F5F Stay Refreshed Hardware Desktop While browsing for a B550 motherboard, I discovered something I wanted to check...

While browsing for a B550 motherboard, I discovered something I wanted to check...

While browsing for a B550 motherboard, I discovered something I wanted to check...

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siggeking
Junior Member
1
10-30-2020, 11:21 AM
#1
Apparently some motherboards will throttle your PCI-E 4.0 GPU slot from x16 to x8 if you populate 2 or more of the M.2 slots. Not just with PCI-E 4 M.2's either, just one PCI-4 and one PCI-E 3 will cause the GPU slot to gimp. If this is true I think it needs to be more clearly pointed out in product descriptions, if this is nonsense then that too needs to be dealt with and squashed. Anyone know which way this goes for sure?
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siggeking
10-30-2020, 11:21 AM #1

Apparently some motherboards will throttle your PCI-E 4.0 GPU slot from x16 to x8 if you populate 2 or more of the M.2 slots. Not just with PCI-E 4 M.2's either, just one PCI-4 and one PCI-E 3 will cause the GPU slot to gimp. If this is true I think it needs to be more clearly pointed out in product descriptions, if this is nonsense then that too needs to be dealt with and squashed. Anyone know which way this goes for sure?

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LissieBear
Member
163
10-31-2020, 08:37 PM
#2
This depends on the particular board, and checking the detailed specs or manual will show you the PCIe layout on the board. PCIe Gen 3 and Gen 4 use identical lanes, so it shouldn’t affect how many lanes devices get. Switching from x8 to x16 for a GPU usually doesn’t create a noticeable impact either.
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LissieBear
10-31-2020, 08:37 PM #2

This depends on the particular board, and checking the detailed specs or manual will show you the PCIe layout on the board. PCIe Gen 3 and Gen 4 use identical lanes, so it shouldn’t affect how many lanes devices get. Switching from x8 to x16 for a GPU usually doesn’t create a noticeable impact either.

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tomoyan1441
Member
58
10-31-2020, 08:43 PM
#3
I believed it did. If it seems unimportant, maybe it's just a small marketing angle. Or could there be a real difference in FPS, even if it's barely noticeable?
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tomoyan1441
10-31-2020, 08:43 PM #3

I believed it did. If it seems unimportant, maybe it's just a small marketing angle. Or could there be a real difference in FPS, even if it's barely noticeable?

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mma0648
Junior Member
19
10-31-2020, 09:46 PM
#4
The gap between x8 and x16 is typically under 5% when using top-of-the-line chips, and most GPUs stay within the acceptable range. Displaying an x16 helps confirm compatibility, whereas an actual x8 slot usually won’t accommodate most GPUs.
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mma0648
10-31-2020, 09:46 PM #4

The gap between x8 and x16 is typically under 5% when using top-of-the-line chips, and most GPUs stay within the acceptable range. Displaying an x16 helps confirm compatibility, whereas an actual x8 slot usually won’t accommodate most GPUs.

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luxrox
Member
227
11-01-2020, 04:39 AM
#5
It raises questions about the performance of X570 boards compared to others. Still looking for the right one.
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luxrox
11-01-2020, 04:39 AM #5

It raises questions about the performance of X570 boards compared to others. Still looking for the right one.

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kahruu
Member
65
11-01-2020, 09:50 AM
#6
The situation varies by board. x570 offers numerous PCIe lanes from the chipset, which may ease concerns. What’s your complete build? I can assist once you share the remaining details.
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kahruu
11-01-2020, 09:50 AM #6

The situation varies by board. x570 offers numerous PCIe lanes from the chipset, which may ease concerns. What’s your complete build? I can assist once you share the remaining details.

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FatihTerim
Member
184
11-01-2020, 10:44 AM
#7
The deal stands at 4.0, which is double the speed of 3.0, and 3.0 is double the rate of 2.0. A 2080ti can barely exceed half of a 16x3.0 configuration, matching around 8x4.0—so you won’t be able to fully fill the bus even with a 3090 if it’s limited to x8. Advertising keeps moving forward. Cards are improving rapidly. If you shrink an x16 to an x8, you gain eight lanes free. An M.2 chip will consume only four slots, making it practical to double them both.
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FatihTerim
11-01-2020, 10:44 AM #7

The deal stands at 4.0, which is double the speed of 3.0, and 3.0 is double the rate of 2.0. A 2080ti can barely exceed half of a 16x3.0 configuration, matching around 8x4.0—so you won’t be able to fully fill the bus even with a 3090 if it’s limited to x8. Advertising keeps moving forward. Cards are improving rapidly. If you shrink an x16 to an x8, you gain eight lanes free. An M.2 chip will consume only four slots, making it practical to double them both.

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Allsky93
Junior Member
42
11-01-2020, 05:25 PM
#8
I also own an ASUS TUF Plus, but I suspect it's no longer functional. I purchased most of these components about ten months ago, intending to install them in November or December when the new GPUs were released, but we’ve seen that pattern before. I mistakenly left everything lying around until now, and the Mobo appears to have failed completely, so I’m starting anew. https://pcpartpicker.com/list/wDbXwz
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Allsky93
11-01-2020, 05:25 PM #8

I also own an ASUS TUF Plus, but I suspect it's no longer functional. I purchased most of these components about ten months ago, intending to install them in November or December when the new GPUs were released, but we’ve seen that pattern before. I mistakenly left everything lying around until now, and the Mobo appears to have failed completely, so I’m starting anew. https://pcpartpicker.com/list/wDbXwz

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CyberSubZero
Member
50
11-01-2020, 05:35 PM
#9
I think I'll go with x570. Usually it's not significantly pricier, and it lets you use two Gen 4 SSDs at full capacity, plus the GPU runs at x16.
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CyberSubZero
11-01-2020, 05:35 PM #9

I think I'll go with x570. Usually it's not significantly pricier, and it lets you use two Gen 4 SSDs at full capacity, plus the GPU runs at x16.

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CrazyBessyCat
Posting Freak
912
11-06-2020, 09:37 AM
#10
Remaining a challenging decision. It's difficult to locate them with a Type-C port on the front cover.
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CrazyBessyCat
11-06-2020, 09:37 AM #10

Remaining a challenging decision. It's difficult to locate them with a Type-C port on the front cover.

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