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Is it nefarious marketing or just that a lower end CPU with 8 memory channels doesn't need a whizzbang memory controller to get the memory capacity/performance

Is it nefarious marketing or just that a lower end CPU with 8 memory channels doesn't need a whizzbang memory controller to get the memory capacity/performance it needs? Besides, doesn't the platinum version only go to 4800 MHz anyways? (split comment to separate topics)

adrian_b 3y ago
Decreasing the DDR5 transfer rate from 4800 MHz to 4400 MHz may provide a minuscule improvement in Intel's CPU die yields, supposing that their manufacturing process is bad and it barely allows to reach the standard 4800 MHz frequency, which might be justified as allowing lower prices for the low-end SKUs. The users certainly do not want such a speed reduction, especially taking into account that they will usually buy standard DDR5-4800 modules, which will never be used at the performance that they have been paid for. It is very unlikely that the manufacturing cost reduction due to a relaxed specification for the memory controller is important. Cutting whatever features they could in the cheap SKUs, to annoy the customers (like disabling instruction subsets, and in Sapphire Rapids disabling the accelerators), has been the MO of Intel already for decades.
- zamadatix 3y ago
  I'm not saying people directly want lower memory clocks rather I'm saying 4000/4400/4800 MHz doesn't seem to be a decision based on intentionally aiming to create upsell segmentation because 400 MHz of memory bandwidth on an 8 channel system is a completely irrelevant way to incentivize people while using lower quality binning and manufacturing to compete on price IS an incentive people in that range want, even if it comes at a minor cost in performance (that's the point of the low end SKUs!). E.g. Epyc segments memory performance in the Edge line by cutting the number of memory channels in HALF, the equivalent of dropping to 2400 MHz speed in a loaded server. Now there are other additional reasons that's actually attractive to buyers as well, namely the Edge class is expected to be lower power and driving 12 channels of high speed memory is counter to that goal, but it gives an idea of how miniscule 400 MHz of memory bandwidth is in terms of things that matter for low tier server performance. If anything I'd say that Epyc has support for 12 memory channels (win of the dedicated I/O die) is leaps and bounds more relevant. The Intel SKUs would need to run their 8 channels at 7200 MHz just to break even and here we are talking about 4400 MHz instead of 4800 MHz as a deciding reason to not buy an Intel server! Every manufacturer has the MO of artificially cutting features to segment things. Intel, AMD, Nvidia, Apple - all of them. Now maybe the folks at Intel marketing were smoking something funny that day and genuinely though this limitation would actually create incentive to go to a higher tier, who knows. Even then, why would that particular (poor) segmentation be a driver be worth choosing to exclude a brand over when the meaningful segments from all players are all much larger?
  - adrian_b 3y ago
    Except for Intel, the others, like AMD or NVIDIA, cut features that reduce the performance without having a software impact, and which indeed correspond to real reductions in the manufacturing cost, i.e. the number of cores, the size of the cache memories and the maximum clock frequencies. Only Intel has always disabled features that have negligible impact on the manufacturing cost, but which force various expenses upon the customers, like the disabling of various instructions or of internal peripherals. Due to this Intel policy, there are still plenty of programs that run slower than they should on the latest CPUs, because they may have been built for instruction sets that have become obsolete more than a decade ago, like SSE. The 10% memory throughput reduction is not negligible. There are 2 main scenarios for using a cheap Sapphire Rapids SKU, one would be to use it to host a very large number of SSDs, and the other would be to host some application that cannot be distributed over multiple servers and which wants a lot of memory. In the latter case, if the application has a performance dependent on the amount of memory, it is likely that it would also benefit from a faster memory, but with Sapphire Rapids if you want a 10% faster memory, which costs nothing extra in the price of the DIMMs, you may need to pay double or triple for the CPU.
    - zamadatix 3y ago
      I think you'd be surprised by how many identical style limitations others Nvidia has done over the years, from slightly lower clocked memory all the way down to programs that run slower than they should on other vendors because Nvidia code used by games was intentionally deoptimized for other platforms. AMD too, though to a lesser extent since it's been a while since it had its time in the sun from a market penetration perspective. 10% memory bandwidth is actually extremely negligible, particularly for the lower core count SKUs in the tier. The desktop gear you mentioned this all for has 1/3 the memory bandwidth, 1/4 if you plan on putting lots of RAM in, and can get away with a great deal many more tasks than you're describing something with 10% less memory bandwidth as able to do. We're talking a maximum worst case difference, for going between the lowest end Xeon to highest end Xeon, of 10% for the "my workload is to benchmark memory bandwidth only" use case. The reasoning for why it's supposed to be bad seems more focused with the starting assumption anything Intel does must somehow be bad than actually explaining what actual workload impact is had vs other options, and that's the red flag for me here.

