Dell Monitors only support a maximum resolution of 1920x1080 or 1920x1200 when connected to certain Inspiron, Vostro, and OptiPlex computers using an HDMI cable.
原因
Affected computers:
Inspiron 15 7579 2-in-1
Inspiron 3493 Notebook
Inspiron 3501 Notebook
Inspiron 3502 Notebook
Inspiron 3505 Notebook
Inspiron 3520 Notebook
Inspiron 3593 Notebook
Inspiron 3793 Notebook
Inspiron 3891
Inspiron 5493 Notebook
Inspiron 5593 Notebook
Inspiron 3910 Desktop
Inspiron 3020 Desktop
Vostro 3400 Notebook
Vostro 3401 Notebook
Vostro 3405 Notebook
Vostro 3420 Notebook
Vostro 3430 Notebook
Vostro 3491 Notebook
Vostro 3500 Notebook
Vostro 3501 Notebook
Vostro 3520 Notebook
Vostro 3591 Notebook
Vostro 3671 Notebook
Vostro 5568 Notebook
Vostro 3267 Desktop
Vostro 3471 Desktop
Vostro 3710 Desktop
Vostro 3910 Desktop
Vostro 3020 SFF
OptiPlex 3000 Desktop
Vostro ChengMing 3900
Vostro ChengMing 3901
Vostro ChengMing 3901
解決方法
The computer is working as designed.
The HDMI connector cannot output a resolution higher than 1920x1080 or 1920x1200 on the motherboard used in these Inspiron, Vostro, and OptiPlex computers. (Depending on the model.) This is the motherboard working to the limits of its design.