I had an issue on my ASUS P8Z77-V Z77 where I got low data speed and intemittent disconnections and my resolution was to download the Windows 8 Drivers (even if you are on Windows 7 they WILL work). (Make sure you get either the 32 bit or 64 bit versions as required) & extract them to the desktop, run the appropriate setup program and remove any existing Intel NIC drivers and software, reboot the PC and reinstall the drivers ONLY. Do not install Proset or anything below the driver checkbox. Uninstall anything else like TCP Optimzer AFTER you reset all registry changes back to Windows default.
By the way, this also solve the problem of not being able to uninstall the drivers. Do not use the ASUS or other manufacturers drivers, go to Intel support and search for 82579V. The ASUS drivers are out of date and they are broken anyway. The date for the 82579V driver that worked is 8/12/2012 (as shown in device mangler)http://downloadcenter.Intel.com/Detail_ ... 3&lang=eng
On Time Warner, I could not get any speeds above 2 meg before the change. After the new drivers, I am consistently getting speeds in excess of 25 meg. Go figure, at least this works. Do NOT reinstall TCP Optimizer, I tried with and without and simply reinstalling and running "Optimal" dropped my speeds back to 1-2 megs best. That program does nothing for Windows 7 only XP