Lower MTU = Less Latency?

[Coder X]

When playing online games, i've read lowering your mtu gives you less lagg. Is this true...so if i set my mtu to 1 i'd get best results.

It's currently set at 1492(i changed from 1500), and i've noticed a difference. But people are still beating me and clicking at the right time.

What should it be? Any help would be awesome.

[trogers]

Try 1440. But when you change MTU, you also need to change TCP Window to remain optimum.

[Weedy]

Does this really work???

[Philip]

Smaller packets have a bit less latency... But headers become larger part of the whole packet, so throughput suffers a bit.

If you're aiming purely for gaming, you can try it. Here is a bit more information on packet size and latency: http://www.speedguide.net/read_articles.php?id=111

Keep in mind that many games use UDP traffic (that uses different packet sizes), MTU is for TCP traffic, so your mileage may vary.

[Weedy]

what would be a good RWIN to set my computer to if I changed my MTU to 1440?
I live in calgary, AB, CA and am paying for a 5mbps down connection

« SpeedGuide.net TCP Analyzer Results »
Tested on: 09.15.2008 23:56
IP address: 68.144.xx.xxx

TCP options string: 020405b40103030101010402
MSS: 1460
MTU: 1500
TCP Window: 128480 (multiple of MSS)
RWIN Scaling: 1
Unscaled RWIN : 64240
Recommended RWINs: 64240, 128480, 256960, 513920, 1027840
BDP limit (200ms): 5139kbps (642KBytes/s)
BDP limit (500ms): 2056kbps (257KBytes/s)
MTU Discovery: ON
TTL: 50
Timestamps: OFF
SACKs: ON
IP ToS: 00000000 (0)

[trogers]

what would be a good RWIN to set my computer to if I changed my MTU to 1440?
I live in calgary, AB, CA and am paying for a 5mbps down connection

(MTU - 40) x highest even number to get a value just below 65535 and then multiply it by 2.

1400 x 46 = 64400 x 2 = 128800

[Weedy]

thanks for all the help guys
one last question if you don't mind: If I edit MTU on my computer would I have to change it on my router as well? I'm connected via LAN

[trogers]

Just change the settings in your comp.

Try the following with TCP Optimizer:

General Settings tab:
Custom settings - check
Modify All Network Adapters - check
network adapter selection - your NIC
MTU - 1440
TTL - 64
TCP Receive Window - 128800
MTU Discovery - Yes
Black Hole Detect - No
Selective Acks - Yes
Max Duplicate ACKs - 2
TCP 1323 Options:
Windows Scaling - checked
Timestamps - uncheck

Advanced Settings tab:
Max Connections per Server - 10
Max Connections per 1.0 Server - 20
LocalPriority - 1
Host Priority - 1
DNSPriority - 1
NetbtPriority - 1
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