ARM Cortex A9 vs Intel Atom N450 Pine Trail
While I am eagerly waiting for the smartbook product introductions at 2010 CES, I am wondering what kind of performance we can expect from those upcoming ARM based tablets and netbooks. Although some of the smartbooks will be based on Cortex A8 technology, I believe only the more performant, dual-core Cortex A9 system-on-chip (SOC) designs will be really successful (see this about the A8).
Since newer Pine Trail Atom netbooks are already getting fairly good battery runtimes, the question is unavoidable for the smartbooks: will we get at least similar performance to the Atom based netbooks? New Intel based netbooks will mostly use the netbook-oriented Atom N450 chip (Pine View), so I will try to draw a comparison between this chip and the known characteristics of A9 SOCs.
Since it is extremely hard to come by good comparative data between ARM and Atom, partly because Cortex A9 based systems are not yet available for the public, this post is highly speculative and by no means should serve as the basis for purchasing your next smartbook/netbook.
By ARM’s specifications, the Cortex A9 core has an approximate raw performance of 2.5 DMIPS/MHz. It can run at 2Ghz when produced on the 28nm GlobalFoundries process. This is 5000 DMIPS/core with an expected 10000 DMIPS for a dual core setup (MP CORE version).
Since it is more likely that the first A9 SOCs will be manufactured with a 40nm process, we only calculate with a 1.5 Ghz top frequency which would yield about 7500 DMIPS.
Now, performance wise. the new N450 is only marginally better that the earlier Atom chips (5-10%, see this Anandtech article) and several discussions report that the older Atoms get 2.5 DMIPS/Mhz, a 1.6 Ghz Atom yields about 4000 DMIPS (one of the discussions). Pine View Atoms for netbooks (N450 descendants) are not planned to be made dual-core in the near future so we calculate with only one core.
I am aware that this is not a perfect comparison since DMIPS values between different architectures are not 100% comparable, but these results would mean an 80% advantage in raw power for the dual-A9.
Some more considerations:
All recent ARM chips include hardware decoders for H264 video while the N450/NM10 has no such capability. This means either choppy HD video from Youtube or an external H264 decoder chip (like the Broadcomm one or an Nvidia Ion like extension). Certain Cortex A9 SOCs promise multiple 1080p stream decoding in parallel (like the Tegra 2) without loading the general purpose ARM core. Moreover, in the case of the N450, the maximum output on hdmi is restricted to 1366×768 (1440×1050 for the analog vga out). So you can forget about viewing HD videos with your Atom netbook even if you have an external, HD monitor or TV.
Flash hardware acceleration is coming (with Flash 10.1) to all ARM machines with H264 decoders but in case of the N450 alone, there is nothing to accelerate with. So you better check whether your Atom netbook has the external video decoder or you will never watch streamed hd videos with decent speed. It is fully possible that Nvidia won’t produce a new ION chipset for the new Atoms since Intel denied access to the relevant hw interfaces. Instead, Nvidia will work even harder on Tegra 2.
Architecture wise: the new Pine View Atom remains in-order architecture, produced on 45nm while the Cortex A9 is out-of-order core (more modern, inherently more powerful than the Atom) with easy implementation on the TSMC 40nm process and the GlobalFoundries 28nm process.
The n450 SOC and the NM10 companion chip(set) still works in a 6.5w TDP while the dual-A9 SOCs are expected to work in a 2W TDP. This is massive difference and makes it likely that the same battery will last much longer with an A9 smartbook than with an N450 netbook. The N450 doesn’t need active cooling anymore (this is good news) so the new machines will not have fans but the TDP values above indicate that Atom netbooks will likely be hotter than A9 based smartbooks especially in continued use.
The third generation Atoms – which could improve the situation – will come only in 2012, seriously late compared to A9 based chips (1Q 2010).
It very much seems that dual core Cortex A9 SOCs will be at-least on-par with the Pine View N450 Atom, performance wise, and possibly overpower them by 50-80% in raw processing power. Graphics performance, end-user price and battery runtimes are also expected to be much better for the A9 based machines.
Unless, Intel comes out with much more powerful Atom designs for netbooks, ARM Cortex A9 based smartbook products may severely cut into Atom netbook sales. X86 compatibility is less of a factor in this segment, so consumers may decide based on perceived performance, battery runtime in which A9 smartbooks seem to have the advantage.