iMac 27" late 2013 run an external monitor at 4K on 60Hz?

yes you can. but the imac late 2013 27" is the first model of the imacs which is capable of 4k at 60Hz, lower dates (mid 2013 or early 2013 or even lower) cant support 4k at 60Hz.

but it strongly depends on your OS and 4k Display type.

with the latest OS 10.11 or 10.12, 4k/60Hz over Displayport or MiniDisplayPort is supported.

lower systems like 10.8 or 10.9 dont support 4k at 60Hz.

"With OS X Yosemite v10.10.3 and later, most single-stream 4K (3840x2160) displays are supported at 60Hz operation on the following Mac computers:"

- imac 27" late 2013

that could mean that if you buy a multistream 4k display, you could only get 30Hz, which could result in mouse lag or other lags.

so whats left, is to find out, if your desired display is a SingleStream or MultiStream Type.

i hope i summed it up correctly. if not, please correct me.

thanks

Hello JHyde01,

Thanks for using Apple Support Communities.

If you want to use a 4K display with your Mac, the displays are limited to a Maximum of 50Hz on one specific model as shown below.

You can use 4K displays and Ultra HD TVs at the following resolutions and refresh rates via the built-in HDMI port.

• 3840 x 2160 at 30 Hz refresh rate
• 4096 x 2160 at 24 Hz refresh rate (mirroring is not supported at this resolution)

With OS X Mavericks v10.9.3 or later, the following DisplayPort displays are supported at their default using single-stream transport (SST) at 30Hz.

• Sharp PN-K321
• ASUS PQ321Q
• Dell UP2414Q
• Dell UP3214Q
• Panasonic TC-L65WT600

With OS X Yosemite, you can use all of the above displays as well as the following:

LG 31MU97 4K display (at 30Hz or 50Hz)

Other Mac models do support MST displays at 60Hz as shown below.

MacBook Pro (Retina, 15-inch, Late 2013, Mac Pro (Late 2013), and iMac (Retina 5K, 27-inch, Late 2014) computers also support multi-stream transport (MST) displays at 60 Hz. If you use a 60Hz MST display with the MacBook Pro (Retina, 15-inch, Late 2013) or iMac (Retina 5K, 27-inch, Late 2014), only one additional Thunderbolt display can be supported.

Using 4K displays and Ultra HD TVs with Mac computers - Apple Support

Take care,

Alex H.

Did you ever get it working? I would like to hook up on my 27" iMac late 2013 2 4k display 3840x216 @60Hz, but I don't know if it can even work