Both Intel and AMD provide a wide range of processors that are appropriate for host servers. The industry competition between the two is very tight and at any one time; one may have a performance advantage over the other. Regardless of which manufacturer is chosen, several performance characteristics are important.
The number of processor cores is a key performance characteristic. Windows Server 2008 R2 with Hyper-V makes excellent use of multi-core processors, so the more cores the better. Another important characteristic is the processor clock speed, which is the speed at which all cores in the processor will operate. It‘s important because it will be the clock speed of all of the guest virtual machines. This is a key variable in the consolidation ratio because it impacts the amount of candidates that the host server can handle AND the speed at which those guests will operate. As an example, choosing 2 GHz processor rather than a 3 GHz processor on a server that will host 20 guests means that all of those guests will run only at 2 GHz.
At a lower level of detail, the server processor architectures make design choices in terms of the type and quantity of processor cache, memory controller architecture, and bus/transport architecture. A detailed analysis of these factors is beyond the scope of this document.
x64 processor architectures are required for all Hyper-V host server architecture. If you are purchasing new servers, we recommend working with your server vendor to ensure that the selected hardware is capable of running Windows Server 2008 R2 and Hyper-V, and that it is validated for Windows Server 2008 R2 failover clustering. For new servers, we recommend selecting the maximum number of cores per processor available and choosing the fastest or second fastest clock speed available.
Memory Architecture Once the system architecture and processor architecture choices are made, there
are relatively few options remaining for memory architecture because it is usually predetermined by the manufacturer/system/processor combination. The memory architecture choices that remain are typically quantity, speed, and latency. For Hyper-V, the most important memory architecture choice is the quantity of RAM. Most consolidated workloads (that is, individual guest virtual machines) will require at least 512 MB to 1 GB of RAM or more. Since most commodity four-socket servers can only cost effectively support between 32 and 128 GB of RAM, this is frequently the limiting factor in host server capacity.
The quantity of RAM is a more important factor than RAM speed or latency.