21/27 performance difference

Of course their will be a difference. 27 inch a lot more powerful and more future proof (RAM user-upgradable, 21 is not)

 

I wouldn't really agree. The i7 in the 21.5" (i7-4770S) outperforms the i5-4570 (3.2GHz) in the 27" because the i7 has hyperthreading.

 

Well seen as the upgraded imac with the 750m doesn't have an i7 that doesn't really apply. You can upgrade the 27" with an i7 too

 

The OP was thinking about the low end 27" with GT755M (refer to his original post). That isn't upgradeable to the i7-4771.

So I'm comparing the high-end 21.5" with i7 with the low end 27" the OP was thinking of.

 

Why are you guys talking about the CPU? The CPU has a minimal impact on gaming which was what the OP wanted to know. The OP clearly stated he/she wanted to know how the GT755M in the 27" would handle the 27" native resolution compared to how GT750M in the 21.5" would handle the 21.5" native resolution.

 

Super Tomtendo said about power (which includes CPU) being far better in the 27". I was just replying to his statement.

 

Without knowing any other details…

There’s very little difference between the 750m and 755m in iMacs, the latter is a little faster. Although I would expect the native resolution performance of the 21” model to be slightly better, my gut feeling it would be negligible in casual gaming (using Minecraft as an example) – also, reducing the 27”’s resolution wouldn’t be a problem, I feel,

Minecraft doesn’t exactly require much in terms of power to max out the graphics – there have been various discussion here in the past about performance and far older, less specced machines performed brilliant – and I suspect performance would be roughly equal.

Hyperthreading doesn’t help games (albeit in a very few isolated examples, I believe) and in some cases, IIRC, can be reduced performance ever so slightly – although that isn’t a cause for concern.

If the OP’s main concern is how well casual games play, I doubt that they’ll be using too many apps that would benefit from hyperthreading – but I could be wrong!

 

21.5 inch 1080p > 750m vs 1440p > 755m is probably a wash. The slightly faster GPU has to render more pixels. My son's mini with intel 4000 integrated gpu runs minecraft just fine at 1080p over hdmi. I'm quite sure either computer will work great....you just need to decide how much $$ you want to spend, vs what else you want to do with it.