IQ is not a well defined thing, so to give a precise answer, we need a definition.

I would say that IQ is measuring very accurately only one thing: itself! IQ is measuring IQ, and that this measurement doesn't tell anything else. Just like arm wrestling doesn't measure strength, but measure arm wrestling capacity. IQ measures just IQ capacity.

That being said, is it possible to have a poor memory and a very high intelligence?

I think so.

You see, memory and consciousness are linked very much with a vertical linear processing capacity, it's a way to see a world that is evolving into time, hence memorisation. A CPU in a computer is working that way.

But creativity and intelligence are linked, when you search for understanding, you search for finding patterns, and that is more of an horizontal parallel processing capacity. A GPU is working that way.

A CPU is a big engine that goes fast but straight forward, when a GPU is a large set of simple slower engines that do everything in parallel, it's what we use to display graphics.

Most artists are well know to have memorisation issues. I'm not saying that all artists have high intelligence, but I do think that high intelligence always implies the artistic capacity.

True intelligence always leads to creation, that's why it can't really be measured.