At work, I use my laptop (a reasonably new Dell Latitude 5490 with Windows 10) connected to a Dell WD15 dock. With the laptop screen closed, this drives a single Samsung S23C650 monitor at 1920 x 1080 pixels, through the dock's Mini DisplayPort. The display is nice and clear enough to do my work.

I have now acquired another S23C650 monitor and I want to connect it through the dock to achieve an extended display of 2 x (1920 x 1080 pixels). The monitors have VGA, DVI-D and DisplayPort sockets - no HDMI.

I've tried an analogue VGA cable, but the display on the second screen is noticeably 'fuzzier'. So, I'm wondering how best to connect the 2 monitors through the dock:

  1. I could get a VGA to DVI-D connector, but would that make it less 'fuzzy'? Or how about a VGA to DisplayPort adaptor, if such a thing was possible?

  2. Several forums on the internet suggest a HDMI to DisplayPort adaptor might work, but others say there is no such thing and instead I would have to go to via a DVI adaptor anyway. So I could go HDMI to DVI-D to DisplayPort. But if I'm going to do that, why not stop at the HDMI to DVI-D. Would any of these solutions make the second screen less 'fuzzy'?

  3. Amazon also sells a number of DisplayPort splitters, where 1 mini-DP is split into two through a little box. But these are quite expensive compared to various cables (typically £50+) and I am unsure whether they would allow the extend display I want.

Update: I acquired a HDMI to DVI-D cable. While the display was less fuzzy, it introduced strange artefacts to the text displayed on both monitors - every few millimetres the verticals of letters seemed to be double-width. In effect, the display on both monitors was worse than the slight fuzziness of one monitor using the analogue VGA connection. I got the impression that it would start to induce headaches after some hours, so I've gone back to using the VGA cable for the time being.


DVI-D is compatible with HDMI in many cases and should not require any kind of signal conversion for the use you describe. "So just stop there."

"To promote interoperability between DVI-D and HDMI devices, HDMI source components and displays support DVI-D signalling. For example, an HDMI display can be driven by a DVI-D source because HDMI and DVI-D both define an overlapping minimum set of supported resolutions and frame buffer formats."

There are potential limitations like hdmi copy protection handshaking, bandwidth (1920x should be fine), etc. but a simple hdmi-to-dvi-d adapter should work. These are often bundled with graphic cards.

  • 2
    It might be worth mentioning that anything involving an analog VGA link is going to be fuzzy relative to a pure digital connection. – T.J.L. Dec 11 '19 at 18:33

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