Microsoft added two new instances which are targeted at high performance computing. Instance called A8 has 8 virtual cores with 56 GB of internal memory. Instance A9 has 16 virtual cores with 112 GB of memory.
In addition both A8 and A9 instance have a 40Gbit/s InfiniBand network that includes remote direct memory access (RDMA) technology for maximum efficiency of parallel MPI applications. This powers high performance applications that require a low latency and high throughput communication between compute instances.
Mind the Infiniband connection is only used to connect to other instances. It is not used to connect to Azure Storage.
So both these instances have two network interfaces: one traditional Ethernet and one Infiniband.
This combination of features makes these instances optimal for running compute and network intensive applications such as high performance cluster applications, applications using modeling, simulation and analysis, video encoding etc
These instances are available for the Windows Azure Cloud Services only at the moment. Cloud Services is the Platform as a Service offering of Microsoft Azure in which the customer does not have to worry about management of the operating system layer of the instance.
The A8 and A9 instances are initially available only in US North Central and Europe West
It is expected Microsoft will make A8 and A9 available for Azure Virtual Machines (IaaS model) in the near future.