PCI 4.0 16x slot reported as a PCI 5.0 8x with the AMD 9070 XT Reaper GPU

[Teeinae]

I just saw that the MAG b650 tomahawk wifi (the one I have) has something called lighting PCIE 4.0 which supports 64 GB/s transfer. Maybe that's why the system gets confused and says it's PCIE 5.0 x16 since it's the same bandwidth, still means I have to re-plug my GPU, but that explains why a PCIE 4.0 x16 motherboard can support a PCIE 5.0 x16 bandwidth.

Edit:
The MSI Mag B650 Tomahawk boards use an SMT PCIe x16 CPU-connected slot, not a through-hole mount design as Gen1-4 used.
View attachment 390149This is an unnecessary implementation for strictly Gen3 and Gen4 connectivity.

Very clearly, at some point in time *after* the PCB was designed and laid out, MSI/AMD decided that B650 boards did not need Gen5 capability.
The board is 'built' to be capable of it. Also likely: multiple 'tier' boards, share the same base PCB layout.
[Tangential: ASrock's 'new' B650 X3D board, also has Gen5 x16, IIRC]

Yeah, I just noticed this too as I said in the post above xD They call it lighting gen 4.0 which basically is PCI 5.0. I am confused on why they just don't call it PCIE 5.0 if it's built to be capable of the same bandwidth but maybe I am missing something? Still tomorrow I will try to reseat the GPU and see if I get the full 16 lanes!

 

[Event Horizon]

I'm pretty sure the number of current lanes goes down when idle. Try running a benchmark at the same time.

 

[Blue4130]

I'm pretty sure the number of current lanes goes down when idle. Try running a benchmark at the same time.

The number of lanes does not go down, the gen speed does.

 

[Event Horizon]

The number of lanes does not go down, the gen speed does.

My bad, yes only the gen speed is changing. I must have remembered my previous card's behavior incorrectly.

 

[LabRat 891]

Yeah, I just noticed this too as I said in the post above xD They call it lighting gen 4.0 which basically is PCI 5.0. I am confused on why they just don't call it PCIE 5.0 if it's built to be capable of the same bandwidth but maybe I am missing something? Still tomorrow I will try to reseat the GPU and see if I get the full 16 lanes!

Mere marketing wankery, unfortunately.

MSI Lightning Gen 4 PCI-E is the latest and the fastest PCI-E data transfer solution with 64GB/s of unidirectional transfer bandwidth that has doubled compared to its previous generation. PCIe 4.0 maintains both backward and forward compatibility with older and newer specifications. Optimized by steel armor design and server grade PCB, you can enjoy next-gen devices without any compromise.

https://www.msi.com/Landing/amd-x570-motherboard

PCIe 4.0 has a 16 GT/s data rate, compared to its predecessor’s 8 GT/s. In addition, each PCIe 4.0 lane configuration supports double the bandwidth of PCIe 3.0, maxing out at 32 GB/s in a 16-lane slot, or 64 GB/s with bidirectional travel considered.

link

No, its regular old PCIe 4. Its just marketing

[SOLVED] - Is MSI’s Lightning PCIE-E 4 faster than regular PCI-E 4?

I‘m wondering if the PCI Express on MSI’s new X570 motherboard has a faster data transfer rate compared to any other regular motherboard with PCI-E 4. MSI seem to advertise it as “Lightning Gen 4 PCI-E” https://www.msi.com/Landing/amd-x570-motherboard

forums.tomshardware.com

 

[timsdf]

I think this is a SW reporting error rather than the CPU/SOC forcing a PCIE-4 MB into PCIE5 mode as you would also be able to add in a fully fledged PCIE-5 NVME drive and obtain full speed which I doubt you can, maybe should reach out to MSI if there is a rep registered on TPU to investigate further, though wouldn't be getting my hopes up thinking a PCIE-4 MB can just upgrade to PCIE-5, it's all speculation at best at this point, CPU-Z is still showing 32GT/s and I would trust CPU-Z reporting more than 3DMark

3dmark is a synthetic test which reports the used bandwidth.

55GT/s is basically 5.0 speed while 4.0 is 23GT/s. Speed increase from regular 4.0 is not speculation.

