Kioxia CM7-V with the ASRock TRX 50 Motherboard

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Hello!

I recently ordered some Kioxia CM7-Vs to pair with the ASRock TRX 50 (And the WRX 90 whenever it comes out). I saw a Tweak Town article about the CM7 mention that “Very short traces and/or signal boosters are required for PCIe Gen5 SSDs to operate reliably or even to initialize.”. Speaking with the author of the article, he said that plugging in the CM7 to the ASRock’s MCIO connector would not work.

After recently watching Wendell’s new video on the ASRock board, I was thrilled to see he was also using the CM7. Unfortunately, he doesn’t go into much detail about the setup and results. He did mention using a m.2 redriver, but I couldn’t find anything on the market. Is he plugging in the MCIO connector to the M.2 stick and skipping the onboard MCIO? Does the ASRock board have a built in redriver?

If anyone has any experience with these new Gen 5 Enterprise drives (Or even Wendell!), I would greatly appreciate if you could provide more info on the proper setup of using the CM7 with the ASRock TRX50.

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yes, you need a redriver

the good news is that there are cables that have built-in redrivers now, including cables for that asrock mcio connector. the lead time for these cables is long, and I don’t have any that weren’t hand made for me, basically, yet.

this website is generally pretty reliable:
https://www.serialcables.com/product-category/gen5-edsff-adapters/

and gen5 m.2 to edsff, then gen5 edsff to u.2 but I dont see them from that vendor at this exact moment.

soon ™

p.s. the serial cables 38 pin mcio to u.2 from sc may not be the type that I have in mind, I have one on the way to test. the sample I have has the electronics literally built in the connector, its wild

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Hey Wendell,

Anymore news on the Gen 5 MCIO to U.2, cannot find built in redriver models anywhere (any links please?)

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First batch of 100, 38 failed qc, and another 20 were borderline (move cable, bus errors). Working on test batch 2.

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Another option to consider:
Higher end motherboards have started baking in PCIe redrivers to the MB itself so that normal passive cables can be used:

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image1276×1676 178 KB

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This was true on a lot of boards but is also misleading. I.e. the slimsas redrivers on the older sp3 boards was insufficient.

Also true that gen3 pcie cards still don’t work for gen4 devices consistently even though theoretically it should.

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Were the redrivers on the sp3 slimsas boards tunable?

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Meh :frowning:

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Yeah via bios options but even the auto train has a pretty wide range typically. At max strength the farthest slots are typically still barely in spec

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We have our own Redriver cards, really interested to use the onboard to keep slots free for GPU’s.

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oh dang, didn’t realize it had already been done with not the greatest success.

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Good point, the bios tunables seem to only be for the normal PCIe slots as opposed to the MCIO connectors.

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Neither the TRX50 or WRX90 have tun-able MCIO annoyingly (Well Asrock as far as I have tested here)

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If it helps anyone also Samsung M321RAGA0B20-CWK 128GB 4800 dimms are working well on both TRX50/WRX90 Asrock and GB Aero D (fully populated)

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ASRock trx50 is tunable but only level1/2/3 for the MCIo. Can take a pic later

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Really, I didnt see that, where abouts Wendell? It maybe hidden away on the WRX90 also

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Ah found it, thats def hidden lol

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For those interested, I have a gen 5 16x (4x4x4x4) MCIO retimer host prototype coming in, not sure if the retimer latency will be a pain or not with the CM7 U.2, I’ll keep the thread updated with progress.

Asrock have confirmed to me that the MCIO ports on both the TRX50 and WRX90 have redrivers and that there can be problems with some cables cutting corners and not all terminals are wired, hence the drives will not even mount (similar to what I have seen) I also have some beta bios to check so will also report back with any findings there.

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that sounds like something I need too :smiley:

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Do you have any thoughts on retimer vs redriver, in GPU compute use cases I have measured the latency isn’t really a problem with retimers, just not sure on storage?