The Samsung Galaxy S6 and S6 edge Review
by Joshua Ho on April 17, 2015 9:00 AM EST- Posted in
- Smartphones
- Samsung
- Mobile
- Galaxy S6
- Galaxy S6 Edge
Exynos 7420: First 14nm Silicon In A Smartphone
This generation more than any generation in recent memory has been a time of significant movement in the SoC space. We were aware of the Exynos 7420 well before it was announced in the Galaxy S6, but for the most part I expected to see Snapdragon 810 in at least a few variants of the Galaxy S6. It was a bit surprising to see Samsung drop Snapdragon SoCs completely this generation, and judging by the battery life of the Galaxy S6 it seems that Samsung had their reasons for doing this.
For those that are unfamiliar with the Exynos 7420, this SoC effectively represents the culmination of their efforts in semiconductor manufacturing and integrated circuit design. On the foundry side, Samsung is leveraging their vertical integration to make the first SoC on their 14nm LPE (Low Power Early) process, which seems to be solely for Systems LSI until they can no longer use all production capacity.
We previously mentioned that Samsung’s 14nm process in general will lack any significant die shrink due to almost unchanged metal interconnect pitch, but this assumption was in comparison to their 20nm LPM process from which the 14nm LPE process borrows its BEOL (back end of line) from. Opposite to what we thought, the Exynos 5433 was manufacturered on a 20LPE process which makes use of a quite larger metal layer. The result is that one can see a significant die shrink for the 7420 as it is, according to Chipworks, only 78mm² and a 44% reduction over the Exynos 5433's 113mm². This is considerable even when factoring in that the new SoC had two added GPU shader cores. Beyond the swap from a LPDDR3 memory controller to a LPDDR4 capable one, the only other at first noticeable major functional overhaul on the SoC seems to be that the dedicated HEVC decoder block has been removed and HEVC encoding and decoding capability has been merged into Samsung's MFC (Multi-Function Codec) media hardware acceleration block.
Galaxy S6 PCB with SoC and modem in view (Source: Chipworks)
The move from a planar to FinFET process is crucial. Although this is covered in more detail in previous articles, the short explanation is that planar processes suffer from increasing power leakage at smaller process nodes as the bulk of the silicon becomes relatively more massive than the gate that controls the flow of current. This causes decreased power efficiency as the power source of the transistor starts to act as a gate itself. FinFET solves this problem by attempting to isolate the transistor from the bulk of the silicon wafer, wrapping the gate around the channel of the transistor to ensure that it retains strong control over the flow of current compared to a planar transistor design.
The effective voltage drop allowed by the process can be substantial. We can have a look at some voltage excerpts of common frequencies available on both the Exynos 5433 and 7420:
| Exynos 5433 vs Exynos 7420 Supply Voltages | ||||||
| Exynos 5433 | Exynos 7420 | Difference | ||||
| A57 1.9GHz (ASV2) | 1287.50mV | 1056.25mV | -234.25mV | |||
| A57 1.9GHz (ASV9) | 1200.00mV | 975.00mV | -225.00mV | |||
| A57 1.9GHz (ASV15) | 1125.00mV | 912.50mV | -212.50mV | |||
| A57 800MHz (ASV2) | 950.00mV | 768.75mV | -181.25mV | |||
| A57 800MHz (ASV9) | 900.00mV | 687.50mV | -224.50mV | |||
| A57 800MHz (ASV15) | 900.00mV | 625.00mV | -275.00mV | |||
| A53 1.3GHz (ASV2) | 1200.00mV | 1037.50mV | -162.50mV | |||
| A53 1.3GHz (ASV9) | 1112.50mV | 950.00mV | -162.50mV | |||
| A53 1.3GHz (ASV15) | 1062.50mV | 900.00mV | -162.50mV | |||
| A53 400MHz (ASV2) | 862.00mV | 743.75mV | -118.25mV | |||
| A53 400MHz (ASV9) | 787.50mV | 656.25mV | -131.25mV | |||
| A53 400MHz (ASV15) | 750.00mV | 606.25mV | -143.75mV | |||
| GPU 700MHz (ASV2) | 1125.00mV | 881.25mV | -243.75mV | |||
| GPU 700MHz (ASV9) | 1050.00mV | 800.00mV | -250.00mV | |||
