[NAME]  Your XPS 8700 is the same vintage as my XPS 8900 and came with the same graphics card and monitor.  As I remember, my computer also came with a DP to mini-DP cable, which I used to connect the screen to the motherboard panel DP connector.  Your computer also has a DP connector on the motherboard panel.  If you still have the cable somewhere, you could try using that.  Otherwise, a DVI-D to either HDMI or DP cable will probably be the best option, allowing both monitors to connect to the graphics card.
Hello, I have an XPS 8700 desktop. I bought it with a 24" U2414H monitor that connects to an NVIDIA GeForce GTX 745 graphics card via the HDMI port. I recently bought a Dell monitor - S3220DGF to use as with my existing monitor. The graphics card has only one HDMI slot. I tried an HDMI splitter, but it displays the same single monitor info on both. I tried using a connector to go from HDMI to VGA as I know the VGA input will work for my second monitor.  But the monitor connected to the HDMI to VGA cable is not detected. Is there another workaround to get the two monitors, neither of which have VGA connectors, to get this to work? Thanks!
Set up XPS 8700 with dual hdmi monitors with VGA