How much dps does haste add?

[Legidias]

If you drive 60 miles in 60 minutes, it's 60 mph, yes?

If you drive 60 miles in 30 minutes, it's 120 mph, yes?

Lowering the time to reach your destination by 50% also means your speed increased by double

Now replace miles with dmg/hp and minutes with seconds and you have DPS.

OFC if you are using procs / other things to boost damage, it doesn't apply, but I don't think anyone is taking that into account with haste. It's just raw physical DPS.