According to Shaws site your caps are 3000/384, if that is the case try the following settings in Cablenut:
DefaultReceiveWindow = 384000
DefaultSendWindow = 49152
DisableAddressSharing = 1
InitialLargeBufferCount = 100
InitialMediumBufferCount = 240
InitialSmallBufferCount = 320
LargeBufferSize = 81920
MaxFastTransmit = 64000
MediumBufferSize = 15040
PriorityBoost = 0
SmallBufferSize = 1280
TransmitWorker = 32
FastSendDatagramThreshold = 4096
EnableFastRouteLookup = 1
EnablePMTUDiscovery = 1
IgnorePushBitsOnReceive = 0
GlobalMaxTcpWindowSize = 64240 or 128480
MaxFreeTcbs = 8000
MaxHashTableSize = 16384
MaxNormLookupMemory = 5000000
SackOpts = 1
SynAttackProtect = 1
Tcp1323Opts = 0 (set to 1 if TcpReceiveWindow is 65535 or higher)
TcpLogLevel = 1
TcpMaxDupAcks = 2
TcpMaxHalfOpen = 100
TcpMaxHalfRetried = 80
TcpRecvSegmentSize = 1460
TcpSendSegmentSize = 1460
TcpTimedWaitDelay = 30
TcpUseRFC1122UrgentPointer = 0
TcpWindowSize = 64240 or 128480
MaxConnectionsPer1_0Server = 20
MaxConnectionsPerServer = 10
DefaultTTL = 64
DisableUserTOSSetting = 0
TcpMaxDataRetransmissions = 6
DefaultTOSValue = 92
Something I have read about Shaw Cable is that their internet speed is very unreliable, it fluctuates form person to person in the same area.... I don't know if it's true, just something I read.
P.S. Also set your NIC duplex mode to 100mb full duplex mode and try power cycling your modem.
