The Next Generation of Small–Form Factor (SFF) Workstations

Herrera on Hardware: Intel releases Skylake processors, triggering the launch of a new round of workstations — including boundary-bending SFF models.

When it comes to the hardware foundation for visual computing applications such as CAD, three suppliers dominate the landscape: Intel, Nvidia, and AMD. The latter two provide accelerated rendering in the form of high-performance graphics processing units (GPUs) — a critical component in the visual computing equation. However, today, it's the products delivered by Intel — namely, processors — that set the pace for successive generations of workstation products.

With the company now virtually the sole supplier of microprocessors (and supporting silicon, including I/O chipsets), it is Intel's schedule of product launches that dictates the rollout of new workstation products from vendors such as HP, Dell, and Lenovo. For two years, the product landscape has been dominated by Intel's Haswell-generation platform, but that's changing with Intel’s new Skylake generation of products. Workstation vendors are following the launch with a range of Skylake-based products, including new models and refreshed versions of existing models. Small in physical size, the small–form factor (SFF) workstation has developed a major market presence of late, and vendors are seizing on the Skylake product cycle to introduce new models to cash in.

What Does Skylake Bring to the CAD Workstation Party?

Let's take a brief look at Skylake, and how it surpasses the Haswell generation in what it offers CAD workstation applications. The first round of Skylake processors primarily includes models that combine four CPUs (quad-core) and an improved integrated GPU. The combination is particularly appealing for mobile and entry-level deskside workstations, because the integrated GPU option provides value both in reduced cost (in desksides, especially SFF models) and in low-power graphics for periods of low-demand computing (in mobiles).


Quad-core Skylake processors follow the same basic block diagram as recent microarchitecture generations. Image courtesy of Intel.


At a high level, Skylake's improvements on Haswell come from the combination of a higher-performance core microarchitecture and more capable GPU (labeled GT 2/3/4 in the above diagram), supported by more internal cache and faster memory access with support for DDR4 technology. (For some background on the benefits of DDR4 over the previous DDR3 technology, check out this previous Herrera on Hardware installment.)

What do Intel's design improvements yield? Well, Intel is promising a boost of as much as 20% in throughput for its CPU core, as compared to Haswell. As far as GPU performance, this first round of Skylake processors — including the Core i7-6000 and Xeon E3-1200 v5 series — does not take advantage of the additional scaling capabilities of Intel's Gen9 architecture. Rather, Skylake's GT2 GPU (branded HD 530) offers only slightly better performance than Haswell's GT2 GPU (branded HD P4600). Therefore, while some CAD users with very modest visual demands — 2D or simple 3D models — can consider relying on Skylake graphics, as they may have with Haswell, the vast majority will continue to configure workstations with higher-performance, discrete, professional GPUs from NVIDIA (Quadro) and AMD (FirePro).

Dell and HP Improve on the Tried-and-True SFF Workstation

Two of the largest workstation vendors, HP and Dell, were quick to jump on the Skylake train, delivering several new workstation products, including refreshed versions of their entry-class, small–form factor (SFF) workstation models. First introduced by HP in 2009, the SFF workstation dramatically shrinks the footprint of the traditional tower or minitower chassis, so it takes up less space under or on top of the user’s desk. In the past six years, the SFF workstation has been the fastest-growing machine type, now accounting for roughly 40% of all entry-class deskside workstations shipped (source: Jon Peddie Research).

As expected, both HP and Dell used the Skylake cycle to upgrade their respective entry-class deskside models, including tower and SFF versions. Dell replaced its Precision T1700 with the Precision 3000 (tower and SFF) series; HP replaced its Z230 with the new Z240. With the Z240, HP extended support for its Z Turbo PCI Express–based solid-state drive (SSD) down to its entry-level deskside offering. (For more on the benefits that the emerging PCI Express SSDs have over conventional SATA SSDs, check out this previous Herrera on Hardware installment.) Even more appealing for the SFF's tight quarters, this G2 version of the Z Turbo option leverages an M.2 slot, allowing HP to free up a PCI Express slot that the first-generation Z Turbo required. HP also made incremental improvements in air-cooling efficiency, both by improving flow through the chassis as well as making available a novel dust filter to avoid clogging air intakes.


HP's new SFF/tower Z240 workstations (left), alongside Dell's comparable Precision 3000 machines (right). Images courtesy of HP and Dell.


Dell's revamped Precision 3000 minitower touts some similar specifications to HP's Z240 — for example, also introducing an M.2 form factor PCI Express — but it reflects a somewhat different take by the two vendors on design priorities. Whereas HP leaned more toward capacity and features in its 15.1" x 3.95" x 13.3" chassis, Dell opted for minimal size, delivering its hardware in a smaller 11.4” x 3.65” x 11.5” package.

