How to make NVidia GT220 use IRQ instead of polling to detect Vertical Sync when Vertical Sync mode

Does NVidia GT220 use polling or IRQ to detect Vertical Sync when Vertical Sync mode is turned On?
It seems to me, that it uses polling because turning On Vertical Sync mode causes 100% load of one thread of Intel i3 processor.
If I am right, then how to make NVidia GT220 use IRQ instead of polling to detect Vertical Sync when Vertical Sync mode is turned On?