Most people probably won't give much thought to the processor that comes with a tablet PC. The type and speed of a processor can make a huge difference in the overall functionality of a tablet. Because of this, it should be something that most buyers are at least aware of. In general, companies will probably mention things like the speed and number of cores but it can be a bit more complex than that. After all, two processors with the same base specs may have very different performance. This article takes a look at some of the typical processors used for tablet PCs now how to look at them when considering the purchase of a tablet PC.
ARM Processors
The majority of tablet use a processor architecture that was produced by ARM This company works differently than many others in that it designs the basic processor architecture and then licenses those designs out to other companies that can then produce them. As a result, you can get similar ARM based processors manufactured by a wide range of manufacturers. This can make it a bit more difficult to compared two tablets without having a bit of knowledge.
The most dominant of the ARM processor designs to be used within tablet PCs is based on the Cortex-A. This series is comprised of four different designs that vary in their performance and features. Below is a list of the four models and the features they have:
- Cortex-A5 - Lowest power consumption, generally single core, frequencies between 300 and 800MHz
- Cortex-A8 - Modest processor with better media performance than A5, generally single or dual core, frequencies between 600MHz and 1.5GHz.
- Cortex-A9 - Most popular of the processors, typically dual core but available with up to four, frequencies between 800MHz and 2GHz.
- Cortex-A15 - Newest processor design that is not very common yet, typically dual or quad core, frequencies between 1GHz and 2GHz
As mentioned before, this is just the basis for the ARM based processors. Each manufacturer can make some small changes to the design but for the most part, performance will be very similar between products within the same base design. This means that Apple's A6 and NVIDIA's Tegra 3 which are both based on the Cortex-A9 with dual cores and similar clock speeds will have very comparable base speed. The actual speeds can differ though because of the amount of memory, the operating system run on each platform and the other hardware such as the graphics processor. However, if one processor is based on the Cortex-A8 while another is the Cortex-A9, the higher model will typically offer better performance at similar speeds.
x86 Processors
The primary market for x86 based processor are tablet PCs that run the Windows 8 operating system. This is due to the fact that the existing versions of Windows are written for this type of architecture. Microsoft has released a special version of Windows 8 called Windows 8 RT that will run on ARM processors but this does have some big drawbacks that consumers should be aware of that make it different than a traditional Windows 8 tablet.
The two major suppliers of x86 processors are AMD and Intel. Intel is the most frequently used of the two thanks to their low power Atom processors. While they don't have the same levels of efficiencies as ARM based chips, they still provide sufficient performance for running Windows albeit below the level of traditional laptops. This means that they have more in common with netbooks in terms of their capabilities. Now, Intel offers a wide range of Atom processors but the most common series to be use for tablets is the Z series because of its lower power consumption and reduced heat generation. The downside to this is that these processor typically have lower clock speeds than traditional processors which limit their potential performance.
Serious business class tablet PCs are on the market that use the new energy efficient Core i series processors similar to what is used in the new class of ultrabooks which are also being designed now as hybrids of laptops and tablets with the Windows 8 software. This means that they offer a similar level of performance but generally are not as compact or have the same level of running times as the Atom based processors.
AMD also offers several processors that could be used in tablet PCs. These are based on AMD's new Fusion architecture that they like to call an APU or Accelerated Processing Units. There are three versions of the APU that could be used for tablets. The Z series is the most recent and most likely to be found in a Windows 8 specific tablet. It should offers performance similar to that of the latest Intel Atom Z series but is seeing limited introduction. Other AMD APUs could come from the C and E series models that have been used in the past for netbooks and low power low cost laptops but they are again seeing limited use by manufacutrers.
Here is a breakdown of the x86 processors in terms of performance from least to most powerful:
- Intel Atom Z Series
- AMD Fusion C Series
- AMD Fusion Z Series
- Intel Atom N Series
- AMD Fusion E Series
- Intel Core i3 ULV Series
- Intel Core i5 ULV Series
Just remember that the faster the performance of the x86 processor, the more power it will typically consume and the larger the tablet will generally have to be in order to properly cool off the processor. Similarly, it will likely have a shorter battery life due to increased power consumption. Prices will also be more expensive the more powerful the processor is as well.
Why Number of Cores Matter
Most software now is written to take advantage of multiple processors cores. This is referred to as multi-threaded software. The operating systems and software can allocate tasks to be run in parallel between two different cores within a processor to help speed up the performance compared to running on a single core. As a result, a multiple core processor is generally advantageous to a single core processor.
In addition to having multiple cores help speed up a single task, it can make an even bigger difference when the tablet will be used to multitask. A good example of multitasking is using a tablet to listen to music while also surfing the web or reading an e-book. By having two processors over one, a tablet PC should be able to better handle the tasks by assigning each to an individual processor core rather than having to swap both processes between a single processor core.
In terms of numbers of cores, there are also issues. Having too many cores can also increase the size and power consumption of a tablet PC. While it is possible to have up to four cores, most tablet PCs software have a limited set of capabilities that will not really benefit from more than two cores. Four cores would certainly help with multitasking but it won't be as beneficial as most tasks that are run simultaneously are fairly modest in their power consumption where having additional cores is not a noticeable benefit. This may change in the future though as tablets become more widespread and what they are used for evolves.
Another feature that is being introduced into tablet processing is variable processing. This is essentially taking two different processor architecture designs into a single chip. The concept is that one lower power core can take over when the tablet doesn't need to do much work. This helps reduce the overall power consumption and presumably increase battery life. Don't worry, if you still need high performance, it will ramp up by using the larger processing cores as needed.
