If you are mining on Windows 64-bit version best free skunk miner is tpruvot's ccminer 2.2, 32-bit, x86 version.
It is about 5% faster than x64 – that's deference of about 3MH/s, just by running/compiling x86!

Also more hashes can be achieved fine-tuning miner intensity to decimal numbers, until you reach best results for your setup.
Try it, go by really really small decimal steps for intensity, it can make some pretty BIG differences.

I found out that for me intensity of 21.0956 makes difference of about 1-2MH/s more per every single 1080 Ti compared to default skunk intensity of 21!
But when I set intensity to higher than that, my skunk hashing speeds just go slightly down from there.
Simply for me intensity of 21.0956 is the best possible maximum for skunk algorithm.

I mean intensity of 21.0956 mining skunk in tpruvot's ccminer 2.2, 32-bit, x86 version gives me about 59MH/s, sometimes it jumps even little bit over 60MH/s per 1080 Ti card in contrast to plain default intensity of 21 which gives just about 2MH/s less with the same OC settings. I described my OC settings some posts ago.
Skunk hashes on my Aorus 1080 Ti Xtremes faster with overclocking/underclocking at core +120 (1841MHz) and memory -2000 (9010MHz) with power limit at 85%.

Also compiling tpruvot's ccminer 2.2 with CUDA 9 gives a little bit better performance.