16. The Optimizer does not tweak my MTU correctly ?

If you tweaked your Registry settings in the TCP Optimizer, however our online Analyzer still shows a lower MTU value, there is probably something on the line that limits your MTU. It could be software on your PC (such as AOL / Compuserve, PPPoE software), a broadband router, or your ISP.

The Analyzer actually looks at packets transferred between you and our server. Such packets are also limited by other routers on the path, while the Optimizer only tweaks your PC.

Here are some troubleshooting tips:
First, make sure that the Analyzer detects your external IP address correctly (not some proxy server).
Also, make sure your router is updated with the latest firmware, and check its Web-based management interface for a specific MTU setting you can adjust.
Note if you're on a PPPoE/PPPoA connection, the maximum packet size (MTU) can not exceed 1492.
You might want to try bypassing your router temporarily, to determine whether it is affecting your MTU value (by connecting your machine to the modem directly). Note you should reboot the modem every time you connect a different device to it.

Ultimately, if your ISP, or router are limiting your MTU, you can still simply tweak the rest of the settings using your particular MTU value. The exact MTU size has minor impact on throughput.