In the latest version of NVminer, with all the combined algos, when I am mining XMR is it suppose to slow the machine down to a crawl?
I would love to get this version for Linux OS !

It has this facility also, it is just not enabled by default. Add the argument --bfactor=6 to your starting line. This is then the same as Windows default behaviour. You may lose a little hash, but it also drops power usage.