Technical white paper - Three-display support with the HP Compaq Elite 8300 Ultra-slim Desktop PC

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Other limitations
Using an HP DisplayPort-to-dual link DVID adapter is not recommended in a three-display configuration. The DisplayPort
connector controlling the adapter will have limited bandwidth, restricting the adapter to supporting modes of
1920x1200@60Hz and lower. DVI-capable displays of 1920x1200@60Hz and lower resolutions do not require dual-link
DVI support. Most high-resolution displays requiring dual-link DVI do not support many resolutions lower than their
native high resolution. Configuring three such displays using a DisplayPort-to-dual link DVID adapter would result in a
potentially unacceptable experience.
DisplayPort adapters like HP’s DisplayPort-to-VGA adapter are active adapters and communicate to the system using
DisplayPort protocol. DisplayPort adapters like HP’s DisplayPort-to-DVI and DisplayPort to HDMI adapters are passive
adapters and communicate to the system using TMDS protocol. The system has limitations depending on which type of
adapter is used.
If one or two displays are connected to the system with an HP DisplayPort-to-DVID adapter, HP DisplayPort-to-HDMI
adapter, or any other similar passive DisplayPort adapter, the system will be limited to supporting only two active
displays. If three displays are connected, you can use either the Intel Graphics Control panel or the operating system’s
display controls to select which two displays are to be active. Once two of three connected displays are enabled, one
display will need to be disabled before another can be enabled.
In a three-display configuration, both Display Ports must use DisplayPort protocol and operate at the same link rate.
Support for three displays is limited to configurations with a display connected to the system’s VGA connector via a VGA-
to-VGA cable plus one or more DisplayPort-capable displays connected with DisplayPort-to-DisplayPort cables or one or
more VGA-capable displays connected with a HP DisplayPort-to-VGA adapter. In these configurations, each attached
display will be limited to a maximum of 1920x1200@60Hz resolution due to the processor’s internal hardware
resources being shared by all three display outputs. All 3 displays can be enabled by using either the Intel Graphics
Control panel or the operating system’s display controls. See Table 1 for a summary of 3-display configurations.
NOTE:
It is possible to have a three-display configuration consisting of one DisplayPort display capable of higher than
1920x1200@60Hz support (like 2560x1600 or 2560x1440), one 1920x1200@60Hz DisplayPort display and a VGA
monitor with up to 1920x1200@60Hz support. Both DisplayPort monitors must be connected with DisplayPort-to-
DisplayPort cables and operating at the same display port link rate. For this configuration, the 1920x1200@60Hz
display must support the 2.7Gbits/sec DisplayPort link rate that the higher resolution display will require. With some
exceptions, HP DisplayPort monitors with 1920x1200 and lower resolution do not support the higher 2.7Gbits/sec link
rate since the lower 1.62Gbits/sec link rate suffices for this resolution.
If a system is configured with a display connected to the system’s VGA connector using a VGA-to-VGA cable plus one or
more DisplayPort-capable displays connected with DisplayPort-to-DisplayPort cables, we recommend that both
DisplayPort monitors be the same type/model to ensure that they operate at the same link rate.
Table 1: Summary of 3-display configurations without MXM graphics installed
DisplayPort #1 (top) DisplayPort #2 (bottom) VGA port
Result
DP DP VGA All outputs active [1]
DP DP-VGA VGA All outputs active [1]
DP DP-DVI/HDMI VGA Only two displays can be active [2]
DP-VGA DP VGA All outputs active [1]
DP-VGA DP-VGA VGA All outputs active [1]
DP-VGA DP-DVI/HDMI VGA Only two displays can be active [2]
DP-DVI/HDMI DP VGA Only two displays can be active [2]
DP-DVI/HDMI DP-VGA VGA Only two displays can be active [2]
DP-DVI/HDMI DP-DVI/HDMI VGA Only two displays can be active [2]
NOTES:
DP: Directly connected Display Port monitor
DP-VGA: VGA monitor connected with DP to VGA or other active DisplayPort adapter
DP-DVI/HDMI: DVI-D or HDMI monitor attached using a DP-to-DVI-D, DP-to-HDMI, or other passive DisplayPort adapter
VGA: Directly connected VGA monitor
[1] All three displays are limited to a maximum resolution of 1920 x 1200.
[2] Intel Graphics Control panel or the operating system’s display controls must be used to select the two active displays.