 

[LabRat 891]

3dmark is a synthetic test which reports the used bandwidth.

55GT/s is basically 5.0 speed while 4.0 is 23GT/s. Speed increase from regular 4.0 is not speculation.

Slight mixup but, your 3DMark PCIe bandwidth test result does still imply greater than Gen4x16 bandwidth.

For PCIe 4.0,
the bandwidth for a x1 slot is 1.969 GB/s;
the bandwidth for a x2 slot is 3.938 GB/s;
the bandwidth for a x4 slot is 7.877 GB/s;
the bandwidth for a x8 slot is 15.754 GB/s;
and the bandwidth for a x16 slot is 31.508 GB/s

Everything You Need to Know About PCIe 4.0

In this complete guide, learn everything you need to know about PCIe 4.0 motherboards, slots, speeds, expansion cards, and whether you should upgrade.

www.trentonsystems.com

addtn'l reading:

PCIe 5.0 and CXL: A Technical Breakdown for Naval Operations

Learn more about how PCIe 5.0 and CXL can enhance both virtualization and containerization, how they play a role in enhancing modern naval applications, and how Trenton's solutions can help.

www.trentonsystems.com

What is PCIe 5.0? Everything You Need to Know

Learn more about what PCIe 5.0 is, how it offers improvements over previous generations, and if an upgrade is warranted.

www.trentonsystems.com

 

[timsdf]

Slight mixup but, your 3DMark PCIe bandwidth test result does still imply greater than Gen4x16 bandwidth.

Those are normal results after overhead etc. in that test. it's usually ~15-20% less than specifications real speed.

 

[Epaminombas]

Is your motherboard BIOS up to date?

 

[Denver]

Conduct thorough performance testing and compare the results with those of other users using the same GPU. If no regression is observed, there seems to be no reason for concern.

 

[1s0pr0p4n0l]

Hello,

I had the same problem last week with my Gigabyte AORUS Radeon RX 9070 XT on a X670E motherboard .

solved by reseating the GPU

 

[LabRat 891]

Yeah, please try that, I think @LabRat 891's theory is correct, but more data is needed

I just got my Sapphire Pulse RX 9070 XT into my X570+5800X3D (Gen4 native SoC)

 

[gman794]

My MSI X670-P WIFI and MSI B650 Tomahawk are meant to be PCIe 4.0 max but they run at PCIe 5.0 speeds with my 9070XT. Here are some screenshot I took from GPU-Z, HWinfo and MSI B650 Tomahawk with a game running in the background. Notice the PCIe link speed.

 

[redeye]

*If* that's true, then OP probably needs to re-seat his card. -It's only handshaking 8-lanes.
(I don't think ASPM/PCIe power savings de-negotiates lanes, just clockspeed/generation?)

and make sure in is level wrt to the motherboard. ie, no sag.

My MSI X670-P WIFI and MSI B650 Tomahawk are meant to be PCIe 4.0 max but they run at PCIe 5.0 speeds with my 9070XT. Here are some screenshot I took from GPU-Z, HWinfo and MSI B650 Tomahawk with a game running in the background. Notice the PCIe link speed. View attachment 392292

in this case could you run the the 3dmark pcie bandwidt test, to confirm or deny the spec readout?

 

[gman794]

and make sure in is level wrt to the motherboard. ie, no sag.


in this case could you run the the 3dmark pcie bandwidt test, to confirm or deny the spec readout?

I scored 0 in PCI Express

AMD Ryzen 7 7800X3D, AMD Radeon RX 9070 XT x 1, 32768 MB, 64-bit Windows 11}

www.3dmark.com

 

[niklus]

It is definitely PCIE 5.0 on B650 Tomahawk but why is it hidden by MSI, I think no one knows

 

[LabRat 891]

It is definitely PCIE 5.0 on B650 Tomahawk but why is it hidden by MSI, I think no one knows

IMO:
AMD purposely and artificially limited Gen5 (mostly) for product-stack delineation
(similar to B450/x470 lacking Gen4, when B550A exists)

Since, AMD *makes* a better portion of the firmware, it's logical that AMD 'reversed' its own decision, and has Navi48 overriding NBIO,etc. settings, handshaking 5.0 (beyond the mobo's firmware limit).