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Technical white paper | HP Z640 Workstation
I/O slot options
In addition to the 32-bit/33 MHz full height and full length PCI slot, the HP Z640 provides a total of up to five high-
performance graphics and I/O slots in single CPU configuration and up to four high-performance graphics and I/O slots in
Dual CPU configuration, including support for up to two PCIe 3.0 graphics cards in PCIe 3.0 x16 slots. The remaining PCIe
slots are open ended and can accommodate a variety of different cards and configurations.
Figure 3.
I/O slot layout (single CPU configuration)
Figure 4.
I/O slot layout (dual CPU configuration)
Recipe for optimizing PCI-Express I/O performance
For high I/O bandwidth applications, the choice of slot loading, CPU, and memory configuration can be optimized to
ensure maximum bandwidth available. Applications and cards sensitive to I/O latency may benefit as well from some of
the tips below.
Recommended configuration steps
1. Place Graphics and GPU cards first, 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 PCIe 2.0 I/O cards fail to train at full Gen2 speeds (5 Gb/s) in Gen3 slots, then try slot 1 or slot 3 which only trains up
to PCIe Gen2.
4. Additional I/O bandwidth refinements may be possible. If necessary, refer to the tips on following page.
Riser
Connector
PCIe2 x1
PCI32
PCIe2 x4
PCIe3 x8
Open ended, full height, half length
Slot 1
Slot 2
Slot 3
Slot 4
Slot 5
Slot 6
Open ended, full height, full length (with extender)
Open ended, full height, full length (with extender)
PCIe3 x16
PCIe3 x16
Retention latch, full height, full length
(with extender)
Retention latch, full height, full length
(with extender)
32-bit/33 MHz, full height, full length (with extender)
CPU0
PCIe2 x 1
PCI32
PCIe2 x4
PCIe3 x8
Slot 1
Slot 2
Slot 3
Slot 4
Slot 5
Slot 6
Open ended, full height, full length (with extender)
Open ended, full height, full length (with extender)
PCIe3 x16
PCIe3 x16
Retention latch, full height, full length
(with extender)
Retention latch, full height, full length
(with extender)
32-bit/33 MHz, full height, full length (with extender)
CPU0
Riser
Connector
CPU1
Slot 1
