I have found new release drivers for Intel 7260 - 17.0.5
I'm used for Windows 8.1 64 from last 24 h and works good for me.
Intel® PROSet/Wireless Software and Drivers for IT Administrators
Intel® PROSet/Wireless Software for Windows 8.1*
Intel® PROSet/Wireless Software and Drivers for Windows 8*
Intel® PROSet/Wireless Software and Drivers for Windows 7*
I want to share an experience:
Yesterday I loaded the new drivers, installed it and had the same BAD result like with the drivers before.
Today I uninstalled the drivers as described here:
I had to repeat the uninstall of the driver round about 10 times. Every round a older version of the Intel driver as before was activated.
After the procedure I installed the version 17.0.5 of the driver and now I have a stable connection with an accetable speed, in the same enviroment, with HT enabled.
I don't know why it makes a difference? Intel, is your upgrade routine ok?