bust interface issue can't enable PCIe 3.0 x16

[Freacks]

Hello everyone
My specs:
cpu: ryzen 5 5600x
mb: asus rog strix b450 f gaming
gpu: rx 6700 saphire pulse
so I am facing an issue where I can't enable PCIe 3.0 x16! it only detect PCIe 3.0 x8 checked by AMD software and gpu-z
I tried resetting the bios settings and clearing the camos.. also tried changing the pcie settings on the bios settings to support the PCIe 3.0 x16 but still using PCIe 3.0 x16!
I tried DDU and installing the previous driver and the newest driver but same
I tried cleaning pins and checking cables but the same thing
is there any solution?

 

[eidairaman1]

Hello everyone
My specs:
cpu: ryzen 5 5600x
mb: asus rog strix b450 f gaming
gpu: rx 6700 saphire pulse
so I am facing an issue where I can't enable PCIe 3.0 x16! it only detect PCIe 3.0 x8 checked by AMD software and gpu-z
I tried resetting the bios settings and clearing the camos.. also tried changing the pcie settings on the bios settings to support the PCIe 3.0 x16 but still using PCIe 3.0 x16!
I tried DDU and installing the previous driver and the newest driver but same
I tried cleaning pins and checking cables but the same thing
is there any solution?

Yeah, please open your motherboard manual to page ix and read the info near the astrixes (*)

https://dlcdnets.asus.com/pub/ASUS/mb/SocketAM4/ROG_STRIX_B450_F_GAMING/E14401_ROG_STRIX_B450-F_GAMING_UM_WEB.pdf?model=ROG%20STRIX%20B450-F%20GAMING

Spoiler

this is why i loathe m.2

 

[Freacks]

I have two m.2 installed ... how to fix then?

 

[arbiter]

outside removing the m.2 drive from bottom slot there is really nothing you can do. Its gonna run at x8 which likely not gonna effect performance anyway. tpu has pci express scaling tests they do and on a RTX 4090 going from 16x to x8 3.0 only effected that at around 3%. Your card should be at most 1% to likely 0%.

 

[Ware]

a RTX 4090 going from 16x to x8 3.0 only effected that at around 3%. Your card should be at most 1% to likely 0%.

The 4090 shows from 3% to 6% loss going from 3.0x16 to 3.0x8, depending on resolution.
The 6600XT shows 1.2% to 2.2% loss, and the 6700 is probably closer to this than the 4090.

 

[eidairaman1]

I have two m.2 installed ... how to fix then?

*** When the M.2_2 is occupied by M.2 device, PCIe x16_1 will run at x8 mode.

So you remove that m.2 device , place that it in a pcie 4x capable adapter card, and place it in the
PCIe x16_3 slot.

Otherwise you step up to a B550 or X570 based motherboard.

 

[arbiter]

*** When the M.2_2 is occupied by M.2 device, PCIe x16_1 will run at x8 mode.

So you remove that m.2 device , place that it in a pcie 4x capable adapter card, and place it in the
PCIe x16_3 slot.

Otherwise you step up to a B550 or X570 based motherboard.

to note doing that means the m.2 drive if its nvme will only operate at pcie 2.0 x4 so cutting that performance in half.

 

[RJ]

Even on X870E, I have 5 m.2 slots but use only 2 internal m.2's, any more and I would lose x16 for the GPU. My GPU is pcie 3.0 so I need x16. I think on pcie 5.0 you can get away with x8 with negligible (if any) impact on GPU performance.
You can sidestep this limitation if you must have x16: AMD mandates 2 USB 4 ports on X870.

I use an external m.2 enclosure and run it via USB4, it maxes out at 5GB/s. My enclosure has an older onboard controller so I can't max out the USB4 throughput but enclosures with the new JHL9480 chip can. I think 5GB's is perfectly fine. As I said, my 4TB enclosure runs slower but it's still fast:

 

[Toothless]

x8 is fine. Leave it alone.

 

[Freacks]

I removed one of the m.2 device and I tested the GPU using ''heaven benchmark'' on both 3.0 x8 and 3.0 x16 and got this results ...
at that point in benchmark for the maximum fps its not that big deal only 4 fps difference ..but for the minimum fps its big difference! also in other areas
same power usage and same temperate ... ig if you are playing games it will make a difference right? I can't test games because one of the m.2 has the OS and the other has games on it so ..

 

[kapone32]

5.0X8 = 4.0x16 or 3.0x32. This is a huge nothing burger.

 

[ir_cow]

If your GPU Gen 3.0, you aren't losing much going to x8. Not nearly fast enough to saturated the of 16x.

AMD 6000 series is Gen 4.

 

[dgianstefani]

5.0X8 = 4.0x16 or 3.0x32. This is a huge nothing burger.

He's not on 5.0 though is he.

 

[kapone32]

He's not on 5.0 though is he.

No B450 is 3.0. He is still getting 8 lanes. It is obvious that he would get more performance by updating his MB.

 

[freeagent]

I am running at 4.0 x8 right now, games feel ok, folding is fine. The only thing that seems to notice a difference is R24, must be measuring theoreticals.

 

[dgianstefani]

No B450 is 3.0. He is still getting 8 lanes. It is obvious that he would get more performance by updating his MB.

So what was the point of your first post, considering he's not on 5.0?

 

[freeagent]

I think he was just saying that 5.0 x8 is like 4.0 x16 and so on, I hate speaking for others but that was my interpretation..

 

[ir_cow]

I have a 3090 Ti at 8x Gen4. Can't say there is a difference from 16x and I gained a Nmve slot.

 

[freeagent]

an't say there is a difference from 16x and I gained a Nmve slot.

Right? I have my Hyper M.2 installed with 2x NVME.. they are only 1TB drives.. but still moar is gooder.

 

[Macro Device]

to note doing that means the m.2 drive if its nvme will only operate at pcie 2.0 x4 so cutting that performance in half.

Which only matters if OP uses this SSD for 24/7 large data chunks transfer.

This is the best possible solution to this issue. Getting full 16 lanes will ensure stable frametimes. Unlike 4.0 @freeagent and @ir_cow are talking about, 3.0 at 8 lanes is lame in terms of stability in demanding games, this is actually a problem. I seriously recommend placing this SSD differently.