Comparing performance measures of different architectures is hard, or even useless, because they are not the same.
In that sense, even IQ is debatable whether it really represents anything. Some IQ tests include language, numbers, etc. Does it also mean that people who have dyslexia or dyscalculia are dumber? I doubt both should have an effect on the score, however, the way they consume and process information is 'different'. Herein lies a crucial observation that expressing IQ as a scalar value is kind of useless: some people have perfect memory while others can string together many different concepts while needing to look up everything they use.
As far as I read into, I believe that IQ is a weighted average of several of these factors. Important pillars of good IQ performance are then short and long term memory and the ability to associate different concepts with the observations presented at present time. I think the latter is quite a fundamental measure of 'brain performance', as learning and understanding is basically all about it.
Then trying to compare brain vs computers becomes hard. Computers have memory storage expressed in bytes and computational power often expressed in FLOPS. However, in a sense even our human cognitive computations are also associations. We have learned that the numbers go like [1, 2, 3, 4], etc. and we have learned what the mechanics of addition, subtraction or multiplication is (e.g. that 2-1=1). However, if one had learned that numbers went like [1, 3, 2, 4], then he/she may still be able to perform computations quickly (e.g. 2-1=3), but perhaps not correct to our typical conventions. Likewise in computers, 2's complement is not the only way of storing an integer, and relearning number systems and observing redundant number systems is quite an interesting philosophy on how we can treat computations more efficiently.
What I mean to say is; the concepts we treat as cognitive computational power are, in a sense, also memory lookups of a convention that we take for granted. The brain is a huge association machine, which is more like a massive FPGA with lots of block RAM spread around..
In terms of the processing the brain does to give us consciousness is far in excess what a typical computer will do, especially relative to the energy the brain consumes. If you only look at the visual cortex and the speed at which we recognize objects at different illumination levels, orientations and shape variants... it's very very impressive. We probably need far far more powerful computers to even come close to matching it.