In The Laundry Files series by Charles Stross, "magic" is a branch of applied computation (mathematics), and computers can cast spells much more quickly and precisely than a human. Experienced sorcerers can run macros (cast spells) in their head, but it tends to cause Krantzberg-Godel Spongiform Encephalopathy with prolonged use. You also have to make sure your summoning circle is properly grounded, or else you might get possessed by a demon.