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April 10, 2009
Atom platform expands, but does it have a clear direction?
In the days of the 386, 486 and even early Pentium processors, it used to be fairly easy to follow Intel's chips as they mainly differed in clock speed. These days, staying on top of Intel's various offerings has become an almost full time job. That even goes for Intel's low-end Atom chips that, together with resurrecting some older Intel technologies such as hyperthreading, seemed to simplify the matter of processor selection. It didn't really turn out that way. Intel has been very successful in positioning the Atom processor as new, exciting, efficient and just generally the way to go, but it's really not that simple.
For example, "Atom" has from the start referred to two very different processor families.
The initial generation of Atom processor was the Z5X0 that was codenamed "Silverthorne" with a tiny 13 x 14 mm package footprint. They were targeted at mobile internet devices (MIDs) and used the also entirely new "Poulsbo" System Controller Hub. The processor has about 47 million transistors, which is more than the Pentium 4 had. Bus frequency is 400 or 533MHz (which support Intel's HyperThreading). Thermal Design Power is between 0.85 watts for a low-end 800MHz version without HyperThreading, and 2.65 watts for a 1.86GHz verison with HyperThreading. The chipset uses about 2.3 watts, which means total CPU and chipset consumption isn't even 5 watts. And the chipset has hardware support for H.264 and other HD decoding. However, as a the combo is targeted for internet devices, there is PATA but no SATA support.
A second family of Atom processors, the N2X0 that was codenamed "Diamondville," was meant for standard low-cost PCs and netbook type of devices. The N2X0 is similar in many ways to the 5XX platform, but used a somewhat larger 22 x 22 mm package. The N270 has a TDP of 2 watts and costs less than US$44, the same speed N230 4 watts and US$29. As of now, the N2X0 processor generally uses a version of the older i945 chipset. In order to reduce its power consumption down to 5.5 watts, its frequency (and performance) have been lowered as well and the chipset is called the i945GSE. This is used in the N270. The N230 chip, geared towards desktops, uses the i945GC that is quicker, but also uses 18 watts! Note that the i945's GMA 950 IGP is not able to decode HD signals. The N2X0 can be used with SiS chipsets. though I haven't seen any such systems.
From the looks of it, system designers have been struggling in figuring out whether to use the Z5xx or the N2xx chip. In netbooks it was a slamdunk for Diamondville as almost all netbooks use the 1.6GHz N270. However, there are exceptions. When Panasonic introduced its Toughbook CF-H1 Mobile Clinical Assistant, it came with the 1.86GHz Atom Z540 processor. And when Samwell, one of Taiwan's major OEMs in the semi-rugged and rugged space, introduced what is essentially a rugged tablet version of a netbook, they also picked a "Silverthorne" processor, in this case the Z530P.
I am not sure what drives the decision to go with a Atom N270 versus a Atom Z530. On the surface, they seem to have about the same performance and use about the same amount of power. One glaring difference in their specification is that the N2XX series supports the ever-important SATA (serial ATA) disk interface whereas the Z5XX does not and needs to use PATA drives. On the other hand, the technically inclined point out that the N2XX's use of a very slow version of the already dated i945 chipset makes for sluggish graphics performance and that the i945's GMA 950 IGP is not able to decode HD signals. Anyone who has tried playing back high-def video on a N270-based netbooks knows the pain. However, both versions of the Atom score about the same on the two benchmark systems we use here at RuggedPCReview (PassMark 6.1 and CrystalMark 2004). The Z5xx, in fact, scored very low in 3D graphics, which one would assume are at least somewhat of importance in any "mobile internet device."
But things are getting more interesting yet. Despite what on the surface appears to be the more lucrative "Diamondville" market with its many millions of N270 chips, on April 8, 2009, Intel announced the expansion of the Z5xx platform with a new high-end version, the 2GHz Z515, and a new gas miser version, the "up-to-1.2GHz" Z515. At the same time, Intel spoke of an entirely new Atom platform called "Moorestown" that combines the "Lincroft" system-on-chip with the "Langwell" hub of which as of now all I know is that it uses a lot of acronyms and is still based on the 45nm manufacturing technology.
