You're the only other person I've come across running the 7260 on a VGN-Z (I own the Oceania equivalent of the Z690).
That aside, I'm currently trying to make use of the 7260 on my D54250 NUC (after giving up on the VGN-Z, and reverting back to the 5100 for that). For the 7260, even with the latest driver, I'm having some serious throughput issues. The speed variances are completely random, and for the life of me I cannot determine why. Near zero interference where I live, and the radio signal is going through one wall. As a comparison, my VGN-Z with the 5100 doesn't have a single hiccup.
Just tried the recommended settings and it's still a no-go. The 7260 is decent in some instances, and dismal at all other times.
If anything, I've pinged my wireless router multiple times and the ping times range from 1ms all the way up to 3000ms. So yeah, I'm still having issues.,,