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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wimbet - Thursday, February 23, 2012 - link
Thanks for posting comparisons with Tegra 3. It will be real interesting to see how OMAP4470 and Exynos4412 match up. I have a feeling we will see a lot more of OMAP5 and Exynos5250 at MWC as well.AmdInside - Thursday, February 23, 2012 - link
When are Krait 4 phones due? Still a while before my plan expires but just curious.infra_red_dude - Thursday, February 23, 2012 - link
Apparently MWC will see the launch of MSM8960 consumer devices.douglaswilliams - Thursday, February 23, 2012 - link
"I do hope the device vendors do these SoCs justice.""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."
Anand, perhaps some justice could lie in allowing user selectable power profiles, as on laptops. Let the user jump to a performance profile while playing a game or plugged in. Is that a possibility? Or will they just attempt to do that automatically in their stock power profile?
Wishmaster89 - Thursday, February 23, 2012 - link
Asus already did something like that with transformer prime so there's a possibility that with Krait powered padfone they could do the same thing. And don't forget that up till now Asus was quite good when it came to optimized software. So I have high hopes for Krait based Asus padfone with LTE radio.Perfect when connected to the tablet docking station.
Pipperox - Thursday, February 23, 2012 - link
It already happens, sort of.Any CPU governor will lower the CPU clock for light workloads, and max it out for games.
It's for the intermediate situations where you can see a big difference.
Anyway, this will be used on Android phones.
Hence, it'll be rooted in the blink of an eye, and custom kernels will offer multiple choices to the users concerning governors, so battery or performance optimized profiles.
ratn9ne - Thursday, February 23, 2012 - link
At&T doesn't even sell the galaxy nexus yet... so I expect this to be out sometime 2015.Loki726 - Thursday, February 23, 2012 - link
Anand,Can you comment on the Tegra 3 perf difference on sunspider in this review compared to your previous transformer prime review? This figure shows a score of 2300, and the previous figure in the transformer prime review shows a score of 1600. That's a pretty significant difference. Is there some change in the configuration that can explain this?
I saw that you mentioned a regression going from honeycomb to icecream sandwich, but then
you say that you included the faster honeycomb results.
Thanks
rahvin - Friday, February 24, 2012 - link
Without looking at the previous review, this review was clear that the Transformer had recently been upgraded to ICS. For those of you that haven't used ICS yet, it's significantly faster than Gingerbread on the same hardware.Gideon - Thursday, February 23, 2012 - link
"Oh the things I would do for an Unreal Engine 3 benchmark on Android..."Second that !
I don't think I have seen a single review/preview of a phone on Anandtech for the last year that doesn't include the same message. Hopefully the devs will finally notice.