It's worth noting that I use the new SFF machines from HP and Dell as examples of the incremental improvements being made from generation to generation because they are the first Skylake models to be officially unveiled. I expect that forthcoming machines from Lenovo, Fujitsu, and a host of smaller vendors will show similar levels of enhancements over their Haswell-based predecessors.

Boxx Takes a Novel Approach for Maximum SFF Performance

There must be a catch here, right? A smaller workstation sounds better than a big one, so why would anyone design or buy a big model? Well remember that virtually every choice in designing computers comes with a tradeoff; in this case, if you make the chassis smaller, you will need to make compromises in other areas. The most obvious sacrifice is in physical capacity — with a smaller volume available, there's simply not as much space to stuff in components. The most glaring limitation compared to a full-size tower is in storage capacity, but constraints in processors and memory can also be noticeable. That's precisely what we see in the subtle differences between HP's Z240 and Dell's Precision 300 SFF models.

But while available real estate limits what can fit inside an SFF workstation, the chassis's limits on thermal dissipation often impose the more challenging constraints. Positioning heat-generating components in such close proximity creates a higher thermal density (i.e. more heat per cubic inch), a situation exacerbated by the fact that it's more difficult to dissipate that heat through conventional airflow techniques. It's as much the thermal constraints as size that limit the choice of GPU in an SFF workstation as compared to a tower model, for example. Where the SFF versions from HP and Dell top out with an Nvidia Quadro K1200 GPU — an entry-to-midrange card — the full tower version of the same model can accommodate a high-end Quadro M5000, if the user so desires.

However, where there are tradeoffs, there is also opportunity. And in the case of SFF machines, workstation provider Boxx found one. As mentioned, there's an upper limit as to what can be accomplished in the thermal envelope of an SFF chassis as a function of airflow. But who says you have to cool with air alone? Not Boxx, which created the Apexx 1 workstation, a machine that employs liquid cooling to push those thermal limits.

Liquid-cooling technology is typically employed in high-end gaming machines, where it supports overclocking of the CPU, lending players a competitive edge. However, the SFF workstation is an equally compelling application of a liquid-cooling system; it overcomes the tight thermal constraints imposed by the cramped chassis, hot chips, and limited airflow. As with most liquid-cooled approaches, liquid is pumped into a water block mounted on top of the CPU, where heat is conducted from chip to liquid. That liquid circulates out to a radiator positioned at a chassis air exhaust vent. Boxx adds a massive turbine inside that sucks air in and blows cool air through the radiator and out of the chassis.


Boxx liquid-cools its SFF Apexx 1 to ease the platform's thermal constraints. Images courtesy of Boxx.


With the benefit of liquid-cooling, Boxx didn't need to leverage Skylake to achieve performance gains. Rather, Boxx stuck with a previous-generation 8-core Haswell Core i7 CPU, but overclocked the processor to 4.0 Ghz, achieving an impressive level of compact performance. Boxx achieves a higher level of raw performance in a package that’s signficantly smaller than the HP and Dell models discussed above. Of course, Boxx didn't get away with no tradeoffs either — nobody does! — and as you might guess, the tradeoff here is price. While the new SFF workstations from Dell and HP start at $679 and $879, respectively, the least expensive Apexx 1 configuration we could come up with on Boxx's site was $3,525.

Diverse Approaches to Design Challenges

There are two traits, above all, that make the workstation industry a vital, vibrant one, both today and for the foreseeable future. One, the market it serves — high-demand visual computing professionals — value and benefit from each incremental improvement in performance, capability, and reliability. The same cannot be said for the broader consumer and corporate PC markets, where an increasing percentage of users have achieved a "good enough" level in computing. And two, it remains a hotbed for much of the creativity and innovation we see in performance-oriented computing.

The vast majority of CAD professionals haven't hit satisfaction levels anywhere near "good-enough" computing, and they won't anytime soon. Investments in new generations of technology and products continue to provide substantial concrete returns in productivity, and through gains in productivity, directly contribute to a business's bottom line. Serving the hungriest of computing consumers, the workstation industry inspires anything but me-too products, as the creation and evolution of the SFF machine is showing. The platform continues to push forward in performance and capabilities, be it on the back of cost-conscious design enhancements and component-level improvements like the introduction of Skylake — as Dell and HP have done — or through a twist on the platform designed to squeeze every last drop of performance from the machine, as Boxx delivers with the Apexx 1.