| GPU 700MHz (ASV15) | 1012.50mV | 750.00mV | -262.50mV | |||
| GPU 266MHz (ASV2) | 875.00mV | 750.00mV | -125.00mV | |||
| GPU 266MHz (ASV9) | 800.00mV | 668.75mV | -131.25mV | |||
| GPU 266MHz (ASV15) | 762.50mV | 606.25mV | -156.25mV | |||
The ASV (Adaptive Scaling Voltage) numbers represent the different type of chip bins, a lower value representing a worse quality bin and a higher one a better quality one. Group 2 should be the lowest that is found in the wild, with group 15 representing the best possible bin and group 9 the median that should be found in most devices. As one can see in the table, we can achieve well up to -250mV voltage drop on some frequencies on the A57s and the GPU. As a reminder, power scales quadratically with voltage, so a drop from 1287.50mV to 1056.25mV as seen in the worst bin 1.9GHz A57 frequency should for example result in a considerable 33% drop in dynamic power. The Exynos 7420 uses this headroom to go slightly higher in clocks compared to the 5433 - but we expect the end power to still be quite lower than what we've seen on the Note 4.
On the design side, Systems LSI has also done a great deal to differentiate the Exynos 7420 from the 5433. Although the CPU architectures are shared, the A53 cluster is now clocked at 1.5 GHz instead of 1.3 GHz, and the A57 cluster at 2.1 GHz rather than 1.9 GHz. The memory controller is new and supports LPDDR4 running at 1555MHz. This means that the Galaxy S6 has almost double the theoretical memory bandwidth when compared to the Galaxy Note 4 Exynos variant, as we get a boost up to 24.88GB/s over the 5433's 13.20GB/s. We still need to test this to see how these claims translate to practical performance in a deep dive article in the future, as effective bandwidth and latency can often vary depending on vendor's memory settings and SoC's bus architecture.
Outside of the memory controller, LSI has also updated the 7420 to use a more powerful Mali T760MP8 GPU. Although the Exynos 5433 had a Mali T760 GPU as well, it had two fewer shader cores which means that achieving a given level of performance requires higher clock speeds and higher voltages to overcome circuit delay. This new GPU is clocked a bit higher as well, at 772 MHz compared to the 700 MHz of the GPU in the Exynos 5433. We see the same two-stage maximum frequency scaling mechanism as discovered in our Note 4 Exynos review, with less ALU biased loads being limited to 700MHz as opposed to the 5433's 600MHz. There's also a suspicion that Samsung was ready to go higher to compete with other vendors though, as we can see evidence of an 852 MHz clock state that is unused. Unfortunately deeply testing this SoC isn’t possible at this time as doing so would require disassembling the phone.
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akdj - Sunday, April 26, 2015 - link
I'll re-read, but I could've sworn that was mentioned a couple times. Maybe it was ARS, but I'll check, as you're right. SVoice is the 'front end' to access GVoice and therefore allows Sammy to 'remember' your search information, etc. I've been able to work around, I believe, on my Note 4 now with the 5.0.1 updateUse Google Laincher. Disable Samsung account and sync and mine flies! Much faster than Nova, Go or vanilla TouchWiz and 'possibly' part of Google's Launch code, while using its only syncing data through Google (possibly SVoice or SRememberEverything in the background). I'll have to recheck and time but the update to LP has certainly sped all facets of the UI, updates, app launching and all around perceived 'speed'. I use a dark wallpaper, Nova Launcher 70% of the time and GLauncher the other portion.
Possibly Google's new 5.0.1 code is more specific to usage of its own services overriding those of carrier or the OEM. Again, unsure but damn it flies!
I'm going to spend this week with Google's camera to see if the Note 4 fan shoot the new raw still formats. As a decent camera with Lightroom on board and a CC subscription, I'm excited for the raw output of these hamdsets.
