NVMe active adapter for different PCIe versions?

GotNoRice

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I'm not sure that what I'm looking for actually exists, but I thought I would ask anyway.

Most of the fastest NVMe drives out there right now, such as the 980 Pro, etc, use only 4 PCIe lanes. Well a PCIe 4.0 4x slot has the same bandwidth as a PCIe 3.0 8x slot and a PCIe 2.0 16x slot.

There are plenty of motherboards out there that don't support PCIe 4.0, but have available PCIe 3.0/2.0 8x/16x slots with the exact same bandwidth.

Is there an adapter, that you could put in an 8x PCIe 3.0 slot, or a 16x PCIe 2.0 slot, and give you a PCIe 4.0 M.2 socket? If the bandwidth is the same, then it seems like this should be possible.

And on a related note, why are so many NVMe drives seemingly limited to 4 lanes anyway? It doesn't seem that impressive when you think of all the 10+ year old motherboards with extra, often unused 16x slots intended for SLI or Crossfire that already had the same bandwidth as a current PCIe 4.0 4x NVMe socket.
 
M.2 NVMe drives only do four lanes, cause there's not enough pins for anything more. There's 75 total pins for m.2, and a standard pci-e x4 uses 64 pins (32 on side A, and 32 on side B), x8 is 98. I mean, maybe you could make x5 or x6, but nothing supports anything other than power of two lanes, so that's not really an option.

As for a pci 3 x8 to pci 4 x4 adapter.... that's theoretically possible, but probably too expensive to make.
 

Those look like traditional passive adapters. They are great for simply adding more M.2 slots. I used one for a while in my X99/5820k system because it didn't have an M.2 slot. But with those adapters you are basically just plugging your M.2 drive into a PCIe slot, lane for lane. The card isn't actually doing anything. If I have a PCIe 4.0 x4 drive and I use it with one of those adapters in a PCIe 3.0 slot, my drive would then become limited to PCIe 3.0 x4 speeds (half the bandwidth of PCIe 4.0 x4).

I'm looking for an adapter card where I could potentially plug in a PCIe 4.0 x4 NVMe SSD, and then have the card interface with the system at PCIe 3.0 x8 speeds (which is the same bandwidth as PCIe 4.0 x4, thus no bottleneck). There would have to be some kind of translation circuity onboard to translate the PCIe 4.0 x4 to PCIe 3.0 x8 but I don't see why it wouldn't be possible.
 
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You're looking for an up-converter that takes 2k version N-1 lanes and transforms it into k version N lanes, right? As toast0 said, I imagine that it's possible in theory, but I've never heard of such a part. There would be almost no demand for it, and it surely wouldn't be a simple circuit.
 
Highpoint 7505. You didn't say it had to be cheap, right?
I don't think the 7505 does what OP wants. It is PCIe 3.0 compatible, but I don't see anything saying that it pairs 3.0 lanes to get 4.0 lanes. I suspect that if you stick the 7505 into a PCIe 3.0 slot, you get 3.0 speeds.
 
I don't think the 7505 does what OP wants. It is PCIe 3.0 compatible, but I don't see anything saying that it pairs 3.0 lanes to get 4.0 lanes. I suspect that if you stick the 7505 into a PCIe 3.0 slot, you get 3.0 speeds.

It doesn't need to "pair" anything, it uses an intelligent switch with buffering etc.
 
The way I read the OP's request is to get PCIe 4.0 bandwidth to a PCIe 4.0 device, out of double the number of PCIe 3.0 lanes. I don't see anywhere in the 7505 description where it says that it does that.
 
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