P3DV3 Using Wrong AM?

[TheBoom 31]

So I have been tinkering with the AM since 3.1 to see which fits my system and configuration best. I've noticed a oddity with setting the AM though.

 

If I use an AM of 248 (11111000) the cores used in reality are 11101000. 

 

Same for 252, the core after the main thread is not used by the sim (11110100 instead of 11111100).

 

The way to fix this is to go into the task manager right-click and click change affinity then simply press ok without changing anything. Now, this fixes the problem and the sim starts using the core previously not being used. However, it creates another anomaly where the main thread no longer works to 100% and I believe it is also causing sudden VAS spikes.

 

Is this normal behaviour or is there something wrong here?

 

This issue has actually been there with 2.5 as well but I was not really bothered by it so much since I was running much lower settings. It's also probably not the processor as I had it with my 4770k previously and now with the 6700k.