-low / -high only modifies the priority of the process. This probably won't help you much as the scheduler will still give the compile tools all the processor time they ask for, if there aren't any other CPU intensive applications running at the same time. You could try limiting the number of threads by using the -threads # parameter. I.e. -threads 1 to limit it to one thread only. Use a value lower than a number of logical cores of your CPU.
There are many other ways to limit the CPU usage - either globally or on a per-process basis. On Windows (I assume that's what you are running) you can change the "maximum CPU frequency" or "maximum CPU state" in Control Panel -> Power Options (this is a global setting).
No matter what method you use, the compilation process will of course take longer than it did before.
80 °C certainly isn't an ideal temperature to have the CPU running at, and depending on the model of your CPU it may or may not be within the allowed range. Either way you should fix or replace your cooling solution if possible (unless this is caused by an abnormally high ambient temperatures or something).