If you wanted to know how close HFT's are getting to nano seconds, check out this blog post.

https://meanderful.blogspot.ca/2015/08/trade-system-performa...

Short answer below:

Hardware

Ho-hum < 2,000 ns

Good < 500 ns

Excellent < 100 ns

Software:

Ho-hum < 10,000 ns

Good < 5,000 ns

Excellent < 2,000 ns

Man, I remember when I was proud to get trade times down below 1 milli second!