holy puddle ducks i didn't check mine until i read your post and i tried this while running IM2 and, holy puddle ducks, it was spiking all 4 cores my i5 6500 up to 60% and back down to 11% about every second or two. it just looked like a spike pit. the second i closed IM2 it went back down to its normal 7% to 8%. i would say yeah, input mapper really eats the cpu whether i'm emulating or not. tried moving the controller around to get it to process the gyros to see if that would change the spiking but it was just a consistent 60%-11%ish spike pattern regardless of input. interesting...
hmmmm. the results are interesting. i was going to post a bunch of screenshots as i disabled each plugin but i'm an idiot and pressed Alt+printscreen instead of Ctrl+printscreen, thus taking a bunch of windowshots without the cpu window visible. but that won't be needed anyway since, as can be seen in my 2 properly taken screenshots, none of the plugins are the culprit for IM2. sorry OP since this doesn't necessarily address IM 1.6.7. here we can see that IM2 is the culprit.
if i was nice i would uninstall IM2 and re-install IM1.6.7 just to test this out for OP, but i'm not nice. also, while we're on the topic, do the older IM1.6.X have plugins? does the older version of imputmapper accept devices better? i couldn't get it to pick up a couple things i had plugged into my computer such as the playstation move nav controller (the controller without a lightbulb on top) and my 3dconnexion mouse. wobbles is currently helping a few of us in another forum specifically with IM2 and 3Dconnexion.
another question, can i have both IM1.6.Newest and IM2.Newest installed at the same time without any problems? as long as they are not both running at the same time? that would be great for experimenting since i have been uninstalling and reinstalling each as i switch back and forth between them. i've been primarily focused on 2.0 the past few days since i couldn't find a plugins thing in 1.6.