Just got brand new, highest end 2017 27" iMac - my thoughts and questions regarding gaming on it

I've had the machine for a few days now. It's the 27" inch model with the Radeon 580 8 GB GPU, Intel 4.2 GHz i7, and 1 TB SSD hard drive. I got it with the stock 8 GB RAM and bought another two sticks of 16 GB of RAM for a total of 40 GB of RAM (incredibly easy to do by the way - I've never done this with an iMac before and it took me literally 3 minutes).

I do software work for a living and use a Mac as my main machine. I do love gaming 1-2 hours a day and wanted to finally be able to use a Mac to game. So far it's worked well.

The performance when working is incredible. It indexes my projects literally 15x faster than my late 2013 Macbook Pro. I hooked up an external 4k monitor to it, and whereas my 2013 Macbook Pro would often lag when working with it (the CPU would have to constantly work at over 40% utilization just to keep rendering everything), there's no slowdown at all with my new iMac. The display is of course incredible, and the speakers are not bad at all.

I did run into some issues when installing Windows 10 via Bootcamp. I had forgotten what a pain in the ass Windows is. After Windows 10 was initially installed, the Bootcamp drivers for Windows started installing. And what does Windows do? Perform an update and restart that interrupted the Bootcamp driver installation which totally fucked up everything, forcing me to delete the Windows partition and re-do everything over again from scratch. So advice to anyone out there, do NOT let Windows perform an automatic update after it's initially installed. Let Bootcamp install first, otherwise you won't have the proper driver setup. After Bootcamp is installed in Windows, THEN let Windows update.

After Windows is installed, you can get back to Mac OS by going to the Bootcamp control panel accessed in the lower right taskbar and choosing to restart in Mac OS. If it's not there, Bootcamp didn't install successfully (happened to me the first time when Windows updated while Bootcamp was trying to install). You can also restart and hold down the option key to get a prompt allowing you to choose if you want to boot into Mac OS or Windows. When you're in Mac OS and want to boot into Windows, this is how you do it - just restart, and as soon as the cursor disappears start holding down the option key until the boot device prompt appears.

It takes less than a minute to restart the machine and be fully ready to go in Windows, and vice versa. Very quick.

Ok so on to the gaming experience thus far, while booted into Windows 10. Overall it can play any modern game at high settings well at 1440p resolution, usually at 60 FPS. Turning settings up to max will cause the machine to struggle at 1440p (still playable depending on the game, but definitely not 60 FPS) and you might have to game at 1080p if you want to play games at max settings while still getting 60 FPS.

My FPS in the Witcher 2 never drops below 50 FPS even during intense combat. 95% of the time it's at 60 FPS. I'm playing at 1440p resolution with High settings. Outside of combat it never goes below 60 FPS. Except there seems to be an odd bug when I access the menu sometimes, it causes the FPS to drop to about 15 until I re-access the menu. Kind of annoying but it's clearly an issue with the game itself and not the machine, as my temps don't even get that hot when this happens. I'll have to try the Witcher 3 next, but it should handle that game admirably as well.

I played Fallout 4 and Mass Effect Andromeda at high settings at 1440p. I also am getting usually about 60 FPS, it might drop down to the low 40s in rare circumstances which is still playable. I cranked up the settings to the max and I was not getting a smooth 60 FPS, and FPS dropped into the 20s at some points.

I should note that you can hook up an external GPU via Thunderbolt 3 to this without issue (in Bootcamp/Windows 10 at least - I've heard people say they have some issues getting it to work while booted into Mac OS), so if you have the money to spend on a Bizon Box and a GTX 1080ti (the Bizon Box itself costs as much as a decent gaming PC minus the GPU, just FYI, but you can't use the iMac's monitor with an external PC) you'll of course be able to handle any game at max settings with smooth framerates, maybe even at 4k resolution. I haven't done it but that would be my guess.

CPU temps reach about 200-210 F after a couple hours of gaming. The fan dissipates the heat well and never gets too loud. No performance throttling. The Bootcamp drivers make sure that the fan runs at just the RPM it needs to dissipate the heat.

So this is not a beast of a gaming machine, but it seems to offer performance about on par with a PC equipped with a GTX 1070 which is still very powerful. This is probably the first time Apple has come out with a machine that can actually handle modern games this well at a high resolution without throttling - I was so afraid I'd have to get a separate gaming PC to game. So it should be able to handle any modern AAA game you throw at it in 1440p as long as you're not on max settings. If you want to play at max settings and still get 60 FPS you may need to game at 1080p resolution instead.

Gaming on the iMac screen is of course gorgeous.

I do have one question perhaps someone can assist with.

I often times would prefer to game on Mac OS itself without having to fully boot into Windows. I know using Bootcamp offers the greatest performance, but what if I want to play an older game when I get a few minutes of downtime during the work day? I'd prefer not to have to exit out of all my work and restart in Windows unless I'm done with my work for the day. Would Parallels be a good option? Is there another option I might consider? I'm assuming I could use the same product key I used for the Windows 10 Bootcamp installation?