getting an imac5k

I would suggest building your mac with 8GB of RAM and upgrading using 3rd party RAM. Its cheaper.

 

What games are you trying to play? It sounds a bit overkill in my opinion, if all you are doing is using photoshop and playing games

 

I suggest OWC (MacSales) or Amazon.com. The RAM is user accessible so it should not void the warranty.

 

Installing the correct RAM will not void your warranty.

 

Are you serious? 'Playing games' is the most demanding task the Mac will do in everyday use! There is no such thing as 'overkill' when it comes to games!

 

A 2TB Fusion Drive is physically a 2TB spinning hard drive as well as a 128GB SSD (very fast flash memory). This two drives are then 'fused' via software to act as one drive. The operating system (OS X) will then decide which data to place on the slower HDD and which to put on the much faster SSD, to give the feeling of a very fast and responsive system. And in my experience it works very well. However, when you install Windows via Boot Camp it only installs on the HDD part of the Fusion Drive, meaning the speed benefit you will get in OS X will not be present in Windows. The easiest way of getting around this is to buy a machine purely with SSD. That way you can have both OS X and Windows on the fast SSD.

 

You can get away with an average iMac model, but run windows on it. You don't need 32 gigs of ram, you don't need an i7, and you don't need the gpu. But if you want all of that stuff, I am not going to stop you. But it is a waste of money. What you need is 8 gigs of ram, an i5, an ssd or hdd (no fusion), AMD Radeon R9 M380 graphics processor with 2GB of memory.

Just please remember to dual boot Windows on there, games will run 100% better and you will be much much happier. OSX is not designed for games, thus why no modern games are built for osx

 

If you want my advice, ignore the advice from shftoptk. I think he is trolling. The i7 and M2395X make a big difference in gaming performance. Look at this link http://barefeats.com/imac5k15.html and you will see the performance of the 395X compared to the 380 in games.
As for Bootcamp, definitely not necessary. The only time I use Bootcamp is when there is no Mac version of a game planned, e.g. Witcher 3 or Fallout 4.
There are loads of games for OS X, just look on Steam. Some games I have played over the last year or two on OS X are:
XCOM 2
Deus Ex Human Revolution
Shadow of Mordor
Talos Principle
Layers of Fear
Tomb Raider 2013
Thief 2014
GRID: Autosport
Call of Duty series (some)
Max Payne 3
Elite Dangerous
Hitman Absolution
SOMA
Walking Dead
Bioshock Infinite
F1 2013
Dirt 3
Company of Heroes 2
Spec Ops: The Line
Borderlands 2
Left 4 Dead 2
Empire: Total War
GRID 2
XCOM Enemy Unknown
Metro 2033 and Last Light Redux.
As for running'100% better' in Windows than OS X, well, it's simply not true. Yes, there is a performance improvement in Bootcamp, but, in my opinion, not so great that it merits booting in and out of Windows and out of the environment that you have paid for, i.e. OS X.
Your original suggested spec is almost the same as what I have, and I can assure you that I am very happy with it and all the games I play on OS X!

 

They swap between AMD and NVIDIA GPU's depending on what is available and provides the best performance/power/heat efficiency at the time of release. The next iMac could well have an NVIDIA GPU.