Havei got usb3

[fixerman]

I have a 2015 27 inch iMac. Has it got usb3? I've had a look at the usb inputs but there is no indication

 

[theMarble]

All iMacs since 2012 have USB 3.0, so yes all of your USB ports are USB 3.0.

 

[jz0309]

I have a 2015 27 inch iMac. Has it got usb3? I've had a look at the usb inputs but there is no indication

if you how further question re your iMac, check this: https://support.apple.com/kb/SP718?locale=en_US

 

[Fishrrman]

Yes you have USB3.

BUT... BE SURE that if you buy USB3 drives (such as SSDs), that you also use a USB3 -cable-.
You can distinguish these from older (USB2) cables -- the USB3 cables have a "blue tip" visible when looking directly at the plug.

Without a USB3-capable cable, the drive may run at slower speeds.