download speed decreased

mcpain · Post by **mcpain** » Fri Jul 16, 2010 4:30 am

hi

i use 2 MB/Sec connection. my download speed was about 250 kbps before using tcp optomizer and i tweaked my tcp with tcp optimizer and my download speed decreased to 100 kbps

TCP Analyzer result after i used TCP optimizer

Code: Select all

« SpeedGuide.net TCP Analyzer Results » 
Tested on: 07.16.2010 04:09 
IP address: 59.94.xxx.xx 
Client OS: Windows XP 
 
TCP options string: 020405a00103030101010402 
MSS: 1440 
MTU: 1480 
TCP Window: 129600 (multiple of MSS) 
RWIN Scaling: 1 bits (2^1=2) 
Unscaled RWIN : 64800 
Recommended RWINs: 63360, 126720, 253440, 506880, 1013760 
BDP limit (200ms): 5184kbps (648KBytes/s)
BDP limit (500ms): 2074kbps (259KBytes/s) 
MTU Discovery: ON 
TTL: 49 
Timestamps: OFF 
SACKs: ON 
IP ToS: 00000000 (0)

pacificmall · Post by **pacificmall** » Fri Jul 16, 2010 4:41 am

Try the following with TCP Optimizer:

General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU - 1492
TTL - 64
Windows Scaling - check
TCP Receive Window - 127776 or 255552
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Timestamps - uncheck

Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 10
LocalPriority - 5
Host Priority - 6
DNSPriority - 7
NetbtPriority - 8
Lan Browsing speedup - optimized
QoS: NonBestEffortLimit - 0
ToS: DisableUserTOSSetting - 0
ToS: DefaultTOSValue - 80
MaxNegativeCacheTtl - 0
NetFailureCacheTime - 0
NegativeSOACache Time - 0
LAN Request Buffer Size - 32768

Rocky_Grim · Post by **Rocky_Grim** » Fri Jul 16, 2010 9:39 am

I think your TCP Recieve windows is to big for a 2mb line. Try Unchecking windows scaling and using a TCP Recieve Window of 63360.

Post by **Philip** » Fri Jul 16, 2010 9:46 am

Even with the bigger RWIN value it shouldn't half the speed unless there is severe packet loss or something else wrong with the line though... Test again. Increasing the TCP Receive buffer should have no negative effect on your throughput.

Rocky_Grim · Post by **Rocky_Grim** » Fri Jul 16, 2010 12:27 pm

I would start by checking your modem sync speeds. On a DSL connection you should be able to see what speed the modem is actually syncing at. Try typing 192.168.100.1 or 192.168.1.1 whichever it is to log into your paticular modem and checking the speed there. It should tell you your actual speeds in there some where.