The car has electronic power steering, so no fluid or pump to worry about.
I'm guessing you mean really slow like when you're doing manoeuvres and stuff, like parking?
It's speed sensitive, so it electronically senses your speed and adjusts to suit. So, heavier when travelling fast and lighter when travelling at slower speeds. From my experience though, it gets confused at really low speeds and randomly becomes heavier for a moment, before lightening up once again. I've found this when parking or doing three point turns and such. Just gets really heavy all of a sudden, but then sorts itself out shortly.
I don't think it's a problem with your car at all. Just something that we have to deal with. Hope this helps!
1998 Daihatsu Mira L512 TR-XX Avanzato R4
1998 Toyota Soarer JZZ30
1996 BMW E36 Compact