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Comment by plantsbeans | Hacker News Reader

They mention “performance/area” as being dramatically better than Cortex-A75. I’m not familiar with whether area is expected to relate to power usage.

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>They mention “performance/area” as being dramatically better than Cortex-A75.

The P550 pref / area based on Intel 7nm equivalent to TSMC 4nm / 3nm that is better than the ARM Cortex A75 released in 2017 on TSMC 10nm.

Number using Intel CPU's 7nm, normally Custom Foundry of IFS tends to offer lower density but higher flexibility. So this is more like a best case scenario.

I am also suspicious of the Intel 7nm number. There are some possibility this is actually an Intel 10nm renamed to 7nm for custom foundry partners. ( Intel 10nm being equivalent to TSMC 7nm )

No, the area numbers quoted are for TSMC N7. You can look up comparable A75 die area numbers for N7 as well. A Cortex A76 on TSMC N7 takes up 1.27mm with L2 included. A P550 takes up 0.38mm.

As per Intel announcement and Anandtech [1] while not explicityly stated, the P550 number are from Intel 7nm Intel Foundry Services. I am not sure where that TSMC N7 came from.

[1] https://www.anandtech.com/show/16777/intel-licenses-sifives-...

SiFive likes to include just enough resources to do well on their benchmark du jour (was dhrystone, now SPECint) and leave out the rest. So they end up comparing an Arm core with NEON against their RISC-V cores with no SIMD/vector support for example.

Previous cores had no vector support because the V extension that provides for it was nowhere close to being standardized. In fact it's yet to be ratified at present, so one may want to wait for that before choosing a V-capable core for real, actual use.

Which is fine because what would normally be handled by the SIMD will be custom silicon for most customers and have a 4-100x speedup over what SIMD could provide.

perf/area comes with a huge number of caveats and it basically doesn't mean anything as given.

For example, the exact same verilog, on the same process node at the same foundry, can synthesize to very different areas depending on the standard library used. They come in a lot of varieties with a lot of different trade offs.

For even more detail, the SkyWater130 node, which has been popular on HN lately and is public so we can actually post links to it, has 6 different mappings that are possible. Note, some are called high speed, or high density, etc. You get the idea.

https://skywater-pdk.readthedocs.io/en/latest/contents/libra...

I'm not even why we're supposed to care about a newly launched core beating one that was released in 2017. If that's the bar they've set, I'm not exactly wowed.

Gotta start somewhere

Because the ARM core still has a large market and not every application need the maximum performance so having competition in that market is not good.

And you are not 'supposed to' care. You can care if you want, and ignore it if you want. So I don't really get your attitude here.

ARM has a head start of many years and billions of dollars. The fact that this is comparable to an ARM processor of a few years ago is a good sign.

So we're grading on a curve.

Look at the trajectory for ARM catching up with Intel. The trajectory for RISC-V is even faster. That’s at least mildly indicative of where the future is headed.

Past performance is no indication of future returns, especially when it's someone else's performance.

The first 4 minute mile record was set in 1954. Now there are a bunch of people who have done it. Once formerly new techniques start to be known and distributed, it becomes much easier to catch up.

Remember, RISC-V doesn't have to beat ARM -- only come close enough that the price differential outweighs the performance difference. This is already happening on the low-end end and it's only a matter of time (IMHO) before this becomes reality on the high-end too.

Not every task requires the latest and fastest CPU. ARM makes and sells a huge number of smaller slower lower power cores -- numerically far more than the high end cores in SmartPhones -- and RISC-V is there competing with all but the very high end.

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