UserAgent: Mozilla/5.0 (Windows NT 6.3; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.110 Safari/537.36

Steps to reproduce the problem:
Enable in flags
Restart browser
Use it :)

What is the expected behavior?

What went wrong?
This is not a bug as such but just providing feedback in case there is a proposal to make this backend the default.

I read the page describing this feature which would indicate it would perform faster due to some overheads been removed, but I have observed it is actually slower when the cache is heavily populated.

The 2 tell tale signs are if I manually clear the cache after heavy use, on the default cache it takes under one second, in the Simple Cache for HTTP it takes over 10 seconds.

The other sign is web browsing the rendering of pages is visibly slower when the cache is heavily populated, after I cleared the cache, and then on second load of page (so cached) its snappy again.

Did this work before? N/A 

Chrome version: 58.0.3029.110  Channel: stable
OS Version: 6.3
Flash Version: n/a

So I suggest keeping this as experimental :)