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Citrix Xen Virtual Machine performance better on r210's than r610's, why?


I work for a company that has makes a voice communication platform running on Virtual Machines that are sitting on Dell r210's and r610's. The 210's are outperforming the 610's by over 2 times application response speed. So I started comparing the two CPU's, the x3430 is outperforming the x5650 and I have a hard time understanding why. From testing I have done in the Lab, my results show the x3430 as a better option.

Do you know if DMI bus types are better suited for Virtual Machines instead of QPI bus?

Is Intel Virtualization Technology for Directed I/O (VT-d) a better suited choice since the x5650 doesn't appear to have this feature?

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Software and workloads used in performance tests may have been optimized for performance only on Intel microprocessors. Performance tests, such as SYSmark and MobileMark, are measured using specific computer systems, components, software, operations and functions. Any change to any of those factors may cause the results to vary. You should consult other information and performance tests to assist you in fully evaluating your contemplated purchases, including the performance of that product when combined with other products.

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Hi mrousseau,

Without knowing all of the details around the software product and what features that are incorporated it's difficult to provide a definitive answer. However, Intel VT-d does, in general, provide a boost to performance of virtualized devices connected to the chipset. So, if the virtualization software that you are using supports virtualizing the communication hardware using Intel VT-d and is configured as such on the r210 systems that you are using then it's a good chance this is why you are seeing the performance difference. Without Intel VT-d, software is limited to using software emulation of the hardware and the performance of the device will (in most cases) be significantly lower.

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