You are probably noticing the difference in the actual gear inches caused by the difference in the wheel sizes. Often you'll see 650 bikes equipped with the same gearing as 700's, but the wheel size has an effect too. The same front/rear chainring combo was easier to turn on the smaller bike than it is now with your bigger wheels - but with the bigger wheels you travel further. This gets a little technical - but I've run it through a calculator. Lets say that all other things are equal - same front and rear gearing (I've assumed 53/39 front 12/25 rear), same crank length, just the wheel size is different.
on the 650 bike the smallest gear would be 39.94 inches
on the 700 bike the smallest gear would be 43.06 inches
(the smaller the number the easier the gear)
this means if you have the same gearing the 650 bike would actually have a "lower" gear and be easier to spin up that steep hill - but in that lowest gear for each pedal rotation the bike travels 10 feet 5 inches on the 650's and 11 feet 3 inches on the 700's.
the same things go for the bigger gears.
So in the real world this means on the 650 bike and it probably will be easier to spin up those hills, but on the flats where you are less likely to notice the difference in the gearing even though your cadence may have dropped a bit (as you are using "bigger" gears now) your speed may be up. In time you'll get used to it and you'll probably find you adapt which gears you are using to get the fast cadence back. You can also check out a gear inch calculator and see if you can change your rear cluster to get back some of the same ratios if you miss them.
I hope I've stated all of this correctly and it wasn't too confusing
