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

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

#81

Post by loeg »

kllrnohj wrote: post #78
loeg wrote: post #73

Earlier quoted context omitted.

Wait in what sense are the new Threadrippers no longer NUMA? Edit: Found the Zen 2 Epyc marketing materials that describe this. Yes, apparently memory access on a single socket is uniform, in that all memory access is indirected over the IO chiplet[1]! This may hurt best-case access latency for NUMA-aware workloads? Just speculating. It's not like non-local caches go away with uniform DRAM access latencies — unless L…

In the definition sense? It's a single memory controller on the IO die & one memory domain. The chiplets don't have their own memory controllers. By contrast Threadipper 1 & 2 had multiple memory controllers. It was 2x dual-channel controllers. As such they were full on real NUMA, just like a multi-processor system.

I was just looking for a source for the claim. Found my own pretty low-detail source; if you've got something better, I'd love to learn more.

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

#82

Post by [deleted] »

loeg wrote: post #76
FartyMcFarter wrote: post #72

Earlier quoted context omitted.

Which benchmark or comparison are you referring to?

Pretty much the only numbers in TFA: > The single-core score of 1,275 is pretty much the same as for the current flagship Threadripper 2990WX, ... > But when it comes to multi-core, the Threadripper 3000's score of 23,015 absolutely destroys the Threadripper 2990WX's score of 13,400, ...

[deleted]

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

#83

Post by dragontamer »

elheffe80 wrote: post #64

But what processor is best for Dwarf Fortress?

Dwarf Fortress is IIRC mainly limited by RAM latency. So you really should be trying to get 3600 MHz RAM with as tight timings (maybe CL16 timings?) as possible.

Dwarf Fortress's simulation is all about pointer-indirection and jumping around memory. The CPU doesn't really do much except wait for RAM most of the time. It takes ~50ns to talk to RAM, but the CPU is clocked at 4GHz (0.25 nanoseconds), giving you an idea of scale. The RAM tightening can bring your latency anywhere from 50ns to 200ns depending on how well you tune your RAM parameters, and depending on chips and stuff. (Servers usually have lots of slow LRDIMM RAM over multiple-sockets that can be 200ns latency or worse).

AMD takes their design out of the server-playbook, and seems to have ~100ns main DDR4 RAM Latency. So Dwarf Fortress probably will be faster on Intel i9-9900k (monolithic design with integrated memory controller and 50ns main memory latency).

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

#84

Post by znpy »

dragontamer wrote: post #25
Symmetry wrote: 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 (…

For the consumer market, this small advantages are not worth considering, imho. Amd processors do more and cost less, and power consumption is being optimised at each iteration.

For server/pro market they might be worth considering but again, the huge BOM cut that you get by choosing AMD processor might be worth the performance penalty.

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

#85

Post by bluecalm »

spamizbad wrote: post #50
rbanffy wrote: post #32

Earlier quoted context omitted.

That's true, but memory/IO is a much bigger issue in this scenario than processing power. While running a cluster in VMs, I'm frequently limited by IO (and if your VMs use more memory than it's physically available, you'll quickly descent into swap hell) well before my CPUs register a significant uptick in usage. And, mind you, my workstation is 4 year old Xeon with 64 gigs of memory and reasonably fast (but not amaz…

I really hope the 3000-series Threadripper is 8-channel like its server counterpart. 8 16GB DIMMs gets you 128GB, and a significant amount of memory bandwidth. You also have enough PCI-E lanes to either stripe or partition your I/O in such a way to work around any major bottlenecks.

My biggest hope is that you will be able to get 256 or 512GB of RAM with those. The biggest limitation for the previous one for me in comparison to Xeons was that you could only got 128GB of RAM.

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

#86

Post by paulmd »

loeg wrote: post #73
kllrnohj wrote: post #66

Earlier quoted context omitted.

