I somewhat recently discovered the boards such as the Supermicro C9Z490-PGW and was wondering why there are not any modern versions. With the severe lack of proper HEDT and consumer CPUs reaching HEDT pricing and performance levels anyway, I’d be willing to try consumer socket with a switch — if they still existed. I mean I’d love to have Ryzen 7950X or Intel 14700K levels of performance instead of my E5-1660V3, but I simply cannot justify halving the amount of PCIE connectivity I currently have.
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Broadcom took over PLX technologies. That happened.
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What are you looking to connect?
Offhand, cpayne has a lot of interesting stuff, including PCIe 3 and 4 switches: PCIe Packet Switch Adapters - gen4 – C-Payne PCB Design
Be warned, advanced PCIe 4.0+ connectivity will either just work, or be a fractal pain in the ass of troubleshooting, begging vendors for bios updates (lmao good luck) and despair. Note you’ll likely want a redriver/retimer card, definitely send them an email before dropping cash on a dream here.
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Modern PCIe switches cause alot of issues with devices, they add non-trivial amounts of device latency that at times need to be accounted for in drivers and software.
Back in the PCIe 2.0 and maybe 3.0 days this wasn’t as big of a deal.
The dream of compossible infrastructure died when physics and data locality were encountered.
This is probably somewhat besides the point but I think Intel’s 4 channel HEDT platform would count as proper HEDT (proper meaning cheap). Between an entry level CPU and a motherboard you’d be in ~1100USD, I just bought a “comparable” AM5 motherboard and 7900 CPU for ~900USD.
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Funny thing is, there are actually pretty good PCIe switches available…
In the form of AMD X570 and B650 chipsets 
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Good luck obtaining those! 
Ultimately - I just want to be able to finally upgrade from my X99 system so I can move it over to being a NAS without giving up the I/O I have been accustomed to. I’d rather not go the switch route but the lack of HEDT options and Lite Workstation prices being double what HEDT used to be - I can’t justify that either.
I’m not looking to buy separate switches. Just trying to figure out why the obvious solution of pseudo HEDT died after Z490.
Say no more.
The cheapest (consumer available) CPU (12 core 2455X) for the W790 platform is over $1000 on it’s own plus another $800 for the motherboard and add in the registered memory tax so you’re looking at $2500 for the entry level base platform. All for a CPU that is slower than the top of the line consumer CPU that is almost half the price. So no, I don’t consider that Lite Workstation platform to be an HEDT replacement. Drop the price to like $750 for 12 or around $950 for 16 cores and release X790 that allows for cheaper boards with 48 lanes instead of 64 at a lower price and then we have HEDT again.
When I first heard rumors of LGA 1700 W chipsets I had really hoped that Intel had developed a north chipset that would take the 16 lanes of gen 5 and make 32 lanes of gen 4 available - but those boards were rather disappointing.
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Do you happen to know if the x16 slots downstream of the PCIe Switch chipset can be configured into x4 Bifurcation?
Obviously a motherboard’s UEFI wouldn’t have any effect here directly.
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Or if the firmware could be asked politely to bifurcate to some arbitrary width… 
Sorry, no idea.
The Microchip 40084 PCIe Switch used most certainly supports 1/2/4/8/16 bifurcation., and provides interfaces for onboard configuration.
CPayne’s other products will have connectors and accessories like USB-to-i2c adapters to configure just these things.
Ask CPayne!
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Quite a interesting turn of stories.
I have a 10th gen system (i7-10700 in Dell SFF), but being “computer enthusiast” I found myself really wanting to try out some IPMI. Also getting tired of SFF stuff, like “half height only” and “200W power 12VO supply” and the bad CPU temps.
I was looking for motherboards (with LGA 1200), but quickly realized most boards I came across will be completely useless for me.
I have a NVMe adapter card. It’s a x8 card, packet switch, goes to 4 m.2 drives. (no need for bifurcation). It’s not RAID, so it’s not exactly expensive.
I also have a (small, but not insignificant) GPU, between a T400 and a RX 550 (depend on which one they borrow), and might want another 4x m.2 carrier board.
The Dell SFF have an open-back x4 and a x16, so that’s how things went. But you need to actively try to find a board that have more than two slots that can accommodate x8 or x16 cards (most of them are closed backs, x1s)
The Dell SFF also have two onboard m.2, which I populate, and a wifi. Which is the most intriguing. That dinky OEM mATX board have more PCIe than like half of the boards I have seen. And those aren’t exactly cheap. Some of them make server boards look downright price-competitive, and that both seems and sounds absurd.
Even after the 6 NVMe drives I used up, I still have 5 more NVMe drives to use.
They are all 512GB variants, but I’m not looking for performance, either. I would happily buy another packet switch, but then I would actually run short of motherboard slots.
Buy Now Price, Any Quantity
1-24 US$617.85
25-99 US$513.52
100+ US$465.20
Never mind the price, notice the (profit) margins
(for those not familiar with manufacturer pricing, the quoted numbers are for each chip, not the entire lot!
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I think that answers the original question concisely. Price happened 
The price is more a symptom of the original problem, Broadcom. They did it with PLX chips and drive the market up like crazy and now they are doing it again with VMWare.
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I’ve heard this before from various outlets but it is simply not true, the w3-2423 can bought by normal consumers for ~400 (Newegg Business’s current price is 282 but I wouldn’t personally buy from them), I think what happened was that people assumed because the CPU couldn’t be bought in a normal retail box that it wasn’t available to consumers.
It’s up for debate if the CPU has strong enough core performance to be HEDT, but it definitely has the I/O to be HEDT, it doubles the memory bandwidth and increases PCIe bandwidth six fold over the 1660 v3.
Just want people reading this to know it’s an option, because it is often overlooked.
Yes, although to be more fair, motherboard OEMs aren’t going to be putting 84 lane PCIe switches on their motherboards, they’d probably put something with half the amount of PCIe lanes in.
If memory serves me right, the PLX8747 that motherboards use to use added a couple hundred dollars to the BOM.
Probably because Intel actively prevents the sale of tray CPUs and has for more than a decade. Basically - there’s a very valid historical reason for it.
Locked SKU - very firmly workstation and not HEDT - and also very firmly not for me because of it (and the fact I want a 12 to 16 core CPU to replace my 8 core).
I also have a hard time paying nearly twice as much for the motherboard as the CPU. That math just doesn’t work. lol I do get that there’s a market for it tho, I’m just not that market.
* barely audible exhortation, indiscernible from the whispering of your own thoughts *: do it
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pci switch is very simple. is anybody asking how the usb hub can pass multiple usb stick at same time ?? plx chip is same it do so by switching at way much more higher frequency than the bus itself… so it’s transparent, just like a usb hub or eth hub. But at gen4-5 and new cie aquisition… price did increased.