top PCIE running x8

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Aug 12, 2020
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this might seem silly to most of you but it's confusing me, i have a b450 gaming pro carbon with the latest f6 beta-bios, the top PCIE slot always seems to run at 8X instead of 16X is it to do with using the top M.2 slot
i've checked the bios and i can't set it to 16X it's either auto or 8X8 (plus gen 3 but figured won't be able to set gen 4 unless it's a B550)

ryzen 5 3600
M.2. 1GB
Red devil rx 6700XT
and another m.2 in the bottom M.2 slot.

thank you for any help
 

badboy2k

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as you have a Non G Processor that top slot should be running at full x16 speed.

the Top M.2 is coming Directly off the Last 4 PCI-E lanes of the CPU as it has 20 lanes so 16 for the top PCI-E slot and 4 for the top M.2 Slot and the Lower M.2 Slot is getting its lanes from the Chipset so noting should be making that top slot x8.

could you try Reseating your Graphics Card in the x16 slot to see if its just some dirt that is making it run at x8?
 

Alan J T

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this might seem silly to most of you but it's confusing me, i have a b450 gaming pro carbon with the latest f6 beta-bios, the top PCIE slot always seems to run at 8X instead of 16X is it to do with using the top M.2 slot
i've checked the bios and i can't set it to 16X it's either auto or 8X8 (plus gen 3 but figured won't be able to set gen 4 unless it's a B550)

ryzen 5 3600
M.2. 1GB
Red devil rx 6700XT
and another m.2 in the bottom M.2 slot.

thank you for any help
Are you using any of the other PCIE slots as the 6700 is a Gen 4 PCIEx16 card if you had the RX 6600 Gen4 PCIEx8 it would make sense but not a 6700 series card.
 

MegaGoat

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i have a 5600xt so that would be the same anyway. i've had no problems with the CPU but could that cause the situation ?
is it the standard cpu cooler that comes with the 3600 or somthing else? ive seen mounting pressure issues that cuse this its why i asked heh..
 

Alan J T

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i have a h115I pro uses the AMD bracket.
Yep I am going to say contact MSI support as well as Red devil
>>How to contact MSI.<<
It would be great if you could test GPU in a separate PC that is at least PCIE 3.0x16. 4.0 would be better but if GPU runs at PCIE 3.0x8 you will know it is the GPU at fault but if it runs at PCIE 3.0x16 you can suspect mother board or CPU problem
 
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seem's i havent been able to get hold of another board or GPU with X16.

i tried to switch the bios settings to 8X8 and was going to reset it to check if it "magically works" but it set itself to 2.1.1 was it supposed to happen even with not touching the gen bios tab.
 
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Alan J T

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seem's i havent been able to get hold of another board or GPU with X16.

i tried to switch the bios settings to 8X8 and was going to reset it to check if it "magically works" but it set itself to 2.1.1 was it supposed to happen even with not touching the gen bios tab.
Can you take a screen shot as you kind of lost me with the 2.1.1

I have mine set like this
1642125904815.png
 
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i also just bought a
MSI MPG B550 GAMING PLUS

do you think my adata ram will work. can't seem to find my type in ram support on the website.
 

Alan J T

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i reset it back to normal lol. when it's set on the X8 3.0 it stays the same when i put a load on it.
You want PCIE lanes on Auto you only change that if you have extra PCIE cards in use like 2 GPU on a Riser cable
 
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ahh, ok. i'm a newbie for stuff like this. thought it was something like that though. thank you for the advice.

now to wait for the new mobo and see it's really my gpu thats the problem lol
 

RemusM

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this might seem silly to most of you but it's confusing me, i have a b450 gaming pro carbon with the latest f6 beta-bios, the top PCIE slot always seems to run at 8X instead of 16X is it to do with using the top M.2 slot
i've checked the bios and i can't set it to 16X it's either auto or 8X8 (plus gen 3 but figured won't be able to set gen 4 unless it's a B550)

ryzen 5 3600
M.2. 1GB
Red devil rx 6700XT
and another m.2 in the bottom M.2 slot.
The motherboard (AMD B450 chipset) is PCI-E Gen3.
Your graphics card is PCI-E Gen4.
x8 Gen4 = x16 Gen3
 
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