Thanks to a new breed of microprocessors from Intel and AMD, thin is in, with more power than previously available in the familiar 1U rack-mountable pizza box format. Recently, Dell upped the ante by using new, Nocona-series Intel Xeon processors in its PowerEdge 1850 server - its best 1U server ever.

Blade server pioneer RLX has also just launched two 1U blades, the RM1100 and the RM1400, both of which support Xeon EM64T processors.

HP is nipping at Dell's heels, however, offering solid feature upgrades and new Xeon processors in the fourth generation of its flagship 1U model, the ProLiant DL360 G4.

The move to Nocona is evolutionary, not revolutionary, yet the base-level specs of the system - dual 3.4GHz Xeon processors, each with 1MB of L2 cache and an 800MHz front-side bus - are nothing to sneeze at. This is a significant improvement over the G3 version of the server, which had dual 2.4GHz Xeons and a 533MHz front-side bus. It's worth noting that both HP and Dell are currently topping out their offerings with 3.6GHz Xeons.

What do you get with Nocona-based servers, beyond the faster clock and bus? You get Intel's EM64T, a set of 64-bit extensions to the 32-bit x86 instruction set, modelled on AMD's Opteron and its AMD64 extensions. Microsoft isn't yet shipping a version of Windows Server 2003 that takes advantage of the 64-bit extensions, but HP supports 64-bit Red Hat (Profile, Products, Articles) and SuSE Linux, which do use those extensions. I received a 32-bit Windows Server 2003 system for review, so I wasn't able to evaluate 64-bit performance.

The DL360 G4 also includes support for PCI Express, a faster bus than traditional PCI-X. To use PCI Express, you have to physically change a riser card on the server backplane to have the correct connectors. Both Dell and HP offer dual slots, but Dell requires that they both be the same, that is, all PCI Express or all PCI-X. With HP, you can mix and match PCI Express or PCI-X, although the review system only had PCI-X slots.

New and improved
On the high-availability front, the DL360 G4, like the DL360 G3 and Dell PowerEdge 1850, has hot-swap power. New for the G4 is redundant, hot-swappable cooling, placing it on par with Dell.

Also new is online spare memory, which is a BIOS-configurable option; if a chip goes bad, the server can swap in a new one without failure and continue to run until the machine can be serviced.

As for storage, the DL360 G4 server remains configured for two Ultra320 SCSI or SATA drives, but HP improved the onboard RAID controller. The new Smart Array 6i handles 320MB per second per channel, thanks to its 64-bit 133MHz bus connection; the G3's Smart Array 5i Plus was limited to 160MB per second per channel. (The PowerEdge 1850 offers several optional RAID controllers, some at 160MB per second, others at 320MB per second.)

On the physical side, HP does a better job on ergonomics and physical form-factor than Dell. The DL360 G4 is 27 inches deep and has easily accessible ports on the back. The PowerEdge 1850 is 30 inches deep, and its ports are hard to work with, due to an overhang needed to accommodate its expansion slots.

HP also installed three USB ports, two on the outside (which can be disabled in the BIOS for security purposes), and one inside, hidden under the cover, which is useful when bench-testing the machine to hook up keyboard, mouse, or mass-storage devices.

A final improvement: although the server's built-in iLO (Integrated Lights-Out) management controller remains essentially unchanged, HP has provided yet another BIOS switch. Now, iLO can continue to be accessible by a dedicated 10/100 Ethernet port or can be put onto the same NIC slot as the server's dual Gigabit Ethernet interfaces.

Companies that run a separate management network will want to keep iLO separate; those that run iLO on the production network (as I do) can simplify cabling and save a switch port by running it with the GbE ports. In either case, iLO maintains its separate IP address and still functions even when the main processors are offline.

Who's on first?
In effect, the DL360 G4 and PowerEdge 1850 specs are identical, because they both use the same processors and chip set (the Intel E7520). I give HP a slight nod, due to its onboard spare memory and better ergonomics. In reality, were I deploying the servers, I'd probably buy whichever was cheaper.

Nevertheless, it's clear this generation of thin server is more enterprise-class than its predecessors. In the case of the HP box, the redundant cooling, onboard spare memory, and improved RAID controller brings the system up to par with the company's larger 2U servers; the only real difference is that the DL360 G4 has only two internal drives and two slots whereas many larger servers have more of both.

The usual differentiation between 1U and 2U servers - the lack of high-available components - has finally disappeared. Unless you have other specific requirements, save money: go with 1U.