Are you speaking from experience? (Do you own one) or what you've read in reviews? I've certainly seen that mentioned and thought it was here ...pertaining to your suggestion it was forgotten. When I read it, I checked it in the Note 4 and using TW straight, indeed it runs through SVoice first with a significant delay (regardless of bandwidth). It seems quicker in Nova, slower in Go, fastest using Google Launch
pSupaNova - Tuesday, April 21, 2015 - link
Reading this review I can't help thinking Intel is in trouble if Samsung manages to ship lots of this handset.it will show that they are getting their SOC manufacturing into gear.
Schickenipple - Tuesday, April 21, 2015 - link
It's a little comical that a good portion of the 'pluses' of android phones have now gone the way of the iPhone. I fear there will be very little for Samsung lovers to hold over iOS soon.... How will you reboot when the OS freezes every day? Can't add an SD card??!! Blasphemy!Seriously though, they look pretty nice. Almost like an iPhone.
FlushedBubblyJock - Friday, April 24, 2015 - link
oh but if feels so industrial designed and so well built in my hand its so ergonomic my money impression is very, very high as my brain has been fried to a crisp from my desire to be somebody important and wealthy...FlushedBubblyJock - Friday, April 24, 2015 - link
excuse me but i have too go visit steve jobs grave for my monthly pilgrimage, and check my stock portfolio for my apple daily increase, an apple a day keeps retirement at bay !!!holmberg - Wednesday, April 22, 2015 - link
Could we get a measurement of the audio quality (i.e. the DAC and amplifiers, NOT the speakers), similar to what you did for the S5 here:;http://anandtech.com/show/8078/smartphone-audio-te...
FlushedBubblyJock - Friday, April 24, 2015 - link
oHHMMM ah I have recieved a premonition:When the time comes, metal industrial apple clone design won't be the glossy cocktail party rave it is now for all the reviewers... the new "nano carbon" hardshell and totally black design will be the inherently desired feel it up in the hand "win" the reviewers and crybabies all claim we want.
So, soon enough, when it's as cheap as a popcan is now, carbon fiber phone rage will storm the gates.... oh it's so light and so stiff, it feels so strong in my hand (like a fem commenting) ...
YEP - that's coming next - then after the reviewers convince the whole industry to trend toward carbon fiber and leave the metalheads in the dust (their newly created idiots wake) we will have another brain fart of gigantic proportion to deal with...
Warnings about carbon fiber slivers will go unheeded - there may be a whole section on how to reduce scratches and nano crackings and splittings of the fiber along with sales kits and superglue derivatives to rebond the nano cracks...
Next some of the more fervent feeler uppers will wind up in the hospital witth carbon paw poisoning or necessary eye cleansings since they sneezed up the raw carbon tubes into their own faces...
In the mean time they will have alzheimers from feeling up their aluminum metalized wonder industrial builds....
Yep, coming soon to a raw brain fart industry of elite 1% self love.
Forget that plastic if flexible, moldable, much more comfortable in the hand, lighter, and easily snapped apart and together - we must now have metal with apple 5star hex screws - and soon only carbon fiber probably with glass reinforced or ceramic fastener holes... and the elite will rave at the sensational high quality super high $$$$$ feel in their paws...
Yeah man, it's coming - if they charged ten grand for solidified rice paper the elite and feely nerd ego wackos would praise it to the moon and sky...
FlushedBubblyJock - Friday, April 24, 2015 - link
Where the heck is the scree resolution comparison and the pixels per inch chart putting the apple fans to shame ?I just read elsewhere the ppi which was always fanfare here when apple had the lead is 557 ppi ...
That's way above the 200-300+ I'm used to seeing...
So it's 4k resoluion and 557 pixels per inch - doesn't that deserve a whole page of glorious praise comparing to the other losers, which is everyone is it not ?
ubcjack - Tuesday, April 28, 2015 - link
Can Anandtech write an article to explain how Samsung implement PDAF over Sony's IM240 sensor? I'm really interested in the implementation.DIYEyal - Thursday, April 30, 2015 - link
If this phone was thicker with a bigger battery, dual sim, micro SD and waterproof it would have been the perfect phone for me.Rumors suggest that samsung is about to release a dualsim version, so I'll probably buy that.