The biggest upgrade over Threadripper 1950X is that the new ones are no longer NUMA. So performance across the cores will be much more consistent even if the peaks are not that much bigger. If your development involves compiling code then the 2x larger L3 is also going to result in huge improvements to code compilation speed as seen in the Epyc Rome reviews. Example: https://www.phoronix.com/scan.php?page=article&ite…

Wait in what sense are the new Threadrippers no longer NUMA? Edit: Found the Zen 2 Epyc marketing materials that describe this. Yes, apparently memory access on a single socket is uniform, in that all memory access is indirected over the IO chiplet[1]! This may hurt best-case access latency for NUMA-aware workloads? Just speculating. It's not like non-local caches go away with uniform DRAM access latencies — unless L…

Threadripper 1000/2000 (and corresponding Epyc) were true NUMA: each chiplet had IO for PCIe and memory onboard, and each die handled part of it. Thus you have "near" and "far" memory like a traditional NUMA.

On Zen2 everything goes through the IO die. In a sense this means everything is "far" now, but it is uniform, and performance seems to be very good despite this (perhaps due to the insane amount of cache meaning less need to hit memory as frequently).

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

#87

Post by zelon88 »

Symmetry wrote: 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?

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

#88

Post by paulmd »

loeg wrote: post #76
FartyMcFarter wrote: post #72

Earlier quoted context omitted.

Which benchmark or comparison are you referring to?

Pretty much the only numbers in TFA: > The single-core score of 1,275 is pretty much the same as for the current flagship Threadripper 2990WX, ... > But when it comes to multi-core, the Threadripper 3000's score of 23,015 absolutely destroys the Threadripper 2990WX's score of 13,400, ...

2990WX was a weird ultra-NUMA setup where half the dies had no direct memory access at all. Part of the gain will have been fixing that - particularly on Windows where the scheduler did not understand this configuration at all (Linux results have always been much better).

Another part is the power consumption and resulting higher clocks. The 2990WX was basically power limited, the new chips are on 7nm which will drastically reduce their power consumption and allow higher clocks inside the same power envelope.

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

#89

Post by DuskStar »

gameswithgo wrote: post #49
dragontamer wrote: post #10

Earlier quoted context omitted.

> I hear a lot about AVX-512 being really good. Its a great instruction set, Absolutely great, AVX512 supports gather/scatter, a whole slew of efficient processing instructions, etc. etc. However, AVX512 has poor implementations right now. Skylake-X is one of the only implementations, and running it drops the clock-rate in ways that are difficult to predict. (One core running AVX512 drops the clock of other cores, sl…

the clock rate has nothing to do with a bad implementation, all the computation just makes a lot of heat. the performance increase is still massive, often more than 2x avx, which also throttles btw

The clock rate issue isn't the fact that it downclocks a core when moving to AVX512, it's that it downclocked all the other cores on the processor at the same time.

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

#90

Post by Teknoman117 »

kllrnohj wrote: post #74
twotwotwo wrote: post #44

Worth noting AMD just announced that the first third-gen Threadripper will come out in Nov with 24 cores, and the planned 16-core mainstream chip (the 3950X) is delayed to November: https://www.tomshardware.com/news/amd-ryzen-9-3950x-delay-la... A 32-core chip is still almost certain to show up, since benchmarks have leaked, and folks have also leaked some pics of 3950X's and packaging, but I guess supply/demand have…

> As the Tom's post notes, server and client chips use the same chiplets, so it could be that most of the higher-binned ones are going to server parts; some are higher-margin (7742 is almost $100/core, vs. 3950X under $50/core) The 7742 is the "halo" chip, though. Or was, rather, until the Epyc 7H12 was announced. Other Epycs have much lower $/core. For example the 24-core EPYC 7352 is $1350, making it $56/core. The…

They also get cheaper if you only buy the single socket versions (assuming you don't need dual socket). The 7702P (the single socket 64 core) is $4425, or $70/core.
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