Today, Intel unveiled a new range of Xeon brand processors. The new processors, which Intel awkwardly calls "the Intel Xeon processor D product family," henceforth referred to as Xeon D, are a series of system-on-chip server processors intended for blade and high density server systems.

While Intel is broadly dominant in the server and datacenter market, the growing threat of low power, high density server processors—probably using the ARM instruction set—continues to grow. ARM-based servers aren't a big thing yet, but it wasn't so very long ago that the same was true of ARM-based computers. That all changed with the rise of tablets, Chromebooks, and even micro-computers such as the Raspberry Pi. The same could happen in the server room, and Intel wants to be ready.

Intel is starting with two Xeon D processors; an 8-core, 16-thread part with 12MB cache and a 2GHz base/2.6GHz turbo clock, and a 4-core, 8-thread part with 6MB cache and a 2.2GHz/2.6GHz turbo clock. The cores use the latest Broadwell architecture, built on Intel's 14nm process. Aside from those core count, cache, and clock speed differences, the processors are the same: two memory channels supporting DDR3 and DDR4, for a total of up to 128GB RAM, 24 lanes of PCIe 3, eight lanes of PCIe 2, two 10gigE controllers, six SATA 3 channels, four USB 3 and four USB 2 ports, all with a power rating of 45W.

The processor cores, memory controllers, and high-speed I/O (Ethernet and PCIe 3) are all on the same die. The slow I/O (USB, PCIe 2, SATA) that would traditionally be in an external south bridge chip are on a separate die housed within the same chip package.

As well as packing in a bunch of processing power and connectivity, the processors include a range of power management and power saving features in a bid to improve efficiency. These include a power optimized turbo system, wherein the processor tracks whether the boosted clock frequency is actually providing meaningfully increased performance. If it isn't, it'll cut back the power budget assigned to a core and use it elsewhere.

The chip can also autonomously make decisions about which power and sleep state to use, rather than depending on the operating system to control these things. Intel says that this means the system can respond more quickly, and it also enables, for example, an entire rack of systems to be configured with the same power management configuration, independent of the operating systems running in the rack.

As implied by the Xeon name, the Xeon D processors are server-oriented parts, and they come with many server-oriented features. This includes reliability features such as support for ECC memory and PCIe checksumming to ensure data integrity. DDR4 memory also supports checksumming. A feature called asynchronous DRAM refresh improves behavior when system power fails; in systems with suitable battery backup, the processor can force all outstanding writes to be flushed to RAM and then set memory to self-refresh.

They also support PCIe non-transparent bridging (NTB). NTB allows multiple systems to be joined via their PCIe buses. This enables systems to, for example, share PCIe devices, enabling redundant access to those devices.

The big omission, such as it is, is support for multiple processor sockets: the Xeon Ds are strictly for single socket systems, where scaling is achieved through packing lots of single socket systems into a single rack, rather than building one huge multiple socket system. This isn't an issue for Intel's intended market: Web serving, memory caching, storage, and even routing and network security devices.

Intel has various benchmarks showing how fast the Xeon D is. These benchmarks compare the processor against Avoton, its Atom core server-oriented system-on-chip. Compared to Avoton, Xeon D has considerably more I/O—Avoton only had 16 lanes of PCIe 2 and quad 2.5gigE—and more processing power—16 threads on the eight-core part, rather than just eight. In SPECint_rate, a multithreaded test of integer performance, a preproduction Xeon D at 1.9 GHz showed 2.63 times the performance of an Avoton at 2.4GHz. In workloads such as Java and PHP Web serving, the gains are greater still, with the Xeon Ds 3.15 and 3.4 times faster than the Atom part respectively.

This greater performance does come at some cost; the Atom processors draw only 20W of power, compared to the 45W of the Xeon Ds. That still represents greater performance per watt, and the new processors should find some success in their target market.

Is this enough to keep companies from considering ARM? That's harder to say. Intel certainly has things that work in its favor. The Xeon Ds look to be strong offerings from a performance and functionality perspective, and compatibility with the vast body of x86 software is always going to be an Intel advantage.

But there are ARM advantages, especially for large buyers of servers such as Facebook or Google: ARM has many vendors who are willing to customize designs to meet a customer's needs. If a particular customer wants, say, integrated crypto acceleration, or more built-in Ethernet connectivity, or video codec accelerators, ARM vendors can deliver that. AMD, too, wants to make this kind of customization a part of its product range. This kind of customization, however, has never been Intel's forte, with the company instead building its business around massive scale. The chip giant has made inroads of its own into this kind of customization, but at the moment it's still going to be the ARM companies that are best at offering customized, tailored chips.

The first two Xeon D processors are available immediately, costing $199 for the 4-core version and $581 for the 8-core version. Over the course of the year, the company intends to flesh out the line, with variants optimized for different applications such as storage, networking, and Internet-of-Things devices.