Back in December 2009, I reviewed three of the newest Intel Nehalem Xeon-based servers from Dell, Fujitsu, and HP and found that the Xeon X5500-series CPU provided substantial performance gains over all other server CPUs on the market. The Xeon's new architecture, QuickPath Interconnect, and on-die memory controller put the Nehalem at the top of the server food chain.
A year later I find myself staring at a Dell PowerEdge R715 chassis outfitted with a pair of the latest and greatest AMD Magny-Cours Opteron processors, and I wonder if the Opteron's performance can take the top spot away from Intel. My 2U rack-mount chassis is a work of engineering art, and it's not just because of the dual Opteron 6174s stuffed in the box. From the excellent performance to the large amount of system RAM to the densely packed storage using 2.5-inch drives, the R715 is a great platform to build any data center around.
Magny-Cours: Not your papa's Opteron
The heart of the Dell PowerEdge R715 is the new Opteron 6000-series CPU, which is a major departure from previous Opteron processors. The 6000 series comes with either 8 or 12 physical cores on the die, 128K L1 and 512K L2 cache per core, and 12MB of shared L3 cache. Clock speeds range from 1.8GHz to 2.3GHz. (For comparison, the latest Intel Xeon 5600-series processors have up to 6 physical cores, or 12 threads with Hyper-Threading enabled, also with 12MB L3 cache and clock speeds up to 3.33GHz.) In addition to the two 12-core 2.2GHz Opteron 6174s, my test system included 32GB of DDR3 RAM, three 146GB 15,000 RPM SAS hard drives, dual hot-swap power supplies, and a four-port copper Gigabit Ethernet adapter. The new Opteron requires a much larger socket, the LGA1944, instead of the smaller LGA1207 Socket F.
Other improvements are HyperTransport 3 (HT3), support for 1,333MHz of DDR3 RAM, quad-channel memory, and AMD-V (AMD Virtualization). HT3 is the communication path between processors and I/O, much like Intel's QuickPath Interconnect. HT3 ups the interconnect rate from HyperTransport 2's 2.8GT/s to 6.4GT/s (that's gigatransfers per second) -- also the speed found in Intel's QuickPath.
Previous Opterons worked only with 800MHz DDR2 memory. This generation supports DDR3 memory up to 1,333MHz. Not only that, the Opteron 6000 series doubles the memory capacity per CPU by way of quad-channel memory, which is especially beneficial for RAM-intensive applications such as databases or application servers.
One new feature that will have an immediate impact on IT shops that run a virtualized environment is AMD-V 2.0. AMD-V is a set of technologies baked into the CPU that are designed to improve virtual server performance and help IT make better use of its server hardware investment. One of the most important is I/O virtualization. This allows a virtual machine to communicate directly with system devices, bypassing the hypervisor for improved performance.
Benchmarking the Dell PowerEdge R715
As I did with the previous Nehalem servers, I tested the Dell PowerEdge R715 using the SPECjbb2005 Java server benchmark and the STREAM 5.8 memory benchmark tools. It turns out the performance of the latest Opteron is fantastic, outpacing my Xeon X5550's by 40 percent, despite the Opteron running at a slower clock speed: 2.2GHz vs. 2.67GHz for my X5550. In the SPECjbb2005 test, the Opteron produced a per-Java-virtual-machine score of 140,667 bops (business operations per second), while the Xeon X5550 chassis turned in a more modest 75,514 bops.
SPECjbb2005 emulates a three-tier order and inventory application. It creates two warehouses per processor core, each warehouse handling order entry, payment, status, delivery, and reporting transactions. It's a good measure of the performance of the JVM, CPUs, caches, and the scalability of shared memory processing. (Note: I used the Oracle JVM for this round of tests and retested my Xeon reference chassis to keep results as apples-to-apples as possible.)
Keep in mind that the R715 has three times as many physical cores as two Nehalem Xeons, so the extra power usage isn't surprising. With the large number of cores in the chassis and virtual machines that the R715 can accommodate, it's easy to see that IT will be able to recoup any additional power costs by eliminating extra chassis from the data center.
Inside the Dell PowerEdge R715
Whenever I get a new server on the bench, one of the first things I do is pop the top to have a look inside. With the R715, I was not surprised to find a well-designed chassis. The roomy 2U is nearly 100 percent tool-less, providing quick and easy access to all of the major system components. A bank of six hot-swappable fans in the middle of the chassis pulls cool air in from the front, and a large flat shroud directs air over the CPUs and 16 DIMM slots. The R715 supports dual CPUs up to and including the 2.3GHz Opteron 6176SE and can handle a maximum of 256GB of RAM. My test chassis also included two 750W hot-pluggable power supplies (1,100W units are also available).
Hard drive and network interface choices abound with the R715. It can have up to six 2.5-inch SATA, SAS, and SATA SSD (solid-state device) drives and a wide range of network cards from Broadcom and Intel, including various 10GbE adapters and dual- and quad-port GbE. And with six more PCIe slots available for add-on cards, there's plenty of flexibility for future upgrades.
A very useful feature included in the system is Dell's iDRAC6 Express remote management controller. This "system on a chip" helps IT keep up with the health of the server by monitoring critical system components, including fans, power supplies, temperature, CPU, RAM, and hard drives. iDRAC 6 is not dependent on the server to be operational; IT can access the controller even when the server is powered off or crashed. Through iDRAC 6, admins can also apply software and firmware patches. With the Enterprise edition, you can even access a virtual console for remote KVM access to the server.
Dell has done an excellent job of combining AMD's Opteron 6100-series CPUs with a server platform that will meet the needs of businesses everywhere. I was more than impressed with the overall performance of the R715 server, and I always like having many choices for hard drives and expansion cards. The inclusion of the iDRAC 6 Express controller is a nice touch at a price lower than a similarly configured Intel Xeon server. There is much to like here with little downside.