Arm's Cortex-A76 CPU Unveiled: Taking Aim at the Top for 7nm
by Andrei Frumusanu on May 31, 2018 3:01 PM EST- Posted in
- CPUs
- Arm
- Smartphones
- Mobile
- SoCs
- Cortex-A76
Conclusion & Thoughts
The Cortex A76 presents itself a solid generational improvement for Arm. We’ve been waiting on a larger CPU microarchitecture for several years now, and while the A76 isn’t quite a performance monster to compete with Apple’s cores, it shows how important it is to have a balanced microarchitecture. This year all eyes were on Samsung and the M3 core, and unfortunately the performance increase came at a great cost of power and efficiency which ended up making the end-product rather uncompetitive. The A76 drives performance up but on every step of the way it still deeply focused on power efficiency which means we’ll get to see the best of both worlds in end products.
In general Arm promises a 35% performance improvement which is a significant generational uplift. Together with the fact that the A76 is targeted to be employed in 7nm designs is also a boost to the projected product.
I’m having some reservations in terms of the performance targets and if vendors will indeed release the SoC with quad-core clock rates of up to 3GHz – based on what I’ve heard from vendors that seems like a rather very optimistic target. Even then, a reduced clock frequency still brings significant benefits, and it’s especially on the efficiency side where Arm should be lauded for continuing to place great focus on.
Whether my projections are correct or not is something we’ll have to see in actual products, but fact is that we *will* see significant efficiency benefits in the next generation of SoCs which should bring both an notable performance improvement as well as battery life improvement to the user. Arm’s focus here on the user experience seems to be exemplary and I hope vendors will be able to implement the core based on Arm’s guidance and reach the targeted metrics.
The Cortex A76 is said to have already come back in working silicon at two partners and we’ll very likely see it shipping in commercial products by the end of the year. I won’t be beating around the bush here as Huawei and HiSilicon’s product cycle schedule makes it obvious that they’re likely one of the launch partners for the product. Qualcomm has also doubled down on using Arm cores in the mobile space so we should also be seeing the next generation Snapdragon SoCs employ the A76. Among the big players, it’s Samsung LSI which is going to have a tough time – the A76 doesn’t seem to greatly outperform the M3, so at least in theory, the M4’s focus will need to be solely on power efficiency. Then again Arm is very open about their design goals; half the area and half the power at similar performance is something that’s going to be hard to compete against.
The Cortex A76 is said to be the baseline microarchitecture on which Arm will iterate over the next 2 generations at least. Arm has been able to execute their yearly beat roadmap on time for 5 generations now and with yearly 20-25% CAGR it’s going to be a very interesting next couple of years as the mobile space is very quickly approaching the performance of desktop CPUs.
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tipoo - Thursday, May 31, 2018 - link
Still a 4-wide front end, I don't imagine it'll catch A10, maybe A9 per core then eh.wicketr - Thursday, May 31, 2018 - link
I just don't understand why ARM doesn't at least come out with a design that can match the Monsoon cores of an A11, or even the power of what will likely be the next A12 cores. It seems like ARM is eternally 2-3 steps behind Apple on this and they need to catch up.shadowx360 - Thursday, May 31, 2018 - link
Probably their power/efficiency constraints. They manage to get the same performance as a M3 core with a 4 wide instead of 6 wide decoder and half the power usage. The A11 cores are absolute monsters at power draw at max performance but Apple is able to tweak the hell out of the rest of the device and OS to get the battery life in check. Android OEMs don't have that much control.wicketr - Thursday, May 31, 2018 - link
And I could understand the power issues for phones, but not all ARM chips are destined for phones. Some can go into cars or gaming consoles that are always plugged in and well ventilated.I just think they should come out with another tier ( Cortex A9X series) that can go toe-to-toe with Apple's best even if it is too power hungry for phones. Just come up with a design and see where we're at.
Wilco1 - Thursday, May 31, 2018 - link
Using a much larger core to get modest extra performance wouldn't make sense even in less power constrained cases. Not every market is happy with just 2 huge cores, so power and area efficiency remain important. For laptops binning for frequency and adding turbo modes would make far more sense.BillBear - Friday, June 1, 2018 - link
>Using a much larger core to get modest extra performance wouldn't make sense even in less power constrained cases.It makes perfect sense if you don't care that your core is large, because you aren't just selling a SOC. For Qualcomm, increased die size means reduced profit. For Apple, it does not.
For instance, Apple's Cyclone core from 2013:
>With six decoders and nine ports to execution units, Cyclone is big. As I mentioned before, it's bigger than anything else that goes in a phone. Apple didn't build a Krait/Silvermont competitor, it built something much closer to Intel's big cores. At the launch of the iPhone 5s, Apple referred to the A7 as being "desktop class" - it turns out that wasn't an exaggeration.
https://www.anandtech.com/show/7910/apples-cyclone...
Matthmaroo - Monday, June 4, 2018 - link
Apple has so many built in advantages - huge RD , excellent engineering, closed system ... android manufacturers are disadvantaged to Apple inso manu waysclose - Tuesday, June 5, 2018 - link
ARM has to build a "one size fits all" kind of solution. Unlike Apple they are not catering for a single customer with full control over every aspect of HW and SW development, and the profits associated with that.Plus, achieving the power that the Apple cores bring doesn't come cheap. Samsung's Exynos is still lagging behind and it's not like Samsung doesn't have expertise or deep pockets.
techconc - Tuesday, June 5, 2018 - link
Yeah, but when you have a big little architecture, OEMs could choose the most efficient combination to meet their needs. There needs to be a powerful single core option that's available for the ARM platform. Until ARM goes there, the rest of the ARM community will be behind Apple. Remember, not all workloads can take advantage of multiple cores. At best ARM will be approaching 2016 level Apple A series core performance.bananaforscale - Saturday, June 9, 2018 - link
Excellent engineering? Like the bendgate, touch screen problems etc. that were *engineering screwups*?