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Journeyman III
Journeyman III

PCIE 4.0

I recently upgraded my GPU and the Radeon software shows that it recognizes the PCIE 4.0 card but is running it at PCIE 3.0 bandwidth? I can not figure out why this is happening, or am I reading the Radeon system properties incorrectly? 

ASUS TUF x570 + wifi

Ryzen 7 3700x

Saphire 5700xt GPU 

Properties from Radeon Software:

GPU - AMD Radeon RX 5700 XT - Primary/Discrete
VRAM - 8176 MB - GDDR6 1750 MHz
Graphics Chipset - AMD Radeon RX 5700 XT
Bus Type - PCI Express 4.0
Current Bus Settings - PCI Express 3.0 x16  (Shouldn't this be 4.0?)
BIOS Version - 017.001.000.068
BIOS Part Number - 113-1E4260U-O4E
BIOS Date - 2020/04/07 01:59
Usable Memory Size - 8176 MB
Memory Type - GDDR6
Memory Clock - 1750 MHz
Core Clock - 1815 MHz
Total Memory Bandwidth - 448 GByte/s  (the online converter said this was 56GB/s, isn't pci 4.0 supposed to be 64GB/s?)
Memory Bit Rate - 14.00 Gbps
OpenGL® API Version - 4.6
OpenCL™ API Version - 2.0

Software Version  2020.0909.2058.37766

I tried to reinstall the software/ drivers, i even did a factory reset install of the radeon software, this did not change anything.  

I'm not sure what to do now?

3 Replies
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Miniboss
Miniboss

Re: PCIE 4.0

It should be 4.0 on a x570 board.

Check the PCIe settings in the bios.

Your not likely to see any real performance difference between the bus speeds.

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Adept I
Adept I

Re: PCIE 4.0

Maybe try GPU-Z to see how it reports it. Possibly, it's just a reporting error. GPU-Z has to put a load on your card to accurately identify the PCIe info.

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Journeyman III
Journeyman III

Re: PCIE 4.0


@ed_1234 wrote:


Total Memory Bandwidth - 448 GByte/s  (the online converter said this was 56GB/s, isn't pci 4.0 supposed to be 64GB/s?)


I think you are mixing some things here.

 

- 1 Byte has 8 Bits, GByte are typically abbreviated by "GB". That's why your conversion makes no sense, since 448 GByte/s are the same as 448 GB/s. You could instead convert it to GBit/s by multiply by 8.

- You're are reading the bandwidth of the VRAM (the memory on your VGA card). This has nothing to do with the bandwidth of your PCIe link.

- check your PCIe link status with GPU-Z tool. There is a question mark symbol next to the "Bus interface" box. Click that and then check the link status. Because of energy savings, the link speed will step down in idle. If its not showing 16x 4.0 while the small rendering test is running, you misconfigured something.

- In case you are using a vertical gpu mount, there is no PCIe 4.0 compatible riser cable available on the market. Any riser cable will max out at PCIe 3.0 bus interface speed. 

Fear not, for I am watchful.
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