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Monthly Archives: July 2007

Comparing Intel Dual-Core and Quad-Core Using VMmark

I have been running VMmark on a wide variety of systems in preparation for the benchmark’s imminent release. During this exercise, I was able to measure the performance difference between Intel’s dual-core (Woodcrest) and quad-core (Clovertown) processors using otherwise identical HP Proliant DL380G5 systems. One system contained two dual-core Intel Xeon 5150 processors (four cores total) running at 2.66 GHz. The other system contained two quad-core Intel Xeon 5355 processors (eight cores total) running at 2.66 GHz. Each system contained 32GB of memory and was connected to the same VM library hosted on an EMC CX-300 storage array. Both systems were running ESX Server 3.0.1.

The figure below shows the benchmark scores as the number of tiles was increased until CPU saturation was reached for each system. The dual-core system became fully saturated when running three tiles whereas the quad-core system became saturated at five tiles.


The systems achieved nearly identical benchmark scores for one and two tiles. This behavior was expected since neither system had exhausted its CPU resources. At three tiles, the dual core system was fully utilized, which limited the score, while the quad core systems continued to scale well due to the additional available CPU resources. The quad-core system delivered a 28% higher score with three tiles. The quad-core system became saturated at five tiles and ultimately achieved a score 70% higher than the dual-core system while supporting 67% more VMs.

Many people have asked how much additional performance quad-core processors can provide over their dual-core cousins. These results should help to answer that question while demonstrating the value of having a representative benchmark for mixed virtualization workloads.

Performance and scalability of virtualized Microsoft Exchange 2003 on VI 3

Many of our customers have already virtualized Microsoft Exchange 2003 on VMware ESX Server 3.  For customers who are considering virtualizing Exchange and want to know what to expect in terms of performance, we’ve published a whitepaper on the performance of Exchange in a virtual environment: http://www.vmware.com/pdf/Virtualizing_Exchange2003.pdf

The paper presents the results of a joint study with Dell that examined the performance implications of a virtualized Exchange environment. Specifically, we looked at:

  • The performance implications of running Exchange Server 2003 on a virtual machine versus a physical system.
  • The performance of Exchange Server 2003 in virtual machine configurations when “scaling-up” (adding more processors to a machine) and “scaling-out” (adding more machines).

The details of the configurations and results of the above experiments are documented in the white paper.

To briefly summarize, the results from the study indicate that on an Dell PowerEdge 6850 server configured with four 2.66 GHz dual-core Intel Xeon 7020 processors and 16GB of RAM.

  • A uniprocessor virtual machine can support up to 1,300 Heavy Exchange users.
  • Consolidating multiple instances of these uniprocessor Exchange virtual machines can cumulatively support up to 4,000 Heavy users while still providing acceptable performance and scaling.
  • Uniprocessor virtual machines are, from a performance perspective, equivalent to half as many multiprocessor (two virtual processors) virtual machines.