2 EVGA 780TI reference models with Skyn3t's bios. Per the other posts on this thread, iv tried many combos of C/H/m with T at 15x24 with no luck
-C 2 -H 1 -m 1 -l T15x24 runs at 20khs no matter what C/H/m is at
Best auto was T480x1 at 620khs
This new version doesn't work so well for me

Try progressively lowering it from x24 down to 20 and maybe even lower, see if you get the best results with x20 as some of us do