Microsoft invites punters to test drive custom Arm-based Cobalt 100 CPU VMs in Azure

Subscribers in US, Europe, SEA can take silicon out for a spin for free

Build Microsoft is bringing its custom-designed Arm-based Cobalt 100 processors closer to the public as it is now demoing the chips in an Azure virtual machine (VM) preview.

The three-strong pre-release VM series, labeled Dpsv6, Dplsv6, and Epsv6, will be available in the US, North and West Europe, and Southeast Asia regions per an invitation from the tech giant. Subscribers to Azure will be able to try the Cobalt 100-powered VMs for free, except for any storage or other resource usage beyond the VM itself, provided they successfully request access to this limited preview.

While all three Cobalt 100 VM variants have access to up to 96 virtual cores, each one offers a different RAM to core ratio, with Dplsv6 VMs getting 2GB per core, Dpsv6 4GB per core, and Epsv6 "up to" 8GB per core. That "up to" is an interesting caveat for the Epsv6 that one should be aware of; instances of this VM type may not get all the memory one expects.

For instance, Redmond says Epsv6 VMs will have up to 672 GB, but the promised memory-to-core ratio of up to 8:1 should mean a max 768 GB. The core topology of the VMs is also not clear, as each Cobalt 100 processor has 128 Arm-designed Neoverse N2 CPU cores, significantly more than the 96 virtual cores each VM has access to. We've reached out to Microsoft for clarification on these points.

Microsoft, by the way, explicitly says these VMs are "for more memory intensive workloads."

Compared to previous Ampere Altra-powered Azure VMs, Microsoft says the new Cobalt 100 variants have 40 percent more CPU performance. Given those Altra chips used Arm's earlier Neoverse N1 cores and TSMC's 7nm process compared to Cobalt 100's latest Neoverse N2 cores and a 5nm node, a significant boost in performance isn't unexpected.

Additionally, the new VMs also come with four times the local storage IOPS and 50 percent more network bandwidth, we're told, which probably factor into Microsoft's claims of 50 percent higher Java performance and double the performance for web servers, .NET applications, and in-memory cache applications despite the base CPU performance being just 40 percent.

Microsoft's Arm-based components certainly have competition ahead in the cloud server market, not just against those using dominant x64 chips made by Intel and AMD, but also those using various rival Arm-compatible processors.

Redmond undoubtedly wants a slice of the overall pie as a newcomer to custom public-facing CPUs. What's amusing is that these Microsoft VMs will pretty much all be running Linux, not Windows, we imagine. ®

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