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Single-chip processors have reached their limits

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Re: Single-chip processors have reached their limits

#31

Post by hesdeadjim »

refulgentis wrote: post #20

I'm embarrassed to admit I still don't quite understand what a chiplet is, would be very grateful for your input here. If a thread can run on multiple chiplets then this is awesome and seems like a solution. If one thread == one chiplet, then*: - a chiplet is equivalent to a core, except with speedier connections to other cores? - this isn't a solution, we're 15 years into cores and single-threaded performance is sti…

A chiplet is a full-fledged CPU with many cores on it. The term is used when multiple of these chips are stitched together with a high speed interconnect and plugged into the single socket on your motherboard.

If you ripped the lid off a Ryzen "chip", you would see multiple CPU dies underneath for the high end models.

Re: Single-chip processors have reached their limits

#32

Post by thissiteb1lows »

WithinReason wrote: post #17
monocasa wrote: post #9

Earlier quoted context omitted.

Yeah, in the very general case, chip errors are a function of die area. Cutting a die into four pieces so that when an error occurs in manufacturing, you only throw out a quarter of the die area is becoming the right model for a lot of designs. Like all things chips, it's way more complicated than that, fractally, as you start digging in. Like AMD started down this road initially because of their contractual agreemen…

Their GPUs are likely to be multichip for the first time too with NAVI 31 (while Nvidia's next gen will still be single chip and likely fall behind AMD). It also seems like that the cache will be 6nm while the logic will be 5nm and bonded together with some new TSMC technology. At least that can be inferred from some leaks: https://www.tweaktown.com/news/84418/amd-rdna-3-gpu-engineer...

No post body was provided.

Re: Single-chip processors have reached their limits

#33

Post by headass »

2OEH8eoCRo0 wrote: post #16
Veliladon wrote: post #13

The M1 Ultra is fabricated as a single chip. The 12900K is fabricated as a single chip and is still a quarter the size of the M1 Ultra. Ryzen 3 puts 8 cores on a CCX instead of four because DDR memory controllers don't have infinite memory bandwidth (contrary to AMD's wishful nomenclature) and make shitty interconnects between banks of L3. Chiplets are valid strategies that are going to be used in the future but ther…

> The M1 Ultra is fabricated as a single chip. I'm curious how much the M1 Ultra costs. It's such a massive single piece of glass I'd guess it's $1,200+. If that's the case it doesn't make sense to compare the M1 Ultra to $500 CPUs from Intel and AMD.

also all the other shit that’s on the chip ram etc.

Re: Single-chip processors have reached their limits

#35

Post by mjreacher »

tempnow987 wrote: post #7

"Reached their limits" - I feel like I've heard this many many times before. Not that I doubt it, but just I've also been impressed with the ingenuity that folks come up with in this space.

Agreed. I would be wary of reaching fundamental limits set by physics although I don't think we're there yet.

"It would appear that we have reached the limits of what is possible to achieve with computer technology, although one should be careful with such statements, as they tend to sound pretty silly in five years."

- attributed to von Neumann, 1949.

Re: Single-chip processors have reached their limits

#36

Post by Dylan16807 »

nine_k wrote: post #30
Dylan16807 wrote: post #29

Earlier quoted context omitted.

> I'll add that many DRAM chips already do something like this, but ironically enough the re-routing mechanism adds complexity which is itself a source of problems, (be it manufacturing or design, such as broken timing promises) The best-performing solution there is probably software. Tell the OS about bad blocks and keep the hardware simple.

I think this is already implemented both in Linux and in Windows; you can tell the OS which RAM ranges are defective. Doing this from the chip side is not there yet, apparently. I wonder when will this be included in the DRAM feature list, if ever. I suspect that detecting defects from the RAM side is not trivial.

> I suspect that detecting defects from the RAM side is not trivial.

Factory testing or a basic self-test mode could easily find any parts that are flat-out broken. And as internal ECC rolls out as a standard feature, that could help find weaker rows over time.

Re: Single-chip processors have reached their limits

#37

Post by cma »

Veliladon wrote: post #13

The M1 Ultra is fabricated as a single chip. The 12900K is fabricated as a single chip and is still a quarter the size of the M1 Ultra. Ryzen 3 puts 8 cores on a CCX instead of four because DDR memory controllers don't have infinite memory bandwidth (contrary to AMD's wishful nomenclature) and make shitty interconnects between banks of L3. Chiplets are valid strategies that are going to be used in the future but ther…

M1 ultra is two chips with an interconnect between them I thought? Or is the interconnect already on die with them?

(Edit: sounds like it is two: "Apple said fusing the two M1 processors together required a custom-built package that uses a silicon interposer to make the connection between chips. " https://www.protocol.com/bulletins/apple-m1-ultra-chip )

Re: Single-chip processors have reached their limits

#38

Post by [deleted] »

refulgentis wrote: post #20

I'm embarrassed to admit I still don't quite understand what a chiplet is, would be very grateful for your input here. If a thread can run on multiple chiplets then this is awesome and seems like a solution. If one thread == one chiplet, then*: - a chiplet is equivalent to a core, except with speedier connections to other cores? - this isn't a solution, we're 15 years into cores and single-threaded performance is sti…

[deleted]

Re: Single-chip processors have reached their limits

#39

Post by gameswithgo »

headass wrote: post #33
2OEH8eoCRo0 wrote: post #16

Earlier quoted context omitted.

> The M1 Ultra is fabricated as a single chip. I'm curious how much the M1 Ultra costs. It's such a massive single piece of glass I'd guess it's $1,200+. If that's the case it doesn't make sense to compare the M1 Ultra to $500 CPUs from Intel and AMD.

also all the other shit that’s on the chip ram etc.

It is commonly said that on the new M1 macs, that the ram is on the chip, it is not. It is on the same substrate, but its just normal (fast) dram chips soldered on nearby.
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