Sun's W2100z Dual Opteron Workstation

Components

The simplest way to detail the Sun w2100z is to just open it up and look at what Sun put under the hood. Our side panel on the workstation actually provides us with detailed knowledge of how the system works. You can see the side panel reference below.

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The core of the Sun w2100z is its K85AE motherboard. The K85AE is wildly different from anything to which we are accustomed, even when looking at server motherboards. Sun's modular approach to component design makes it a lot easier to upgrade (providing you use Sun components) and in turn, gives Sun customers a uniform base of components to pick and choose. Our particular w2100z came with all of the options, so we can detail them here.

Sun K85AE Specifications
CPU Type	(2) AMD Socket 940*
Memory Banks	(4) 1GB PC-3200 ECC DDR*
HyperTransport Tunnel	AMD 8111
AGP Tunnel	None
PCI Tunnel	AMD 8131
SATA	Silicon Image Sil3512
PCI Slots	(1) 133MHz PCI-X (1) 100MHz PCI-X
SATA Ports	(2) U150
PATA	(2) ATA100
Audio	Realtek ALC655 AC'97
Network	Broadcom BCM5703 Gigabit Ethernet
Firewire Ports	(2)
USB 2.0 Ports	(2)

You'll notice the star next to the CPU type and Memory banks. The K85AE is a single CPU motherboard with a "CPU mezzanine" - two risers (one for power, one for IO) rise up through the center of the motherboard to provide four additional DDR banks and one additional CPU slot. Sun only needs to produce a single motherboard design and significant space inside the motherboard is saved. The idea of a CPU mezzanine is not new - particularly for Sun - but seeing such technology up close is always exciting. Below, you can see the CPU mezzanine removed from the system (a high resolution reverse side image can be found here.

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There isn't anything too interesting about the mezzanine itself. Sun somewhat exploits the design of Opteron by placing the memory on the mezzanine with the CPU. Remember, all Athlon 64 and Opteron processors have their own memory controllers - each processor has its own memory bank. Technically, the primary Opteron on the motherboard can utilize the memory on the mezzanine via the HTCN bridge, although there is a performance hit by doing so.

The CPU mezzanine sits directly on top of the AMD 8111 HyperTransport hub and the first AMD 8131 PCI-X tunnel. Removing the mezzanine also reveals the Broadcom gigabit Ethernet controller, BIOS and SATA controller. You can read more about the SI controller here, and more about the Broadcom controller here. Both devices have fairly strong Linux support as we will see later in our analysis. The fact that our SATA controller only supports two drives is not of huge significance, since the chassis can only hold two drives anyway. Below is an image of both controllers once the CPU mezzanine is removed. The AMD 8131 is covered by an aluminum heatsink.

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The entire board layout without the extender card can be seen below (those interested in a high resolution reverse side image can get that here:

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The K85AE mainboard is far from legacy free. When we first unpackaged the workstation, we were surprised to not see any PS/2 interfaces (the included keyboard and mouse are USB). Under closer inspection, we noticed that PS/2 connectors did in fact exist, but they were covered by the EMI shield from the case. The motherboard houses two serial connectors and one parallel connector as well.

Also note the 133MHz PCI-X connector (black). The majority of peripheral components on the mainboard are very basic including the Realtek AC'97 audio controller. Sun seems very shy on USB, including only five devices (two of which must be used for the keyboard and mouse unless the PS/2 ports are revealed).