A Neverending Story: PCIe 3.0/4.0/5.0 Bifurcation, Adapters, Switches, HBAs, Cables, NVMe Backplanes, Risers & Extensions - The Good, the Bad & the Ugly

A bit strange: Regarding pure SFF-8611-to-SFF-8611 (OCuLink) cables that vendor MicroSATACables seems to have two models that say they handle PCIe Gen4:

  1. With the part number OCU-1708-GEN4 (from your link) that’s higher priced

  2. With the part number OCU-1291-CBL but it’s quite a lot cheaper.

Am wondering if they mixed up PCIe 4.0 and SAS 4.0…

Interesting… I’d send them an email on that. They are very responsive when I’ve asked questions in the past.

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Will do and report back!

BTW Did you end up purchasing something from them? Haven’t used them as a cable source yet but the SLM-1775-M2 M.2-to-SFF-8654 adapter I got last year seems to have come from their eBay store.

(That M.2 adapter is annoying to use since its connector is facing the “wrong”, opposite direction to use it with most consumer motherboards and NVMe backplanes.)

MicroSATACable’s customer support guy is checking if these two models are the same or if there is maybe a listing error.

To be on the safe side I gobbled up their supply of OCU-1708-GEN4, at least the “GEN4” in the name is pretty clear so I’ll annoy their support if I again encounter these goddamn PCIe errors.

The first chain will be:

  1. Delock M.2 Key M to 1 x OCuLink SFF-8612 Converter

  2. MicroSATACable OCU-1708-GEN4

  3. Icy Dock ToughArmor MB699VP-B V2

Hope that shipping over the pond won’t take too long :-/

Still looking for a SFF-8654 4i to OcuLink SFF-8611 Gen4 cable.

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Micro sata cables actually tested a cable themselves when I asked them about it, here’s a reply I got via their ebay contact

As for this question, I would like to share with you what we checked here.
First of all, the cable we used is a silver plated 24G performance wire,
And we used Gigabyte PCIe Gen 4 mother board and Gen 4 SSD to test our cable.

For the time being, our Gen 4 SSD is about [email protected], [email protected] because we bought it 2 years ago.
We will buy new one for around [email protected], [email protected] SSD. But I think it also can reach to this R/W speed.

Because the cable performance is built on there.

Micro SATA Cables

Honestly it was great to see, and very helpful.

One thing I think may be happening is things just aren’t available, as the supply chain was disrupted and things which would normally be available on the typical sites to prosumers are being diverted to enterprise. When I recently looked for various ways to connect 4 nvme U.2 drives, I noticed a lot of things out of stock or requiring lead times, or almost impossible to find. I eventually found an ideal solution, but it took a while.

One very curious omission was the complete absence of a pciex16 4 port gen4 oculink adapter.

If good SFF-8654-to-SFF-8611 cables turn up this might be an option:


Somewhat strange development:

  • MicroSATACables’ support stated that they cannot supply an SFF-8654-to-SFF-8611 cable that can handle PCIe Gen4;

  • I personally am so used to manufacturers’ FAQs being useless that I had forgotten to check Icy Dock’s for the V2 OcuLink backplane and they state that a MicroSATACables SFF-8654 cable is to be compatible:

Known compatible cables:
Micro SATA Cables RML42-0503


I think these guys test without enabling PCIe Advanced Error Reporting in the BIOS or don’t know that only CPU PCIe lane errors get properly reported…? *


(*Regarding AM4/Ryzen 3000/5000 and X570)

Yay, the thingy arrived:

Now just the Gen4 OCuLink cables are the only thing missing, hope they also arrive soon.

What remains is that I’m pretty pissed at Icy Dock:

  • Me last year: Dear Icy Dock support, you state on your website that the MB699VP-B (V1) is PCIe Gen4-compatible. I’ve tried 3 units and not a single bay doesn’t produce PCIe transmission errors when it is actually running a Gen4 NVMe SSD, no errors up to PCIe Gen3.

  • Icy Dock support: Hey, that’s your cables’ or your motherboard’s fault.

  • Me last year: Well, can you tell me specific SFF-8643-to-SFF-8643 cables that can handle PCIe Gen4?

  • Icy Dock support: Yeah sorry, there are so many different HBA manufacturers, we can’t give any recommendations for cables.

  • Me last year: What does that have to do with a recommendation for a standard, non-proprietary* SFF-8643-to-SFF-8643 cable? Why don’t you offer cables yourselves where you can ensure the quality?

*(For example with Broadcom HBA 9400 models you have to use proprietary Broadcom SFF-8643 cables if you want to connect them to NVMe drives)

  • No further response

I generally like Icy Dock’s products and have been building many systems with them but that leaves a bitter aftertaste in my mouth :rage:

The label on the box pretty much clears it up that Icy Dock themselves don’t really consider the MB699VP-B (V1) to be PCIe Gen4-capable. I’d say this is close to false advertizing and while most text I write has ironic or sarcastic subtones I’m 100 % serial here…

I would really appreciate it if you would hold their feet to the fire a bit in any upcoming content with Icy Dock products.

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Funny you mention that, when I looked around their products, I also noticed the distinct omission of what cable to actually buy, and none provided by them. It’s definitely not an acceptable response.

…I wonder if there are any $15K Gen4 cable testers we could get Wendell to buy.

Yeah, I also left a comment with a question for such an SFF cable tester especially for PCIe Gen4 on the latest DisplayPort-themed video.



