Galaxy Nexus now, or ARM Cortex-A15 later

(Note: I simplify a lot of performance characteristics based on process node and architecture, but I realize a lot of factors come into play, including instruction sets, to determine how fast a particular platform is)

I want a Galaxy Nexus (GSM version) very, very much. I have attempted to subsidize the cost somewhat by offering my Nexus S for sale on Craigslist (many offers, but none were serious). The Galaxy Nexus has its weaknesses (weak GPU, battery life, weak camera, lack of warranty when bought in the U.S., bastardization of the Nexus promise, really the bastardization of the Nexus promise), but undoubtedly it is still one of the best Android phones out right now and is far, far faster than my Nexus S. I have come so close to purchasing the Galaxy Nexus many times, but held back because of the >$500 price in combination with the issues above. Note, I purchased my beloved Nexus One for $529 straight from, and had with it proper warranty from HTC.

So a few days ago I managed to convince myself not to buy the Galaxy Nexus. Instead, I will wait for the next generation Nexus device. Not to say you should not buy a Galaxy Nexus if you NEED a new phone, but the fact is I have a Nexus S that can keep me going through 2012.

As with anything in the tech world: waiting means faster processor, hopefully better battery life. But let me explain in detail why it’s worth waiting.

2011 to early 2012 smartphones

Smartphones out right now are based on the Cortex-A9 design, and have been for the past 1.5-2 years. The Galaxy S II (45nm Exynos or 45nm OMAP), Apple’s iPhone 4S (Apple’s custom chip, the A5, 45nm), or to speak about specific processors, the Tegra 2 and Tegra 3 (both 40nm), they are all Cortex-A9 design.

In general, the shift that took place in mid-2011 is we went from single core Cortex-A9 to dual core Cortex-A9, and to a smaller node process (65nm to 45nm). Now (with the Tegra 3, and other upcoming chips) we’re moving to quad-core Cortex-A9 designs based on the same 45nm process.

Yet to be released 2012 smartphones

The Galaxy S III will likely utilize quad-core Cortex-A9 chips (probably Samsung’s Exynos, unless cellular carriers in the U.S. demand another company’s chip). Apple’s new iPad (the iPad 3, though that’s not its official name) has the A5X which is the same dual-core Cortex-A9 that the A5 had but with a beefier GPU. The iPhone 5 (or whatever it’s called) will have a processor most likely dubbed A6 and most likely will have a quad-core Cortex-A9 design as well.

My current phones:

I own the HTC Nexus One (January 5, 2010) and the Samsung Nexus S (released Dec 16 2010).

For a bit of perspective, my Nexus One was a Cortex-A8 design (but heavily modified by Qualcomm) built on the 65nm node, and the Nexus S is also a Cortex-A8 design (dubbed Exynos, Samsung’s own modifications) built on the 45nm node. As the name implies, my two phones are a generation behind the A9s, and “only” single core, and both run at 1Ghz.

The Galaxy Nexus was released Dec 2011 (in the U.S.). Just one year after the Nexus S the Galaxy Nexus not only jumped a generation in processor design to the Cortex-A9, but it was also dual core. (Although released so late in 2011, when the entire industry is shifting to quad core Cortex-A9 in 2012).

The Nexus S and the Galaxy Nexus use the same GPU (SGX 540), but the Galaxy Nexus has its SGX 540 clocked faster. My guess is in building Ice Cream Sandwich, Google wanted to bring tangible performance gains but write code that would maintain compatibility across previous generation Android phones (i.e. those released in 2011) and thus chose a weaker GPU. As I mentioned in a previous post a Nexus phone is a developer phone, the point is not to make it the fastest but to set a standard that other phones can aim to reach (including cheaper Android handsets) that developers can aim for in the hopes of maintaining compatibility when writing their apps.

Cortex-A15, my next Nexus?

By the end of 2012 and early 2013, Qualcomm will have Krait and Texas Instruments will have their OMAP 5 (and maybe Samsung will have their next gen Exynos 5xxx), which are based on the next generation Cortex-A15 design.

My hope is that because Nexus phones typically are released around December, it’s just late enough to be built around a Cortex-A15 design. Cortex-A15 is a large leap in technology over the Cortex-A9, with ARM (the company behind the Cortex designs) promising up to 40% increase in performance on the same clock/node. However Krait and OMAP 5 are going to be built on a 28nm node (Exynos, 32nm) and likely have faster clock speeds.

Therefore when I have a working smartphone that does the job, I cannot justify spending $500 (or even $200, if subsidized, locking myself into a contract) on a phone when we’re on the cusp of a generational processor leap. It is akin to moving from a Pentium 4 Extreme Edition processor (fast, but hot, inefficient) to a Core 2 Duo chip. I’m speaking strictly of the CPU right now, not the GPU in these phones.

There is a video that TI released showcasing the power of a dual-core OMAP 5 (Cortex-A15) vs a quad core Cortex-A9 (likely the Tegra 3) in a side by side, and the OMAP 5 smokes the quad core setup on what appears to be an Ice Cream Sandwich build of Android (see the 3 dots at the top right of each device’s screen, which is the new ICS thing).

Cortex A15 dual-core is faster than a Cortex A9 quadcore

This makes sense: you cannot make up for architectural improvements by slapping more cores on an older design (ahem, Pentium D vs Athlon X2 or Core Duo), the newer architecture almost always wins.

After Kal-El (Tegra 3), NVIDIA will release Wayne (Tegra 4) which is likely Cortex-A15 quad-core, so the jump between Tegra 3 and Tegra 4 will be even better than what you see in the video above (not to mention Tegra 4 will be built on a 28nm node vs Tegra 3’s 40nm).

So I will hang onto my dear Nexus S for another year and have high hopes that the next Nexus device (Nexus 4 is my codename) is running a next-gen core. My dream of owning every Nexus device released will have to be forgotten.


An Extremetech article on the Krait design (which is based on Cortex-A15 but designed by Qualcomm to be better than the ARM standard Cortex-A15):

Update 2: (9/14/2012)

I’m surprised, very surprised, but the recently announced iPhone 5 A6 is likely a dual-core Cortex A15, the first to market A15 chip. It is undeniably the best chip available in any smart phone at this time. (see Update 3 below)

Update 3: (9/15/12)

Okay I take that back, Anandtech was one of the first to suggest the iPhone 5’s A6 may be a dual-core Cortex A15 however it seems that’s not the case based on this:


2 thoughts on “Galaxy Nexus now, or ARM Cortex-A15 later

    • I’m sorry Sam, I do not. The information I got for this post was gleaned from tech sites such as Anandtech and ArsTechnica, and was much easier to find because generally they are higher profile releases. You’re right to wonder about Broadcom’s AP as it has a significant impact on phone performance too but that technology is not covered as widely.

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