My typical speeds are as follows;
D: 21mb/s
U: 0.5mb/s

But recently they have dropped to 2 & 0.3mb/s respectively.



Here are my stats from MLab

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Your system: Windows 7 version 6.1
Java version: 1.6.0_20 (x86)

TCP receive window: 1240832 current, 1575424 maximum
6.98812E-4 packets lost during test
Round trip time: 120 msec (minimum), 575 msec (maximum), 305.31 msec (average)
Jitter: 455 msec
0 seconds spend waiting following a timeout
TCP time-out counter: 608
108 selective acknowledgement packets received

No duplex mismatch condition was detected.
The test did not detect a cable fault.
Network congestion may be limiting the connection.
No network addess translation appliance was detected.

0.9388% of the time was not spent in a receiver limited or sender limited state.
84.46000000000001% of the time the connection is limited by the client machine's receive buffer.
Optimal receive buffer: 1613234176 bytes
Bottleneck link: Cable/DSL modem
0 duplicate ACKs set

--------------------------------------------------------------------------

WEB100 Kernel Variables:
Client: localhost/127.0.0.1
CurMSS: 1382
X_Rcvbuf: 87380
X_Sndbuf: 258912
AckPktsIn: 673
AckPktsOut: 0
BytesRetrans: 4146
CongAvoid: 360
CongestionOverCount: 0
CongestionSignals: 1
CountRTT: 501
CurCwnd: 77392
CurRTO: 608
CurRwinRcvd: 1240832
CurRwinSent: 5888
CurSsthresh: 67718
DSACKDups: 0
DataBytesIn: 0
DataBytesOut: 2003026
DataPktsIn: 0
DataPktsOut: 1431
upAcksIn: 169
ECNEnabled: 0
FastRetran: 1
MaxCwnd: 136818
MaxMSS: 1382
MaxRTO: 811
MaxRTT: 575
MaxRwinRcvd: 1575424
MaxRwinSent: 5888
MaxSsthresh: 67718
MinMSS: 1382
MinRTO: 479
MinRTT: 120
MinRwinRcvd: 66304
MinRwinSent: 5840
NagleEnabled: 1
OtherReductions: 1
PktsIn: 673
PktsOut: 1431
PktsRetrans: 3
RcvWinScale: 7
SACKEnabled: 3
SACKsRcvd: 108
SendStall: 0
SlowStart: 139
SampleRTT: 428
SmoothedRTT: 358
SndWinScale: 8
SndLimTimeRwin: 66002
SndLimTimeCwnd: 9569598
SndLimTimeSender: 558358
SndLimTransRwin: 1
SndLimTransCwnd: 13
SndLimTransSender: 12
SndLimBytesRwin: 2804
SndLimBytesCwnd: 1959996
SndLimBytesSender: 40226
SubsequentTimeouts: 0
SumRTT: 152960
Timeouts: 0
TimestampsEnabled: 0
WinScaleRcvd: 8
WinScaleSent: 7
DupAcksOut: 0
StartTimeUsec: 878458
Duration: 10195052
c2sData: 2
c2sAck: 2
s2cData: 8
s2cAck: 3
half_duplex: 0
link: 0
congestion: 1
bad_cable: 0
mismatch: 0
spd: 1.57
bw: 1.31
loss: 0.000698812
avgrtt: 305.31
waitsec: 0.00
timesec: 10.00
order: 0.2511
rwintime: 0.0065
sendtime: 0.0548
cwndtime: 0.9388
rwin: 12.0195
swin: 1.9753
cwin: 1.0438
rttsec: 0.305309
Sndbuf: 258912
aspd: 0.00000
CWND-Limited: 51.92
minCWNDpeak: 11056
maxCWNDpeak: 136818
CWNDpeaks: 1

The theoretical network limit is 1.31 Mbps
The NDT server has a 126.0 KByte buffer which limits the throughput to 6.46 Mbps
Your PC/Workstation has a 1538.0 KByte buffer which limits the throughput to 39.36 Mbps
The network based flow control limits the throughput to 3.41 Mbps


Client Data reports link is 'T1', Client Acks report link is 'T1'
Server Data reports link is 'OC-48', Server Acks report link is 'Ethernet'
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This has been driving me nuts. Please help!