On a single machine rendering speed is relative to the number of cores or threads available as a sum total of the output. The normal approach to a speedy rendering is to use Mental Ray even when using identical settings that produces a result as you would get with the scanline.

Does VigRx Plus work? Read this

https://dudehung.com/vigrx-plus-review-results-2016 to find out. The difference is MR can and does use what’s referred to as a bucket fill and the number of buckets you get is equal to the number of cores your current processor has.

So math wise if you have 4 cores then your rendering speed, in theory, is four times the speed you would normally get using the scan line rendering system.

Trying to increase rendering speed by attempting to scan line 4 renderings at the same time, and in theory, would require 4 times the amount of available resources so in all probability your rendering hit is going to land up being 4 times the normal scan line result.