According to the documentation, a 3 monitor setup is possible and can provide up to 1080p resolution on each channel (VGA, HDMI and DP)
I tried to set it up this way only to end up with HDMI and DP producing 1080p but the 3rd monitor on VGA only getting a 640×480 resolution.
Suggestions?
What is the source you are using?
Under SST (Single stream) you are able to get 3x1080p (mirrored) displays,
Under MST (Multi stream) you are able to get 3x720p displays. Getting 2x1080p + 1x480p is correct due to limitations on bandwith,
You may need to do some math
https://insights.club-3d.com/thread/csv-1568-second-hmdi-screen-only-vga-res/
The CSV-1564 only supports 8.64 Gbps of DisplayPort 1.2 bandwidth. It doesn’t support DSC. DisplayPort 1.2 supports RGB, 4:4:4, and 4:2:2, but not 4:2:0.
1080p60 is between 133.32 (CVT-RB2) and 148.5 MHz (HDMI 1.1).
You need to lower bandwidth of each display by reducing refresh rate or bits per pixel.
Insert Image