[lossolo]

PHP 5 is allocating memory differently from PHP 7. That's why you see difference there and this is the biggest difference between E5 and E3 here (memory bandwidth,cache size). PHP 7 is making optimizations making less memory allocations because it allocates in chunks, PHP5 is allocating/reallocating all the time.

[TazeTSchnitzel]

Yep: http://www.slideshare.net/nikita_ppv/php-7-what-changed-inte...

[erichileman]

Memory seems likely.

On the E5 php 5.6 in top we see sys at 15%.

On the E3 php 5.6 in top we see sys at 7%.

On the E5 php 7 in top we see sys at 13%.

We are exploring memory perf more now.