"IQ" is a scalar semi-objectice well-defined metric that predicts some things about the much more complicated and less-well-defined concept of problem solving.

Problem-solving: the ability to deconstruct a problem into atomic pieces and construct solutions

IQ: How fast you do it.

tl;dr: Problem-solving is software, IQ is hardware

"IQ" measures something called "G", which is pattern-recognition ability (coincidentally the cutting edge of today's ML neural nets). The scientific theory of IQ is that that if you are good at pattern recognition, then you will be good at a wide range of cognitive tasks.