g551 intel dual band N 7260 issues

hi all,

I'm having trouble finding a proper driver for my wifi card intel dual band N 7260...the drivers listed on the g551jk support have connectivity issues/no connection so i googled and found on a lenovo site newer drivers which have less issues but common speed drops (from 30mbit to 2mbit and ping from 13 to 773)

to sum up:

Asus G551JK
windows 7 64bit
intel dual band wireless N 7260

drivers i tried (all from windows 8.1 but are backward compatible):

Intel WiFi Wireless LAN Driver Version V17.0.6.1 (has problems/no connection)

Intel WiFi Wireless LAN Driver Version V17.0.1.5 (has problems/no connection)

Intel WiFi Wireless LAN Driver Version V17.13.2.2 (has less problems/speed drops)

any ideas?