A problem reported in a german forum:
Teensy 3.2 + Arduino1.6.5 (Win) + Teensyduino 1.25 + FastLED3.1
WS2812 Leds (http://www.flikto.de/products/sparkfun-led-rgb-addressable-pth-5mm-clear-5-pack)
The lib examples seem to work fine only with 24MHz CPU-Speed. At 48MHZ many distorted frames, at 96MHz no frames at all.
Additional Info: With the Adafruit lib results also only with CPU speed <96MHz.