Building on their recent announcement of PCIe 5.0 retimers, Microchip has announced their first PCIe 5.0 switches, as part of their Switchtec PFX product line. On paper these look like a very straightforward update to their existing Switchtec PFX switches for PCIe 4.0, carrying over all the important features but doubling the speed.

The final version of the PCI Express 5.0 specification was released in May 2019, but significant adoption is not expected to begin until Intel's Sapphire Rapids Xeon processors ship, planned for later this year. Microchip is positioning themselves to be one of the most important vendors helping enable the transition, and they expect to be the only company offering both switches and retimers for PCIe 5.0. Components like switches and retimers are becoming increasingly important with each iteration of PCIe as higher speeds are achieved at the cost of range; servers using PCIe 5.0 will only be able to put a handful of devices close enough to the CPU to operate at PCIe 5.0 speeds without some kind of repeater. Retimers like Microchip's XpressConnect parts are simple pass-through repeaters, while switches like the new Switchtec PFX parts can fan out PCIe connectivity from one or more uplink ports to numerous downstream ports.

As with the PCIe 4.0 members of the Switchtec PFX product line, the new PCIe 5.0 switches will be available with lane counts from 28 to 100. These switches support port bifurcation down to x2 links, with bifurcation down to x1 supported by some of the lanes on the switch. The switches also support up to 48 Non-Transparent Bridges (NTBs), allowing for large multi-host PCIe fabrics to be assembled using several switches. However, initial demand for PCIe is expected to center around GPUs, machine learning accelerators and high-speed NICs, so many of those advanced features will be underutilized early on, and the chips will be primarily used to feed those extremely bandwidth-hungry peripherals with an x16 link each. SSDs using just two or four lanes each are expected to be slower about moving to PCIe 5.0.

The new PCIe 5.0 Switchtec PFX switches are currently sampling to select customers, including a development/evaluation board based around the 100-lane switch. Microchip wouldn't disclose any pricing information for the new switches, but they are bound to be more expensive than the PCIe gen4 switches with the same lane counts. Power consumption is also going up, but Microchip wouldn't quantify the change.

Microchip's lineup of PCIe switches for earlier generations also includes the Switchtec PSX and PAX families with more advanced functionality than the PFX switches. PCIe 5.0 versions of the PSX and PAX families have not been announced, but it's normal for those versions to come later. Microchip's only competition for leading-edge PCIe switches comes from Broadcom/PLX PEX switches. Broadcom has not yet publicly announced their PCIe 5.0 switches, but they are doubtless also planning to take advantage of the launch of Intel's Sapphire Rapids platform.

Source: Microchip

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  • onewingedangel - Wednesday, February 3, 2021 - link

    Both Sapphire Rapids and Alder Lake are 10nm, and should both release this year, but rate of ramp up is another question.
  • Deicidium369 - Wednesday, February 3, 2021 - link

    "vanilla" 10nm is Ice Lake and Ice Lake SP - ultra high volume
    10nm SF is Tiger Lake
    10nm ESF is the Golden Cove Trio and Xe HP and Xe HPC..

    So 3 different lines, Ice Lake SP is already in HVM and being shipped to OEMs - doesn't get much higher volume than a 2S Xeon.

    10nm ESF is later this year - and will be available in mass quantities - as it is a major long term platform (Golden Coves brings laptop, desktop and servers under same arch and bring 1-8S servers under the same arch - unlike Cooper Lake 14nm for 4-8S and Ice Lake SP 10nm for 1-2S)
    So volume will be a given - the AMD fanboy memes of Intel having terrible yields and performance are stale.
  • mode_13h - Friday, February 5, 2021 - link

    So much complaining about "AMD fanboys" and yet you always come to Intel's defense. Never a harsh word for them, as if they can do no wrong.

    I don't care why you do it, your actions speak for themselves. You're an Intel cheerleader, if not an outright superfan.
  • Qasar - Friday, February 5, 2021 - link

    mode_13h, thats what he does best. look at all the intel shilling he did last year. he claims to also buy amd, but considering how hard he shills for intel, i doubt that.
  • mode_13h - Friday, February 5, 2021 - link

    We should start referring to him as our resident Intel PR rep. Just to alert anyone who doesn't already know about his bias.
  • Deicidium369 - Wednesday, February 3, 2021 - link

    Yes - and Intel only ships in significant numbers - and not by the dozens like AMD....

    7nm was never going to be before 2023. Intel's 7nm is present in Xe HPC which was it's launch product anyway - that was delayed - but the Desktop (Meteor Lake) and Server (Granite Rapids) were never going to be much before 2023.

    Sapphire Rapids - late 2021 - and in late 2022 the 7nm follow up will be available...
  • RU482 - Wednesday, February 3, 2021 - link

    If Sapphire Rapids ships in 2021 I'll buy you lunch.
  • 29a - Wednesday, February 3, 2021 - link

    Do you really think you could stand being in the same room long enough to eat lunch, I couldn't?
  • calc76 - Wednesday, February 3, 2021 - link

    "7nm was never going to be before 2023."

    That's an interesting definition of 'never' as Intel publicly stated 10nm was expected by 2015 and 7nm by 2017.

    Intel should be at 3nm by now based on their own roadmaps from ~ 2013.

    Their 7 year fail is how we ended up with 14nm+++++++ Rocket Lake CPUs which run at 300W+
  • JayNor - Wednesday, February 10, 2021 - link

    xe-hpc is in the lab already. Some labeled die photos show Intel 7nm compute chiplets. Are these confirmed?

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