PCIe Gen4 seems to be becoming the Bane my existence… :sob:

UPS brought the MicroSATACables OCU-1708-GEN4, as giddy as a school girl I went testing the MB699VP-B V2 for the very first time with my Samsung PM1733 U.2 SSDs and got the worst results I have ever seen:

More than 10,000 PCIe bus errors in Gen4 mode over the course of a single CrystalDiskMark run with default settings :frowning:


In your first Icy Dock PCIe video at around 3:06 you state that the blue-ish wires indicate PCIe Gen3…
…and of course if you check through the cable shroud of the MicroSATACables OCU-1708-GEN4 you can see blue wires.

Could you explain the reasoning behind your"blue is bad" comment a bit?

thats just the stuff I’d ordered from ali express. I’ll take some pics at work tomorrow. The blue-ish cables always were bad.
the only ones that worked were silver.

That’s not hard and fast just me trying to spend my way out of my problems


Yeah, looks like I gave you bad advice, sorry about that.

I also got bit myself with the same issue. I picked up some of their ‌SlimSAS 8i to U.2 (SFF-8639) SSD dual port Adapters, and turns out they generate multiple correctable PCIe bus errors every minute that shows up in AER reporting even at just PCIe 3.0 speeds. Errors increase when any drives are attached. So I’ll be returning them shortly.

For reference, I had some M.2 boards (PCIe 3.0) from them that work perfectly fine with no errors.
Motherboard: TYAN® Computer - Motherboards S8030 S8030GM2NE
Cables: https://www.amazon.com/gp/product/B082NT2ZV9/
Working M.2 adapters: https://www.amazon.com/gp/product/B084GD4GKR/

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No worries, I had asked for sources, MicroSATACables’ item description looked good and of course it was ultimately my decision to order from them.


Have you had any configuration where you could use the MB699VP-B V2 without PCIe bus errors on a system where PCIe AER is confirmed to be working for the backplane’s PCIe lanes?

Since I don’t really know what avenues to pursue next there have not been any new new developments since the bad MicroSATACables OCuLink “Gen4” cables.


As an ambitious lay person regarding electronics (got a seperate soldering and hot air station, flux etc.) in the past I just followed instructions like Louis Rossmann’s videos to reflow bad SMDs but I wouldn’t know how to design HF signal traces like the 8 GHz lines that are needed for PCIe Gen4.

The only Gen4 part I could test without any issues are the most expensive Linkup PCIe Gen4 cable risers (with a 3060 and 3090), no PCIe Bus errors reported at all.

Now I’m thinking:

Can you use the tested-good wiring of such a PCIe Gen4 riser cable, remove its ends, design an M-Key M.2 PCB where the wires are placed in such a way that they are touching the motherboard’s M.2 slot pins directly on one end and on the other end attch a “premium” OCuLink connector?

I’m still refusing to give up on connecting a PCIe Gen4-capable U.2 backplane to regular M.2 slots, so hopefully maybe the signal integrity is good enough to not cause any PCIe Bus errors in a completely passive chain if you don’t have to use multiple adapters with the resulting signal losses from plugged connections.

Or is this more of a pipe dream?

I wasn’t able to find an oscilloscope that could handle 8 GHz to manually check signal quality so it would basically be just trial and error.

Ironically I had the least amount of PCIe Bus errors so far with the first-gen MB699VP-B with SFF-8643 connectors and “old” SAS3 SFF-8643 cables and an M.2-SFF-8643 adapter from Delock.

So I think we are pretty close to it working without PCIe Bus errors if the chain between the devices has less links and uses higher quality wires…

The next instrument of my suffering is on its way, a Broadcom P411W-32P
(Even though I’m kind of pissed at Broadcom)

  • A PCIe Gen4 x16-to-x32 (four SFF-8654 8i ports) switch add-on card without SAS or SATA functionality, so for the use with NVMe SSDs only;

Will be my first try with PCIe Gen4 over SFF-8654 8i to dual SFF-8643 or SFF-8611 (OCuLink)…

Broadcom_P411W-32P-UG104_PDF_Manual.zip (419.1 KB)


You got a good source for cables? Mine hasn’t planned out.

I have the 12th gen supermicro sp3 boards and one ASRock with the low profile pcie x8 . I need to order a full suite of cables to try various icy dock stuff.

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Unfortunately no new cable experiences (everything documented in this thread; ironically everything with SFF8611 OCuLink has been (far) worse than older SFF 8643 SAS HD cables).

For the Broadcom P411W-32P I just ordered two different generic kinds of cables for each type (SFF8654 8i to dual SFF 8611 OCuLink and SFF8654 8i to dual SFF8643) to get a general “feel” of SFF 8654 8i from Amazon Germany, at least here I have an easy way to get 100 % of my money back if the cables are shitty.

I fear that the Broadcom switch chipset won’t report any PCIe errors to the host, this was the standard behavior when using NVMe SSDs with the Broadcom HBA 9400 and Broadcom’s absurd 1 m long proprietary U.2 cables.

I still want to use 5.25" 4 x 2.5" U.2 backplanes with “consumer” M.2 or regular PCIe slot motherboards and I’m trying to get the knowledge how to build my own cables, to not have multiple adapted connections that reduce the signal quality.

I don’t get how people like Icy Dock or Micro SATA Cables aren’t ashamed of themselves. I honestly think they just plug a cable in, look if the device is connected via PCIe Gen4 and that’s their entire “qualification process”.

Also I was hoping that maybe you’d do a follow-up video with the guys from Liqid showing the physical connectors/adapters/cables that enable them to connect even PCIe Gen4 over distances.

I’m not married to the idea of using electrical copper wires for the cabling, if it is somehow “afordable” I wouldn’t mind getting suitable optical transceivers even if the cable length is less than 1m.

I HATE PCIe Bus errors :wink:

My prediction: You’ll just end up buying a 2U 24 bay U.2 EPYC server chassis that would have saved you money and suffering had you done that from the start.

NVME connectivity is such an expensive and proprietary shitshow.

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