Why does the Micosoft Update slow down my computer?

I run Microsoft's Autoupdater, which checks for and prepares me for updates every week.

Unfortunately, it manages to do so at my expense!

Usually, I catch it, but this time I didn't see the little window and I was distracted with some other, newer applicaitons I had installed (Kaspersky). Sill me, I focused too long on the anti-virus software and neglegleted what has become a small nightmare, for me. My bad, but still, should any background application be able to co-opt the whole system like this?

How can I change the priority on Microsoft's Update application so that it can't pre-empt everything else?

Is there some other way to tune or modify this app, without just turning it off?