I have to admit that I get a little excited whenever a new generation of scorch-your-eyebrows-off CPUs hits the server market. So when I got a chance to check out the newest Intel Nehalem Xeon systems, I made sure my insurance policy was up to date and relocated any breakables to another room.

Intel's newest server processors represent a major architectural change from earlier Xeon generations. One big improvement over previous-generation Xeons is the addition of an onboard memory controller and Non-Uniform Memory Access (NUMA). Taking a cue from AMD, Intel added NUMA to Nehalem to help eliminate cache starvation by tying banks of RAM to each processor.

[ Learn why Intel's Nehalem Xeon processor simply sizzles. Read the InfoWorld Test Center reviews of Nehalem-based Sun Fire servers, Nehalem-based Dell, HP, and Lenovo workstations and the Nehalem-based Apple Xserve and Mac Pro. ]

Intel also redesigned the I/O system between CPU and peripherals, doing away with the front-side bus bottleneck and replacing it with a high-speed pathway called QPI (Quick Path Interconnect). QPI can transfer data to local peripherals as fast as 25.6GBps, nearly double the performance of a 1,600MHz front-side bus system.

Other improvements include the reintegration of Hyper-Threading, the elimination of the Northbridge controller (PCI Express and Direct Media Interface are now in the CPU), and support for DDR3 memory.

Enter the dragon
I was able to secure three tower servers based on Intel's latest Xeon offering from Dell, Fujitsu, and Hewlett-Packard, and from the moment I fired each one up for the first time, I knew these servers were something special. The best part was watching Windows Server 2008 (my requested operating system) boot up in about 52 seconds -- simply fantastic.

In order to make this an apples-to-apples comparison, I requested a similar configuration from all three server vendors. (IBM was also invited, but did not provide a system.) Each server came with two Xeon X5550 2.66GHz CPUs, 24GB of 1,333MHz DDR3 RAM, and Windows Server 2008 Standard Edition (64-bit). I asked each vendor to supply hard drives in a RAID 5 configuration but left the size and type of drives up to each vendor. Dual Gigabit Ethernet and multiple USB 2.0 ports were standard on each system.

To get a feel for each platform's performance, I ran the SPECjbb2005 Java server benchmark and the STREAM memory benchmark tools on each system. The SPECjbb2005 test is a Java virtual machine stress test that emulates a three-tier client/server order and inventory system. During the test, a number of virtual warehouses is created (two warehouses per processor core), with each warehouse handling order entry, payment, status, delivery, and reporting transactions. Additionally, SPECjbb2005 also measures the performance of the CPUs, caches, memory, and the scalability of shared memory.

Rock around the clock
Using SPECjbb2005, I was able to make all 16 cores (8 Hyper-Threaded cores) busy, achieving near 100 percent utilization at the end of the test run. The test suite increased the workload by one until it reached the maximum of 32 virtual warehouses (2 warehouses per core). At the end of the test run, SPECjbb2005 generates a score in bops (business operations per second, and SPECjbb2005's unit of measure) for each warehouse simulation. Bops represent the overall throughput achieved by all the warehouses in a test run; a higher bops value indicates better overall performance.

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