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AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

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Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#72
post #9

The real question for me with all these AMD releases, what's Intel gonna release? It's surprising to me that Apple didn't announce an AMD based Mac Pro-- the chip Intel gave them must really be something. Too bad though because there could be a lot more of them (eventual Mac Pros) out there I'm guessing if they were using these Rome chips.

It's probably not just the chip, Intel provides financial incentives for manufacturers who build products around their chips.

>Intel provides financial incentives for manufacturers who build products around their chips.

Yes, but I think the bigger picture, Apple needed Intel's iPhone modem for another year. May not be worth to damage the relationship, not to mention the design were likely finalise some time ago.

I would not be surprised if the Sale of Modem Business to Apple will include agreement to keep Intel CPU on Mac. ( For the time being )

And I am sure AMD should be aiming EPYC at the Datacenter usage of Apple, which is huge in itself, rather then the market of Mac Pro. Although Apple using AMD on Mac would be a pretty big statement to the rest of the market.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#73
post #3

64 cores but 128 with simultaneous multithreading. And in a 2C configuration, you get 256 threads. That is a beautiful thing.

Memories of Niagara falls

These threads have a lot more heft than the ones in Sun's T series.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#74
post #71

I'm curious if anyone knows about that image of the AMD cpu - it says on it: "DIFFUSED IN USA" What exactly does that mean? Given the next line is "MADE IN CHINA", it would seem like "DIFFUSED" should be "DESIGNED" - or does that word have a new meaning?

Diffusion is a step in manufacturing CPU dies. It generally refers to the following step: http://www.cpushack.com/EtchingWafers.html

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#75
post #71

I'm curious if anyone knows about that image of the AMD cpu - it says on it: "DIFFUSED IN USA" What exactly does that mean? Given the next line is "MADE IN CHINA", it would seem like "DIFFUSED" should be "DESIGNED" - or does that word have a new meaning?

IIUC, diffused is where the silicon wafer is created. For 14/12nm, that's the GloFo fab in New York.

Made is where it's attached to the substrate, packaged etc.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#76

The real question for me with all these AMD releases, what's Intel gonna release? It's surprising to me that Apple didn't announce an AMD based Mac Pro-- the chip Intel gave them must really be something. Too bad though because there could be a lot more of them (eventual Mac Pros) out there I'm guessing if they were using these Rome chips.

Apple is very invested in Thunderbolt 3 which AMD chips can't provide.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#77
post #55

Earlier quoted context omitted.

I believe these chips have Uniform Memory Access via a shared memory interface on the I/O die. Am I mistaken? Edit, just confirmed: >Thanks to this improved design, each chiplet can access the memory with equal latency. The multi-core beasts can support to 4TB of DDR4 memory per socket. https://www.tomshardware.com/news/amd-64-core-128-thread-7nm...

They exhibit NUMA because if chiplet0 wants a line of memory that is held by chiplet4, it has to go get it from chiplet4. So the degree of NUMA is improved from the previous generation, but it is still not UMA.

Generally caches aren't considered to be "memory" in this sense or otherwise every multi-core chip would be considered NUMA since they all have private caches. Instead you normally talk about an architecture being NUMA when cores have different access speeds to different parts of main memory, as when you need to get another socket to forward you information from a RAM bank. This is something that the OS generally has to be aware of in scheduling decisions, unlike caches which are automatically managed by hardware.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#78

What's stopping them from creating 1000 core cpus?

Yields are the main barrier to single pieces of silicon that big. You have a certain chance of getting a defect per square mm of you chip and as they get bigger the chance of a bad defect gets higher and yields go down. Often they'll occur in a place where you can just disable a core or bank of cache and still sell the chip but not always. So yield rates tend to go down as chips get bigger. Also larger chips make less efficient use of the wafer.

Economically, there aren't so many people looking for 1000 cores that it makes sense to put in the NRE to assemble a giant package to put all of that in versus just selling a system that can have multiple sockets. Cooling limits also make spreading out work across multiple sockets a better choice.

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#79

Earlier quoted context omitted.

Given the JavaScript performance of the shipping units intended for mobile use, which is eclipsing the best of Intel's offerings, it might be possible that the A14 or A15 iteration actually surpasses Intel's chips at x86-64 code as well when run through a Rosetta-like compatibility layer. What if the high-end chip was ARM? It's not just about raw speed, it's about how much performance you can squeeze out of a particu…

What would be awesome if instead of a Rosetta-like (or qemu-user-like) compatibility layer, the chip supported multiple ISAs natively. The only company that has the rights to do both ARMv8 and amd64 is.. AMD :)

That would be nice but NVidia got in legal trouble with x86 patents when they tried to do that with their Project Denver.

https://en.wikipedia.org/wiki/Project_Denver

Re: AMD EPYC “Rome” Server Processors to Feature 8 to 64 Cores

#80

What's stopping them from creating 1000 core cpus?

Is there a market need for 1000 cores running simultaniously that doesn't already need all the other supporting infra you get from a couple extra "full fat" servers each running 64 cores? Presumably if there is any need, it's currently being done by gpus
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