Sun Microsystems, Inc.
PCI-X and PCI-E Expansion Slots
The PCI slots on the Sun Fire X4600 server use a 3.3 Volt signaling bus. Therefore, they support only 3.3 Volt
keyed expansion cards. The use of 5 Volt keyed expansion cards is unsupported and will result in damage to
the motherboard.
The PCI-X slots accomodate expansion cards which adhere to the MD2 form factor standard. MD2 PCI-X cards
are a maximum length of 169.3 mm (6.7 inches) and a maximun width of 51.5 mm (2.5 inches). The PCI-E
slots accomodate expansion cards which adhere to the low profile form factor standard. Low profile PCI-E
cards are a maximum length of 165.65 mm (6.65 inches) and a maximum width of 69.9 mm (2.731 inches).

Sun Fire X4600 Server PCI Expansion Slots

The Sun Fire X4600 server has eight PCI expansion slots: 2x PCI-X and 6x PCI-E. All eight slots are capable of
32- or 64-bit operation and support PCI or PCI-X and PCI-E expansion slots. The combination of PCI-X and
PCI-E expansion capabilities enables more flexibility to support both legacy PCI/PCI-X connectivity as well as
higher speed next-generation PCI-E interconnetcs for maximum I/O options and throughput.
Figure 3-8: Sun Fire X4600 PCI Expansion Slots
From the rear of the server, the PCI-X slots are located in the leftmost position. The six PCI-E slots are oriented
in two sets of three. While all PCI-E slots are implemented using x8 lane wide slots, there are electrical
difference among the slots in terms of the bandwidth they support. As expected, the two left slots are x8 width,
but the right slots in the trio are electrically x4 lane width. This physical x8 lane slot with x4 lane electrical
connectivity is known as a soft 8 slot.
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