Ensure that you have the latest drivers for your modem, from the manufacturer & not Microsoft.

Here are some tweaks that will help you maximize throughput as best possible, for your 56K modem.
Please create a System Restore point before tweaking

Download Cablenut & use the following settings:

DefaultReceiveWindow = 8192
DefaultSendWindow = 4096
DisableAddressSharing = 1
InitialLargeBufferCount = 10
InitialMediumBufferCount = 24
InitialSmallBufferCount = 32
LargeBufferSize = 4096
MaxFastTransmit = 6400
MediumBufferSize = 1504
PriorityBoost = 0
SmallBufferSize = 128
TransmitWorker = 32
FastSendDatagramThreshold = 1024
EnableFastRouteLookup = 1
EnablePMTUDiscovery = 1
IgnorePushBitOnReceives = 0
GlobalMaxTcpWindowSize = 8760
MaxFreeTcbs = 2000
MaxHashTableSize = 4096
MaxNormLookupMemory = 5000000
SackOpts = 1
SynAttackProtect = 1
Tcp1323Opts = 0
TcpLogLevel = 1
MaxDupAcks = 2
TcpMaxHalfOpen = 100
TcpMaxHalfOpenRetried = 80
TcpRecvSegmentSize = 1460
TcpSendSegmentSize = 1460
TcpTimedWaitDelay = 30
TcpUseRFC1122UrgentPointer = 0
TcpWindowSize = 8760
MaxConnectionsPer1_0Server = 8
MaxConnectionsPerServer = 4
DefaultTTL = 128
DisableUserTOSSetting = 0
TcpMaxDataRetransmissions = 6
DefaultTOSValue = 92

Open your registry (start -> run -> type regedit) and change the following registry entry:

Export each registry setting before amending

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\AFD\Parameters
Add the parameter BufferMultiplier and give it a value of 400 hexidecimal which will make it 1024.

Download TCPOptimizer and use the following settings:

Under the settings tab select dial up and custom settings, in network adapter selection choose dial up adapter. Then use the following settings:

MaxMTU - 1500
TCP Receive Window - 8760
MTU Discovery - Yes
Black Hole Detect - No
Selective ACKs - Yes
Max Dup ACKs - 2
Time to Live (TTL) - 128
TCP 1323 Options - uncheck both boxes

Other settings:
Max Connections per Server - 4
Max Connections per 1.0 Server - 8

Then select Apply changes and reboot your computer.

Go to Network Connections from the Control Panel – right click on your internet connection and select properties, uninstall QoS Packet Scheduler.

Amend the following registry entries:

delete the following entry
HKEY_LOCAL_MACHINE/Software/Microsoft/Windows/CurrentVersion/Explorer/RemoteComputer/NameSpace/{D6277990-4C6A-11CF-8D87-00AA0060F5BF}

add the following entry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Contro l\PriorityControl (if PriorityControl is not there, make the value) - on the right hand side right click and select new DWORD value, name it IrqXPriority (X = Irq assigned to your modem), then right click it and select modify and give
it a decimal value of 1.

This tweak will help web pages load faster, it has no real effect on download speeds, just helps your pc look up websites faster thereby speeding up
how fast the page loads and making websurfing more enjoyable.

Go to the registry entry and change the following settings:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Servic es\Tcpip\ServiceProvider

Class - 1
DnsPriority - 1
HostsPriority - 1
LocalPriority - 1
NetbtPriority - 1