Live data from Hacker News

AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

zdnet.com

131–140 of 165 posts

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#131
post #127

Earlier quoted context omitted.

Is AVX512 really an advantage though? Intel is infamous for severely downclocking the processor for these and other AVX/SSE family instructions, to a point where sometimes using them makes the program slower than it would be otherwise, especially if you're constantly provoking frequency switches between them and regular instructions. AMD might not have implemented AVX512 specifically yet (there's nothing legally keep…

I personally run AMD at home, but in all the benchmarks I have seen, Intel wins by a large margin in AVX enabled tasks - often double the speed. Downclocking did not seem to be a factor here. I think saying that Intel wins in AVX tasks is absolutely fair. For example, I had a simulation that had to run on the CPU for reasons, but made use of AVX. Intel was consistently faster on any system I tested.

The 7nm Ryzen parts should have double the avx2 as the older parts. Zen1 has half the throughput per cycle (or twice the reciprocal throughput) when using ymm (256 bit) registers vs xmm (128 bit) in general

https://www.agner.org/optimize/instruction_tables.pdf

If you want to look at `vmov`s or arithmetic like `vadd` or `vmul`. Particularly glaring is that for moves between memory and (xmm vs ymm) Zen1 has a recirpical throughput of (1 vs 2), ie that on average it is able to complete an xmm-memory move once per cycle, and a 256-bit move one every two cycles. Skylake-X instead has 0.5 for xmm/ymm/zmm-memory. That is, it can move up to 512-bits between a register and memory twice per cycle. That is 8-times the throughput.

Arithmetic isn't as bad, but Zen1's reciprocal throughput goes from 0.5 to 1 on xmm to ymm, while Intel stays at 0.5 independent of vector size.

I haven't seen data on the 7nm Ryzen parts, but their marketing claimed it was supposed to have full width avx2, so I imagine things are different now, and that 7nm Ryzen will do just as well for avx workloads per core and clock as all the Intel parts without avx512.

EDIT: Some instructions on Intel get slower with wider vectors, like vdiv, vsqrtpd, vgather...

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#132

I'm ignorant in stock trading, I admit. But I dont understand why AMD stock isn't blowing up. It's done a recovery after a market wide dip, but hasn't all this Intel beating news raised the hype? So many other tech companies are so severly overvalued and hyped daily. Why is AMD a steady 28-32?

It was below 3 in 2016.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#133
post #87
post #2

AMD is in a really good position right now. Intel still has the lead in low idle power which is good in laptops. Ryzen lets different cores have different max frequencies so if your code is single threaded and your operating system isn't the newest that could be a reason to go Intel. Likewise if its single threaded and can take advantage of AVX-512 or the Intel Math Kernel Library. But otherwise?

I think most server operators look at overall performance. Once you start buying hardware specifically for one purpose you're cornering yourself. Besides, who spends $15,000 on a mid-high end server to run single threaded applications anyway?

I would say most apps don't benefit from multiple cores. So single threaded performance is still important.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#134

I'm ignorant in stock trading, I admit. But I dont understand why AMD stock isn't blowing up. It's done a recovery after a market wide dip, but hasn't all this Intel beating news raised the hype? So many other tech companies are so severly overvalued and hyped daily. Why is AMD a steady 28-32?

It was below 3 in 2016.

This. I bought at $1.56 and sold at $29 for an unbelievably awesome trade. Will pick up more anytime it dips below $30.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#135
post #2

AMD is in a really good position right now. Intel still has the lead in low idle power which is good in laptops. Ryzen lets different cores have different max frequencies so if your code is single threaded and your operating system isn't the newest that could be a reason to go Intel. Likewise if its single threaded and can take advantage of AVX-512 or the Intel Math Kernel Library. But otherwise?

The main selling point for Intel isn't speed anymore. Intel still has superior performance counters and debugging features. Mozilla's rr (Record and Replay framework) only works on Intel for example, and Intel vTune is a very good tool. AVX512 is also an advantage, as you've noted. There are other instruction set advantages: I think Intel has faster division / modulus operator, and also has single-clock pext / pdep (…

>Mozilla's rr (Record and Replay framework) only works on Intel for example

Can you source that? I can't find it on the Wikipedia page[1] or its homepage[2].

[1]: https://en.wikipedia.org/w/index.php?title=Rr_(debugging)&ol... [2]: https://rr-project.org/

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#136

Earlier quoted context omitted.

The main selling point for Intel isn't speed anymore. Intel still has superior performance counters and debugging features. Mozilla's rr (Record and Replay framework) only works on Intel for example, and Intel vTune is a very good tool. AVX512 is also an advantage, as you've noted. There are other instruction set advantages: I think Intel has faster division / modulus operator, and also has single-clock pext / pdep (…

>Mozilla's rr (Record and Replay framework) only works on Intel for example Can you source that? I can't find it on the Wikipedia page[1] or its homepage[2]. [1]: https://en.wikipedia.org/w/index.php?title=Rr_(debugging)&ol... [2]: https://rr-project.org/

https://github.com/mozilla/rr/issues/2034

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#137
post #24
post #23

Earlier quoted context omitted.

The BLAS & Lapack subset of the API of the Intel Math Kernel Library (MKL) is very well implemented in open source projects such as OpenBLAS and BLIS: https://github.com/flame/blis Both are well optimized for AMD CPUs.

I work in this space... and let's just say that MKL is definitely NOT well optimized for AMD's chips. You'll be lucky to get 10-20% efficiency. Nevermind openblas.

I feel like at this point if you use an intel library or compiler you should know its Intel only. If you aren’t using it in a controlled environment stick to clang/gcc.

I can’t really blame them. Why support your competitor?

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#138
post #4

Why is AMD making these chips with 14nm transistors instead of using TSMC's 7nm stuff? AMD is only catching up to Intel because Intel's 10nm has been delayed so much, but if Intel can ever figure out their 10nm process they'll be in the lead again.

>if Intel can ever figure out their 10nm process they'll be in the lead again.

What are you basing this claim on?

All we know Zen2 targeted beating an hypothetical 10nm Intel CPU which has not shown up.

As it has not shown up, it remains hypothetical. Wild what-ifs.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#139

Earlier quoted context omitted.

Zen2 is 16MB L3 per ccx across the entire stack (hence why even the Ryzen 5 3600 is 32MB of L3 - it has 2 CCXs). There's no reason to assume this won't be true on Threadripper 3000. So a 32-core Threadripper 3000 would have at least 128MB of L3.

L2 cache is what matters. Zen2 has just 512 KiB per core. My old Pentium-M had 2MB. I wish modern CPUs had at least this much.

Performance is what matters, not cache size. Your Pentium-M didn't even have L3, hence why its L2 is so big.

Re: AMD Ryzen Threadripper 3000 32-core CPU is more bad news for Intel

#140
post #2

AMD is in a really good position right now. Intel still has the lead in low idle power which is good in laptops. Ryzen lets different cores have different max frequencies so if your code is single threaded and your operating system isn't the newest that could be a reason to go Intel. Likewise if its single threaded and can take advantage of AVX-512 or the Intel Math Kernel Library. But otherwise?

The main selling point for Intel isn't speed anymore. Intel still has superior performance counters and debugging features. Mozilla's rr (Record and Replay framework) only works on Intel for example, and Intel vTune is a very good tool. AVX512 is also an advantage, as you've noted. There are other instruction set advantages: I think Intel has faster division / modulus operator, and also has single-clock pext / pdep (…

[deleted]
Post reply on HN