HP Z840 Workstation User Manual

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Technical white paper | HP Z840 Workstation
I/O slot options
The HP Z840 provides a total of up to seven high-performance graphics and I/O slots, including support for up to three
PCIe 3.0 graphics cards in PCIe 3.0 x16 slots. In a single-CPU conguration, slot 5 is connected to the chipset at PCIe 2.0
speed with four lanes. A PCIe mux allows a second CPU to connect directly to slot 5, increasing performance to PCIe
3.0 with eight lanes. With the standard 850 W power supply, certain system congurations can support graphics cards
totaling up to 150 W. With the optional 1125 W supply, certain congurations can support graphics cards totaling up to
600 W. In single processor congurations, slot 3 and 4 are not available.
Figure 3. PCIe Single Processor slot layout Figure 4. PCIe Dual Processor slot layout
Recipe for optimizing PCI-Express I/O performance
For high I/O bandwidth applications, the choice of slot loading, CPU, and memory conguration can be optimized to
ensure maximum bandwidth available. Applications and cards sensitive to I/O latency may benet as well from some of
the tips below.
Recommended conguration steps
1. Place GPU and graphics cards rst, following the slot order listed in Table 3.
2. Place I/O cards next, from highest bandwidth to lowest, following the slot order listed in Table 3. This is the optimal
load order for most applications.
3. If the onboard SAS controller is not used and there is an I/O card in slot 1, then disable the SAS controller (BIOS setup
menu -> Advanced -> Device Congurations -> SAS Controller = Disable).
4. For single CPU conguration only, if PCIe 2.0 I/O cards fail to train at full Gen2 speeds (5 Gb/s) in Gen3 slots, then try
slot 5 which only trains up to PCIe Gen2.
5. Additional I/O bandwidth renements may be possible. If necessary, refer to the tips below.
PCIe3x4
PCIe3x16
Not available
Not available
Slot 1
Slot 2
Slot 3
Slot 4
Slot 5
Slot 6
Slot 7
PCIe3x16
PCIe2x4
PCIe2x1
PCIe3x4
PCIe3x16
PCIe3x8
PCIe3x16
Slot 1
Slot 2
Slot 3
Slot 4
Slot 5
Slot 6
Slot 7
PCIe3x16
PCIe3x8
PCIe2x1
c612 PCH Connected CPU0 Connected CPU1 Connected

HP Z840 Workstation Specifications

General

Brand	HP
Model	Z840 Workstation
Category	Desktop
Language	English