I was doing a job yesterday in which the new machines (Dell T1500) arrived and I set them up but could not get the dual screens to work properly. The guys are financial traders so they really do need the 2!
I could get the computer to recognise both monitors but it would only let me either use 1 or the other on it's own OR use both but just in cloned screen mode (shows the same on both screens). I could not get it to show a single desktop across both screens. In the control panel it did not let me have the option to show the large 1 or 2 on the screens as normal to help identify which was which.
The new machines have an NVIDIA Quadro FX 580 with an 2xDP (look like HDMI but Dell call them Display Ports?) and one DVI output (I think this may be a Dual Link DVI - not sure if you just use a splitter of some sort with this?. The monitors are both VGA (Dell too) and we previously used a VGA-DVI adapter on one and had a VGA connector hanging out from inside the PC for the other. The help in Windows (XP SP3 btw) mentioned at least one must be VGA but I am not sure about that as Dual DVI units have worked on other systems we have installed.
The mobo also seems to have another DVI output on it which does work but as I mentioned I can only do the Cloning - not proper dual monitors.
Those are indeed Display Ports, not HDMI. Very similar physically, but very different. You can use them with monitors that support DP connection. Otherwise DP-to-DVI is required. I don't think DP-to-VGA is possible, could be wrong. The DVI port is just a single monitor DVI, cannot use splitter to support 2 monitors.
You can use any two (out of three ports) at once, then chnage the display setting to something like "Extended Display", instead of "Mirroring".
Two DisplayPort and one Dual-Link DVI-I:
Only two of the three connectors are active at a time
2560 x 1600 maximum digital resolution for DisplayPort and Dual-Link DVI-I connectors
DVI-I with DVI-to-VGA monitor adapter allows attachment of a VGA analog to DVI-I monitor port
2048 x 1536 maximum analog resolution
DisplayPort with DisplayPort monitor cables:
DVI-D digital and VGA analog monitors attach via a DisplayPort Monitor cable:
DisplayPort to Single-Link DVI-I Monitor Cable allows attachment of a DVI-D digital monitor to DisplayPort
DisplayPort to VGA Analog Monitor Cable allows attachment of a VGA analog to DisplayPort
1920 x0 1200 maximum resolution
For more information on DisplayPort monitor cables, go to www.lenovo.com/support/monitoraccessories