5 ms·

Is it the future of SoCs?

hajile 7y ago
Definitely. Intel has said they're going chiplet with some talk about 3D chips too. https://www.anandtech.com/show/14211/intels-interconnected-future-chipslets-emib-foveros https://www.anandtech.com/show/14211/intels-interconnected-f... Hotchips is full of chiplet talk. TSMC specifically calls out AMD, Xilinx, and Nvidia when talking about chiplets. https://www.anandtech.com/show/14770/hot-chips-31-keynote-day-2-dr-phillip-wong-vp-research-at-tsmc-145pm-pt https://www.anandtech.com/show/14770/hot-chips-31-keynote-da... Nvidia's Hotchips highlight is an AI accelerator with 36 chiplets on board (and interestingly, with a RISC-V controller -- probably the one they've been putting in their graphics cards). https://www.anandtech.com/show/14767/hot-chips-31-live-blogs-nvidia-multichip-ai-accelerator-at-128-tops https://www.anandtech.com/show/14767/hot-chips-31-live-blogs... A chip can't bin faster than its slowest core. Getting 28 cores that run at top speed is almost impossible (even with Intel's super-stable 14nm and many chip design iterations optimized for the process). In contrast, getting 8 cores at a high speed happens much more often. Likewise, a given manufacturing process is going to have an average of N errors per wafer. Duplication of parts of the chip can help, but they increase cost and some parts simply aren't economical to duplicate. If the error is in cache, you can probably laser off a cache block and move on. If the error is in the ALU, you probably aren't as lucky and will have to laser off an entire core (worse errors may even cut out an entire group of cores). A huge 28-core chip has a very high probability of an error meaning that you probably have a bunch of 26-27 core chips, but far fewer 28-core chips. What is the chances of finding that magic chip with 28 defect-free cores where all of them also run at high-speed? This is one reason why Intel has so many SKUs. AMD also sells the same chip to both consumer and server, so they can take the best of the best and ship them to servers. If there's a defective core or two, laser them out and sell one of those 12-core desktop parts. If it's missing a core and doesn't clock high enough, sell it as a 6-core 3-series chip. The ability to split fab nodes is also huge. Half of the new Zen 2 chip is 14nm. If they had to make that on 7nm as well, their supply would be halved and prices would go up substantially due to increased chip cost and decreased chip supply. If an interposer is needed, it can be even older (I think AMD used a 65nm for their Fury HBM interposer though something even older like 180nm would probably work just fine for wire-only interposers).
- wtallis 7y ago
  > A chip can't bin faster than its slowest core. Getting 28 cores that run at top speed is almost impossible Of note here is that Intel tried to identify which cores on a die could run fastest so that low thread count workloads could use only the best cores on the chip, but the software side was a disaster and they have pretty much given up on the concept. > AMD also sells the same chip to both consumer and server, so they can take the best of the best and ship them to servers. They may also be sending the most efficient chiplets to the server parts that have so many chiplets on each package, while keeping some of the fastest chiplets for the consumer parts. There's really not much precedent in recent generations for having one piece of silicon span such a wide range of products.
- wmf 7y ago
  A chip can't bin faster than its slowest core. Intel and AMD recently started binning individual cores, although I don't think it has hit Xeon yet.

Definitely. Intel has said they're going chiplet with some talk about 3D chips too. https://www.anandtech.com/show/14211/intels-interconnected-future-chipslets-emib-foveros https://www.anandtech.com/show/14211/intels-interconnected-f... Hotchips is full of chiplet talk. TSMC specifically calls out AMD, Xilinx, and Nvidia when talking about chiplets. https://www.anandtech.com/show/14770/hot-chips-31-keynote-day-2-dr-phillip-wong-vp-research-at-tsmc-145pm-pt https://www.anandtech.com/show/14770/hot-chips-31-keynote-da... Nvidia's Hotchips highlight is an AI accelerator with 36 chiplets on board (and interestingly, with a RISC-V controller -- probably the one they've been putting in their graphics cards). https://www.anandtech.com/show/14767/hot-chips-31-live-blogs-nvidia-multichip-ai-accelerator-at-128-tops https://www.anandtech.com/show/14767/hot-chips-31-live-blogs... A chip can't bin faster than its slowest core. Getting 28 cores that run at top speed is almost impossible (even with Intel's super-stable 14nm and many chip design iterations optimized for the process). In contrast, getting 8 cores at a high speed happens much more often. Likewise, a given manufacturing process is going to have an average of N errors per wafer. Duplication of parts of the chip can help, but they increase cost and some parts simply aren't economical to duplicate. If the error is in cache, you can probably laser off a cache block and move on. If the error is in the ALU, you probably aren't as lucky and will have to laser off an entire core (worse errors may even cut out an entire group of cores). A huge 28-core chip has a very high probability of an error meaning that you probably have a bunch of 26-27 core chips, but far fewer 28-core chips. What is the chances of finding that magic chip with 28 defect-free cores where all of them also run at high-speed? This is one reason why Intel has so many SKUs. AMD also sells the same chip to both consumer and server, so they can take the best of the best and ship them to servers. If there's a defective core or two, laser them out and sell one of those 12-core desktop parts. If it's missing a core and doesn't clock high enough, sell it as a 6-core 3-series chip. The ability to split fab nodes is also huge. Half of the new Zen 2 chip is 14nm. If they had to make that on 7nm as well, their supply would be halved and prices would go up substantially due to increased chip cost and decreased chip supply. If an interposer is needed, it can be even older (I think AMD used a 65nm for their Fury HBM interposer though something even older like 180nm would probably work just fine for wire-only interposers).

wtallis 7y ago
> A chip can't bin faster than its slowest core. Getting 28 cores that run at top speed is almost impossible Of note here is that Intel tried to identify which cores on a die could run fastest so that low thread count workloads could use only the best cores on the chip, but the software side was a disaster and they have pretty much given up on the concept. > AMD also sells the same chip to both consumer and server, so they can take the best of the best and ship them to servers. They may also be sending the most efficient chiplets to the server parts that have so many chiplets on each package, while keeping some of the fastest chiplets for the consumer parts. There's really not much precedent in recent generations for having one piece of silicon span such a wide range of products.
wmf 7y ago
A chip can't bin faster than its slowest core. Intel and AMD recently started binning individual cores, although I don't think it has hit Xeon yet.