Closer look at the Platform: Intel Celeron 847 CPU + Intel NM70 Chipset
Having experimented with Atom CPUs and found no way to make them stay in compact PCs, Intel turned to Plan B which meant the promotion of CPUs with the premium Core architecture but adapted for low power consumption. Fortunately, the Core is a versatile microarchitecture that can be employed for high-performance and energy-efficient applications alike. The configuration Intel wants to suggest as an alternative to the latest Atom-based platform Cedar Trail consists of highly economical components which are initially designed for mobile solutions. Considering that low pricing has always been a key feature of Atom CPUs, such components are also very inexpensive.
So, the platform positioned by Intel as a basis for SFF PCs is based on the dual-core Celeron 847 processor (or its single-core cousin Celeron 807). There’s nothing particularly new about it as it was introduced as a mobile solution two years ago, yet it’s only recently that Intel has oriented it at nettops and mini-ITX mainboards. It is no wonder then that the Celeron 847 is manufactured on old 32nm tech process and represents the Sandy Bridge design.
The Celeron 847 has a typical TDP of 17 watts but its real heat dissipation must be lower. On the majority of mainboards it is only equipped with a small aluminum cooler with 40mm fan. The low power consumption and heat dissipation are ensured in a brute force way by lowering voltage to about 0.5 volts. The clock rate is very low under such conditions – 1.1 GHz only. We shouldn’t forget that it is a full-featured Sandy Bridge, though. It is a CPU with out-of-order execution, each of its cores capable of crunching through up to four x86 instructions per clock cycle.
Moreover, the Celeron 847 boasts some new features compared to the Atom series including a shared 2MB L3 cache, SSE 4.2 support, and a dual-channel memory controller. The Intel HD Graphics core is fundamentally superior to the Atom’s GMA 3600. It has no problems decoding HD video, supports DirectX 10 and offers higher performance, even though its clock rate is lower than in ordinary Sandy Bridge CPUs (800 MHz in 3D mode and 350 MHz in 2D mode).
Being originally conceived as mobile solutions, Celeron 847 CPUs are manufactured as BGA1023 chips and get soldered to mainboards. As with the Atom, there’s no talking about upgrades, of course.
Intel’s NM70 chipset serves as the Celeron 847’s companion. It is akin to other series 7 chipsets from Intel such as the Intel Z77, but its capabilities are severely limited. The NM70 is closer to the mobile HM70 chipset in specifications and has the same specified TDP of 4.1 watts, but the number of PCI Express lanes and USB ports is reduced, which gives us the following characteristics:
The chipset is connected with the CPU with a standard DMI 2.0 bus that has a bandwidth of 20 Gbps, making the Celeron 847 + NM70 Express pair similar to any other Sandy Bridge or Ivy Bridge platform except for the limited expansion capabilities. Particularly, they do not allow using external graphics cards and only offer four PCI Express lanes for additional controllers.