Late 2013 base 21.5" vs base 27"

I can't find any good online comparisons between the two base models of the late 2013 iMac (21.5" vs 27")

Trying to help someone decide and I'm looking for what the performance difference is.

Both would be upgraded to the 512GB SSD and both would have 8GB of RAM. (I know the 27" allows user to replace RAM and that's nice....but 8GB should be fine for their usage).

As for the screen size....it's a toss up. The person doesn't NEED a 27".

Light usage, spreadsheets, web browsing, iPhoto.

I'm trying to get a sense on how the CPU and video card compares between the two.

Money aside.....is it worth it to go with the 27"? It's about $500 more.

Thanks!

-Kevin

My biggest problem is the person really doesn't need a 27" screen. She does mostly web browsing, email and spreadsheets. So I can imagine her loading all windows up in the middle of the 27" with wasted space on either side.

After looking at Geekbench....I see the CPU differences are pretty minimal between them:

3131 (21.5") and 3547 (27") for single core and 10213 and 11267 for multicore.

No idea on the GPU...but I'm guessing the 27" needs the dedicated to drive the big display. Again....she won't be gaming, so no real need.

I guess with the Geekbench numbers my question is kind of answered. Just wish Apple allowed RAM upgrades on the 21.5".....don't want to drop another $200 for RAM if it'll never get used.

-Kevin