On the N2xx horizon, there is the N280 processor, and apparently also a dual core Atom chip. There is not much material out there on those, and I need to look more into it.
There was another development. For embedded computing Intel quietly expanded the Z5XX platform with larger form factor versions that carry a "P" in their name, and then special "large form factor with industrial temperature options" versions marked with a "PT." I was aware that Intel would release a "large package" version of the Atom, but not the timing and the purpose. Well, this happened in March of 2009 when Intel added the "large form factor" Atom 1.1GHz Z510P and 1.6GHz Z530P as well as the "large form factor with industrial temperature option" 1.1GHz Z510PT and 1.33GHz Z520PT. What does that mean? In essence, the P and PT versions look like larger chips. Instead of the tiny 13x14mm package of the original Z5xx chips, they use a 22x22mm package, which is actually the same size as the N2xx chips. As far as temperature range goes, 0 to 70 degrees Celsius (32 to 158 degrees Fahrenheit) is considered "commercial," whereas -40 to 85 degrees Celsius (-40 to 185 degrees Fahrenheit) is considered "industrial." Interestingly, only the "PT" series processors support the industrial temperature range; the "P" series versions are listed with the same commercial temperature range as the initial chips.
Intel's updated Z5xx product brief now stresses fairly strongly that there are industrial as well as commercal temperature range packages for both the Z5xx processors as well as for their complementing US15W system controller hubs (GMA 500 graphics, I/O controller and memory controller). The brief also stresses that the small footprint versions are for space-constrained handheld and embedded devices whereas the large form factor is pitched for designs without small space restrictions but industrial temperature requirements. So why then do the "P" processors still have the same commercial temperature rating? Probably because the large package also includes "an integrated heat spreader" that "further contributes to its value for thermally constrained, fanless applications." Since the thermal design power of these chips was already tiny, I am not sure what the integrated heat spreader does, or why it was necessary.
In terms of performance, the "P" large form factor and "PT" large form factor/industrial temperature range chips appear unchanged, though the TDP is up a bit from 2.0 to 2.2 watts. However, if you compare the Intel's summary sheets for the Z530 and the Z530P it looks like the 530P chip is missing Intel Virtualization Technology as well as Demand Based Switching. Virtualization technology, according to Intel, allows "consolidating multiple environments into a single server or PC" which I believe means the CPU acts as if it were multiple CPUs operating independently so you can run different operating systems at the same time. Demand Based Switching was described as an enhanced version of Intel's SpeedStep technology (see description) that is available in both versions of the Z530. These are generally fairly involved server-based issues and I am not sure what the relevance to the new "large package" Atom processors is.
In any case, the "large package" also has a different "ball pitch," which refers to the spacing of the little balls of solder that replace pins on the underside of these tiny processor packages. From what I can tell, the 0.6mm ball pitch of the original Z5xx series requires high density interconnects (HDI) on the printed circuit boards, and those are more difficult to do and also more finicky--not what one would want in a rugged product (for an example of these issues, read this). So the "P" series would address that issue with its larger package size whereas the "PT" series would appeal to automotive and other transportation and industrial applications that often have a -40 to 185 degrees Fahrenheit requirement.
Now add to this that Atom chips, despite all the hoopla and market acceptance, are pretty poor performers, benchmarking no better than the lowly original Core Solos. Graphics performance, especially, is weak (what's considered weak in one device can be more than adequate in another, of course). There's the low power consumption, of course, but even that is not a given. We've benchmarked exceedingly thrifty Core 2 Duo machines as well as power-guzzling Atom systems, so proper setup and configuration are an issue.
Sometimes it almost seems like the Atom is sort of a trial balloon, one where Intel very successfully created an attractive image of a hip processor, but is also somewhat aimlessly trying out various applications to see where the Atom will fit and stick.
Posted by conradb212 at April 10, 2009 2:20 PM