If you put it in the drive bay (normal mode), it's basically good for monitoring (CPU temp, CPU fan rpm, bclk and ratio). If you install 'ROG connect plus', the OC button does function. The fan profile button does nothing and I came to the conclusion it's only for the OC panel fan headers (although I have ASUS documentation that says otherwise).
As for the OC button, it worked, but not really as expected. It functions more as a UC (under clock) button. The button transitions from 'normal' mode, to lv1, to lv2 and back to normal again. 'normal' is whatever you have OC'd to. lv1 and lv2 come from the ASUS 4.0, 4.2 and 4.4 pre-selected (you'll see them reference in the BIOS and AISuite 3). I played with it a little and here is what I learned. I had the R5E booting stable at 4.5. This will be the 'normal' mode on the OC panel. 45 is shown as the ratio when I boot the PC. If I hit the OC button, Lv1 shows up on the panel and the ratio changes to 40. If I hit the button again, it's Lv2 and 42. One more time and it's back to 45.
I compared benchmarks between 40 and 45 (I was playing).
The on/off button also works. Did it come in handy? Sometimes. Does it look good? If you have an open drive bay.
If you spend more time than I, you might find out more about it. Remember to install 'ROG Connect Plus' if you think the OC button (and maybe the fan if I missed something) might be useful to you.
Edited by BarneyRubble - 9/21/15 at 9:14am