To match the relatively old iMac models, it's advisable to select the 2560 x 1440 resolution on your PC. Don't forget to adjust the screen resolution for optimal display quality. Wait for a few seconds, and then you will see the PC screen mirrored on the iMac screen. It's also possible to press 'Cmd' + 'Fn' + 'F2' instead. Press the 'Cmd' + 'F2' on the iMac keyboard to trigger Target Display Mode. Then, connect the male end of the adapter to your iMac.(Use the adapter)

3. Connect the PC with the adapter using an HDMI cable.

2. Plug the end of a cable into the Thunderbolt port or the Mini DisplayPort of the iMac, and then plug the other end of the cable into the Thunderbolt or Display port on your PC.(Don't use the adapter).

Then, you can follow the steps in this post to connect and use an old iMac as a monitor. Yes, you can use the iMac as a monitor for a PC as long as the iMac offers a target display mode and the Thunderbolt port or the Mini DisplayPort. 'Can I use my iMac as a monitor for PC?' Many people are curious about this question. This new feature enables people to use the iMac as a monitor to display another device. In 2009, a new version of the iMac is introduced to users, and it's the first device with Target Display Mode. Ever since it was released in August 1998, the iMac becomes one of the most popular desktop computers worldwide, and it evolved into many different forms.

Late 2013 imac os