I like to share something about margin trading.
Are you looking for a good place to margin trade bitcoin without lag?
Bitmex is the place for you. I am sharing it because it's a high-speed reliable system. Bittrex is slow compared to this.
You can trade up to 100x margin but I don't recommend to do more than 25x.
Users who signup under my link will receive a 10% fee discount for 6 months on Bitmex:
https://www.bitmex.com/register/dKbwMo
Take a look at the demo to see how fast it is.
Cheers.