Ten blades fit into a single Dell chassis, resulting in a single rack density of 60 dual-socket systems. With the soon-to-be-released quad-core Intel chips, this equates to 240 cores per rack, with a maximum power draw of 3.6 kW.

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Each blade sports two 2.5-inch SAS or SATA hot-swap drives with hardware RAID0/1, expanding up to 32GB of DDR2 RAM and dual or quad-core CPUs. The external I/O layout is similar to the HP solution, with integrated switching across a passive midplane and either an integrated Cisco 3030 or a Dell PowerConnect 5316M gigabit blade switch module. Straight gigabit Ethernet pass-through modules are available, as well.

On the FC (Fibre Channel) side of the aisle, you have both McData and Brocade 4GB FC switch modules available, as well as a pass-through module. The PowerEdge 1955 handles InfiniBand with a Topspin pass-through module providing a single port per blade.

In the lab, our PowerEdge 1955 chassis sported a PowerConnect 5316M switch, which is accessible at the console level via the chassis management tool's CLI. Of the 16 ports on the switch, 10 are reserved for blades at one port per blade, and the other six are broken out into RJ45 ports on the back of the module.

We successfully trunked this module to a Cisco 4948-10G switch to provide 6Gb of throughput to the main lab network. It would be nice to see 10 Gigabit Ethernet support in this chassis, but then, none of the blade systems we evaluated could do 10 Gig — yet.

Access made easy
One of the Dell system's unique features is the integrated KVM switch. It's a Dell-branded Avocent switch that has internal connections to each blade, and breaks out into a standard PS/2 and VGA port via a dongle on the back of the chassis. This permits quick and easy direct KVM access to each blade, and can uplink to another KVM switch relatively easily.

Further, this same KVM module doubles as an Avocent digital KVM port, permitting instant integration into another Avocent/Dell KVM switch to make management even easier. Each blade also has a front-mounted dongle connector that can support a directly connected monitor and keyboard. It's the best direct (non-IP) console management of any blade system.

The PowerEdge 1955 Blade System would be quite at home in a standard datacenter running a single server per blade, in an HPC environment serving as a low-footprint collection of compute nodes, or in a virtualization scenario (the Intel VT extensions are available, but disabled by default). In fact, when VMware Virtual Infrastructure Server 3 was evaluated in the lab, VMware engineers chose to use the Dell chassis to run all their tests — partly because the Sun Blade 8000 system was still in use re-running the SPEChpc tests, but also because they were sure that there were no compatibility issues with the Dell blade system, and it had the performance levels they needed.