Which new iMac: Upgraded 21.5-inch or entry-level 27-inch?

depend on if it's i5 vs i7 cpu

and depend on the video card a nvidia or amd video card

8gb vs. 16gb depend on what apps and how many are running at the same time

having much unused memory does not make a compute rfaster it's running out of memory which makes it slower

fusion vs. std, fusion is close to the speed of real SSD so much faster then a normal hd to launch apps and to change from 1 user to another

I went from 4GB which was very slow from a cold boot when it got running it was much better but it to a long time before it was not slow

upgraded to 16GB and it has helped a lot but I'm pretty sure that the step from 4 to 8 would have been 80% and the step from 8 to 16 is only 20% can see using various memory programs that most of the usage these days is filecache which is pretty much what most operating systems use unused memory for

I bought the 21.5" a month ago because it used to be possible to upgrade their RAM. I ordered the DIM cards and went to look for the panel underneath to upgrade it, and there was no panel. I then went to remove the glass screen since that was do-able, and now it is sealed by glue. So, there is no way to upgrade the 21.5" unless you do so at the exorbitant Apple rates. I returned the 21.5 and left with a 27". I upgraded it to 32 Gigs of sweet sweet RAM at a fraction of the Apple cost. From practical experience, I would say to go with the 27".

I went with the standard 1TB hard drive. Why spend more on a hard drive? The processor isn't noticeably different. I can feel the power of the RAM though.