Fortunately there exists a tool you can download, made by HSMWorks, specifically for benchmarking CPU performance when calculating CAM cutterpaths. Like HSM CAM software, this benchmark takes advantage of multi core calculations. This benchmark has been around for a few years, but is still applicable to hardware today, and successfully runs on Windows XP to Windows 10.
You can visit the HSM CAM forums thread where others have shared their results from this benchmark and the hardware they are using.
Reasonably fast laptop:
Here is the result of a Dell M6800 laptop with a 5th generation core i7 with a base CPU clock of 2.9Ghz. The overall rating is 650, where the higher the number the better.
An even Faster Desktop:
Here is the result of a 4th gen Intel i7 4790K cpu with a base clock of 4.0Ghz. This one topped out at a rating of 740 (more on that later)
DDR3 Memory vs DDR4:
We had access to one of the latest Intel CPU's, the 6th gen Intel i7 6700K. This is not an exact apples to apples comparison to the one above, but it's as close as we can get. The CPU is one generation newer, at the same 4.0Ghz clock speed, but with DDR4 memory instead of DDR3.
Interestingly, the score was 905, a full 22% improvement. Likely due in large part by the newer chip architecture, and also in part by faster memory. Knowing which did how much in this particular test is beyond the scope of our Saturday fun.
Different CAM systems are better than others at utilizing multiple core CPU's. In the event of HSM, it is designed very well for multi core computing. In fact, a 12 core system (6 cores hyper-threaded), running at 20% lower clock cycles will generally outperform the 8 core system (4 cores hyper-threaded).
Prior to this 4.0Ghz DDR4 i7 machine, the previous record holder on the forum was a 12 core system from 2.5 years ago, with a score of 834.9, faster than the 4.0Ghz DDR3 machines best score. The take away here is that more cores are better, at least on well optimized software.
One interesting thing we discovered was a lot of variation in the score on the 4th gen 4.0Ghz 4790 chip. One time the score was 740, other times 710, then 705, then 715, etc.
What we discovered was that at times, it was not running all 4 cores at the maximum speed all the time. Sometimes it would drop the speed of the individual cores during extreme calculations, based on the temperature of the CPU.
This begs the question, what would happen if we installed a better cooling solution on the CPU? in the pictures below, the one on the left shows the default heat-sink and fan on the CPU. On the right, we installed a simple all-n-one water cooling solution to the CPU. This utilizes a larger fan, radiator, and water cooling.
The immediate benefit is that the better cooler allowed the CPU to stay at the maximum speed, all of the time. The throttling of the speed stopped, allowing for the maximum performance all of the time. From there, for those that are comfortable, you can apply a slight overclock for even greater performance.
Overclocking the 6th gen i7 just a couple percent allows for a pretty safe performance rating of 924.
The take away here is that if you don't have a decent cooling solution on your CAD/CAM box, you may not be getting the full performance, even if you don't overclock. While a water cooler may be overkill, make sure that you have a high quality cooling system on your CPU.
With well optimized CAM software, more cores probably provide the most bang for the buck, faster cores are better. DDR4 vs DDR3 memory may provide some benefit, but you have to switch out a lot of components to do this, at considerable expense.
However, to get the maximum performance out of your current solution, make sure you have a quality cooling solution.
Edited to fix some technical errors.
Edited to fix some technical errors.