The six-core Opteron is not an alternative to the mighty Xeons in every application. The Xeons are more versatile thanks to the higher clockspeeds, higher IPC, Hyperthreading and higher bandwidth to memory. The Xeon 55xx series is clearly the better choice in OLTP, ERP, webserving, rendering and there is little doubt that it will continue to reign in the bandwidth intensive HPC workloads. There are two types of applications where we feel that the AMD six-core deserves your attention: decision support databases and virtualization.
Since the launch of ESX 3.5, VMware has said more than once that performance-critical applications such as OLTP and Decision Support Databases will perform well on top of their hypervisor. Several enhancements make the newly launched vSphere 4 an even more attractive platform for such "heavy duty" applications. Hyper-V R2 and Xen 3.4 are clearly gearing up for the same task. So it is interesting that companies are now looking into virtualizing those performance-critical applications, the applications that still got their own dedicated server a few months ago. The motivation is that virtualizing these applications would allow the complete datacenter to be managed with the same flexibility as the light, already consolidated, applications. VMotion (Xenmotion, Live Migration) can then for example be used to migrate these applications faster and much more easily.
Of course, performance-critical applications are by definition more demanding when it comes to processing power. That is exactly what vApus Mark I measures: how well do performance-critical applications perform when they are virtualized? This is a relatively “new” market where the AMD 2435 shines. The new Opteron 2435 at 2.6 GHz was a pleasant surprise on vApus Mark I: it keeps up with more expensive Xeons on ESX 3.5 update 4 while consuming less, and offers a competitive performance/watt and performance/price ratio on vSphere 4. The six-core Opteron is about 11 to 30% slower on vSphere 4 than the 2.93 GHz Xeon X5570 but the overall cost of the Istanbul platform is significantly lower (DDR-2 versus DDR-3) and the 2.6 GHz 2435 consumes less power in a virtualized environment (*). On the condition that you optimize your hypervisor well to take advantage of the six cores (cell size is for example one critical optimization), we feel that the six-core Opteron is a worthy opponent for the Xeon “Nehalem” in this market. We tested only the 2435 versus the X55xx series. The Xeon E5540 2.53 GHz versus the Opteron 2431 2.4 GHz may show a slightly different view… the six-core Opteron and Xeon are both very competitive in this area, other factors than performance/price/power might conclude the decision. There is no clear winner in this part of the market, but the big news is of course that AMD offers a worthy alternative.
VMmark tells us that the Xeon X55xx handles large amounts of VM’s much better. With “light VM’s” the amount of memory you can place in a server plays in many cases a more important role than the CPU. In that case you might be better off with a low power quad-core instead of a six-core or high-clocked quad-core.
Lastly, the six-core Opteron will be a formidable competitor in the 4P market segment. But that is for a later article.