I am indeed on a kernel and some X11 components from jessie-backports in any case for better iGPU support on Broadwell.
Using the latest Intel provided firmware for the kernel driver version (v13) has resulted in increasing the time-to-failure. It now fails in hours instead of minutes. Power cycling the radio does not make a full recovery anymore with the latest compatible firmware.
Before failure:
100 packets transmitted, 100 received, 0% packet loss, time 99115ms
rtt min/avg/max/mdev = 10.770/21.391/131.100/17.115 ms
After failure and radio power cycle:
100 packets transmitted, 94 received, 6% packet loss, time 107310ms
rtt min/avg/max/mdev = 12.219/6037.145/19665.521/4837.827 ms, pipe 13
Performance returns to normal after a full reboot cycle.
-- Joni Orponen