SG TCP Optimizer
TCP Optimizer 4 (latest stable release that works with Windows XP, 7, 8, 8.1, 10, 2012 Server, etc.)
The program can aid both the novice and the advanced user in tweaking related TCP/IP parameters in Windows, making it easy to tune your system to the type of Internet connection used. The tool uses advanced algorithms, and the bandwidth*delay product to find the best TCP Window for your specific connection speed. It provides for easy tuning of all related TCP/IP parameters, such as MTU, RWIN, and even advanced ones like QoS and ToS/Diffserv prioritization. The program works with all current versions of Windows, and includes additional tools, such as testing average latency over multiple hosts, and finding the largest possible packet size (MTU).
The TCP Optimizer is targeted towards broadband internet connections, however it can be helpful with tuning any internet connection type, from dialup to Gigabit+ :) It is completely free, requires no installation, and has been downloaded over 8 Million times.
If you need help with the program, check the TCP Optimizer documentation, read our broadband tweaking articles, the Optimizer FAQ, and/or visit our Forums. The program can be freely (re)distributed, as long as you give us proper credit as the author, and it is not sold for profit.
Mirrors:
SpeedGuide.net (newest version, recommended)
MajorGeeks.com
Download.com
Softpedia.com
CHIP Online (German) version 4, (version 3)
GIGA Software (German)
OS: 
Windows 9x/ME/2K/XP/XP-SP2/2k3/Vista/7/2008/8/8.1/10/2012 Server
| version: 4.06
| date: 2016/09/07
| file size: 680 KB
Legacy Versions:
TCP Optimizer v. 3.08 (deprecated, supports versions up to Windows 7/2008 Server, does not support Windows 8/10/2012)
TCP Optimizer v. 2.03 (deprecated, unsupported, released 01/06/2006, supports versions up to Windows XP)
TCP Optimizer v. 1.00 (deprecated, unsupported)
www.RMSComputer.com
TCP Optimizer