The Qualcomm Snapdragon S4 (Krait) Preview Part II
by Anand Lal Shimpi on February 22, 2012 11:40 PM EST- Posted in
- Smartphones
- Snapdragon
- Qualcomm
- Krait
- Mobile
- Tegra 3
- Tablets
- NVIDIA
Final Words
As I mentioned at the start of this comparison, we're trying to compare two SoCs in two platforms that may offer wildly different experiences than shipping devices based on these SoCs. The hope (on both sides) is that we'll see similar, but likely slightly lower performance in phones. The reality will have to wait until we have final hardware in hand.
Qualcomm's strengths are clearly single/lightly threaded CPU performance as Krait is able to offer some significant steps forward in that department. Tegra 3 can hold onto an advantage in heavily threaded apps, but I'm not entirely convinced that in phones we'll see a lot of that.
The bigger question is about power efficiency, and this is the one not as easily answered based on what we know today. Qualcomm gains a lot by being on a 28nm LP process, however it also has more power hungry cores on that process. Device level power efficiency for a given workload may truly improve as a result of having faster cores on a lower power process (race to sleep, lower power idle). Generally speaking however, single threaded performance often comes at the expense of core level power efficiency. That's the reason it's taken this long for a 3-wide out-of-order core to make it into a smartphone. Will Moore's Law, and the 28nm LP process in particular, be enough to offset the power consumption of a higher performance Krait core under full load? Depending on how conservative device makers choose to build their power profiles we may get varying answers to this question.
Tegra 3 on the other hand should be a known quantity from a power consumption standpoint. All of the A9s in Tegra 3 are power gated (unlike in Tegra 2) and there's the fifth core for light workloads. For typical usage models I would expect better battery life out of Tegra 3 phones compared to Tegra 2 counterparts since the extra cores will likely be power gated, and idle power consumption should be lower. It's only for the heavier workloads where all cores are engaged that the impact of Tegra 3 remains to be seen.
There's also the LTE component. Today we're focused on the SoC comparisons however the first MSM8960 devices will also benefit from having integrated 28nm LTE baseband as well. Qualcomm will also have discrete 28nm LTE baseband solutions as well (e.g. MDM9615) for device makers who choose not to use Qualcomm application processors.
We'll obviously figure all of this out in due time, but my final concern remains with the device vendors. Far too often we review great platforms that are burdened with horrible software sold under the guise of differentiation. We're finally on the cusp of getting some really powerful smartphone hardware, I do hope the device vendors do these SoCs justice.
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lancedal - Thursday, February 23, 2012 - link
Hi Anand,What is the CPU voltage for the 1.5GHz?
boostern - Thursday, February 23, 2012 - link
It's been almost 10 years that I'm following you.It's always a joy to read one of your articles.
Thank you Anand, really.
Black1969ta - Thursday, February 23, 2012 - link
Tegra 2 was out before other dual cores and fell short of those later designs, it is not surprising that Tegra 3 is in the same position performance wise.Any one have a link to more news on Kal-El+, other than just name?
Is Kal-El+ a tock, to Kal-El, from Intel's Playbook?
If it is then I could see not only a process shrink down to 28nm or 32nm, but "tweaks" also.
Perhaps with the smaller process they could add a 2nd Memory channel.
The HTC One X is rumored to be a 1.5 GHz Tegra 3, instead of the 1.3Ghz in the Prime.
Lucian Armasu - Saturday, February 25, 2012 - link
If they actually really the Tegra 3+ this year (they were supposed to release the Tegra 2 3D too last year but didn't because they were late), it will probably be a quad core with at least the first core at 1.8 Ghz or even 2 Ghz, and the others a little lower.It should be at least at 2 Ghz if they want to compete with Krait. The problem is, although they were already very late with Tegra 3 to market, they also only release the tablet version first, and the phone version months later. So Krait phones will be available in Q2 this year, Tegra 3+ tablets probably in Q3, and Tegra 3+ phones late Q3 or early Q4.
If Nvidia actually managed to deliver their chips when they promised they would deliver them, I think they would be in a much better position today, because for example it would be understandable if Krait is more powerful than Tegra 3 in Q2 2012, if phones with Tegra 3 started appearing 2 quarters earlier, like they promised. But that didn't happen, so now once again Tegra 3 is late to market, just like Tegra 2 was, and the competition is already better by the time it starts to get a foothold in the market.
fteoath64 - Friday, February 24, 2012 - link
Nvidia better get to A15 very quick!. They are getting creamed by the strong competition. Here is my suggestion. Stop with the quadcore nonsense. Do a 1+1 (big.little at 2Ghz, dual ch ram), 2+1 and 3+1 for good measure. If they can make the 3+1 to turbo at 2.2Ghz with single core, it would be great.Also to find a way to retask the small core to be I/O processor when it is inactive.
curtisas - Saturday, February 25, 2012 - link
Can Qualcomm just make that device have a little less of a lip on the bottom and sell me it? It's running stock Android which is awesome, and the reference devices always have the top of the line hardware!gamoniac - Saturday, February 25, 2012 - link
I am reposting my comment on an earlier article by Brian --
The browsers are multi-threaded but javascript does not support multi-threading until the advent of web worker in HTML 5. Although the browser could load images/files with multi threads, javascript snippets on a pre-HTML 5 page only runs in one thread. Was SunSpider's benchmark written in HTML 5?
thebeastie - Monday, February 27, 2012 - link
Now I got a Sony HMZ-T1 all I really care about is how well it can handle a Bluray 13GB MKV rip of Avatar 3D that I may have on local file server or off the device it self so I can go into my bedroom and watch a 3D movie at highest quality possible with no mess or fuss of a PC.ATM iPad2 can't handle my really high end rips and I don't want to buy a laptop etc for my bedroom, I want something simple like a tablet.
superg05 - Saturday, March 10, 2012 - link
these so called standard benchmarks only show so much let me see a benchmark that shows how many cores are running for tegra 3 for example for browsing only suppose to use the companion lower core how many cores and gpu cores during the test is each different system running?