adrian_b 3y ago

Decreasing the DDR5 transfer rate from 4800 MHz to 4400 MHz may provide a minuscule improvement in Intel's CPU die yields, supposing that their manufacturing process is bad and it barely allows to reach the standard 4800 MHz frequency, which might be justified as allowing lower prices for the low-end SKUs. The users certainly do not want such a speed reduction, especially taking into account that they will usually buy standard DDR5-4800 modules, which will never be used at the performance that they have been paid for. It is very unlikely that the manufacturing cost reduction due to a relaxed specification for the memory controller is important. Cutting whatever features they could in the cheap SKUs, to annoy the customers (like disabling instruction subsets, and in Sapphire Rapids disabling the accelerators), has been the MO of Intel already for decades.

zamadatix 3y ago
I'm not saying people directly want lower memory clocks rather I'm saying 4000/4400/4800 MHz doesn't seem to be a decision based on intentionally aiming to create upsell segmentation because 400 MHz of memory bandwidth on an 8 channel system is a completely irrelevant way to incentivize people while using lower quality binning and manufacturing to compete on price IS an incentive people in that range want, even if it comes at a minor cost in performance (that's the point of the low end SKUs!). E.g. Epyc segments memory performance in the Edge line by cutting the number of memory channels in HALF, the equivalent of dropping to 2400 MHz speed in a loaded server. Now there are other additional reasons that's actually attractive to buyers as well, namely the Edge class is expected to be lower power and driving 12 channels of high speed memory is counter to that goal, but it gives an idea of how miniscule 400 MHz of memory bandwidth is in terms of things that matter for low tier server performance. If anything I'd say that Epyc has support for 12 memory channels (win of the dedicated I/O die) is leaps and bounds more relevant. The Intel SKUs would need to run their 8 channels at 7200 MHz just to break even and here we are talking about 4400 MHz instead of 4800 MHz as a deciding reason to not buy an Intel server! Every manufacturer has the MO of artificially cutting features to segment things. Intel, AMD, Nvidia, Apple - all of them. Now maybe the folks at Intel marketing were smoking something funny that day and genuinely though this limitation would actually create incentive to go to a higher tier, who knows. Even then, why would that particular (poor) segmentation be a driver be worth choosing to exclude a brand over when the meaningful segments from all players are all much larger?
- adrian_b 3y ago
  Except for Intel, the others, like AMD or NVIDIA, cut features that reduce the performance without having a software impact, and which indeed correspond to real reductions in the manufacturing cost, i.e. the number of cores, the size of the cache memories and the maximum clock frequencies. Only Intel has always disabled features that have negligible impact on the manufacturing cost, but which force various expenses upon the customers, like the disabling of various instructions or of internal peripherals. Due to this Intel policy, there are still plenty of programs that run slower than they should on the latest CPUs, because they may have been built for instruction sets that have become obsolete more than a decade ago, like SSE. The 10% memory throughput reduction is not negligible. There are 2 main scenarios for using a cheap Sapphire Rapids SKU, one would be to use it to host a very large number of SSDs, and the other would be to host some application that cannot be distributed over multiple servers and which wants a lot of memory. In the latter case, if the application has a performance dependent on the amount of memory, it is likely that it would also benefit from a faster memory, but with Sapphire Rapids if you want a 10% faster memory, which costs nothing extra in the price of the DIMMs, you may need to pay double or triple for the CPU.
  - zamadatix 3y ago
    I think you'd be surprised by how many identical style limitations others Nvidia has done over the years, from slightly lower clocked memory all the way down to programs that run slower than they should on other vendors because Nvidia code used by games was intentionally deoptimized for other platforms. AMD too, though to a lesser extent since it's been a while since it had its time in the sun from a market penetration perspective. 10% memory bandwidth is actually extremely negligible, particularly for the lower core count SKUs in the tier. The desktop gear you mentioned this all for has 1/3 the memory bandwidth, 1/4 if you plan on putting lots of RAM in, and can get away with a great deal many more tasks than you're describing something with 10% less memory bandwidth as able to do. We're talking a maximum worst case difference, for going between the lowest end Xeon to highest end Xeon, of 10% for the "my workload is to benchmark memory bandwidth only" use case. The reasoning for why it's supposed to be bad seems more focused with the starting assumption anything Intel does must somehow be bad than actually explaining what actual workload impact is had vs other options, and that's the red flag for me here.