  This generally takes about 3 days.  If you maintain the sync speeds that you are currently getting then you'll see an incrementation in speed in 2-3 days time.

[#5]

hi james,
while im glad that my speeds went back up, its still not back to what it was a couple of months ago.

[#6]

Hi Greg,
I suspect that this is because you have an SNR of 9dB.  This probably means that BT detected some instability on your line and riased the "target SNR" on your line to counter this.  This rops you speeds slightly, but means that you won't disconnect, which in my book, is a lot better than having an increase in speed of maybe 500Kbps.