Question Would a 2nd GPU plugged in a slot but not power supplied affect bandwidth?

[dlokx]

Hi,

I'm planning to build a new PC with an Nvidia 5000 series and and second GPU dedicated to PhysX, I intend to install them on an ROG CROSSHAIR X870E HERO motherboard and have read that using both GPU at the same time would cut the bandwidth by half. So the question is: would keeping the second GPU plugged in the PCIE slot while not connecting it to the power supply still affect the bandwidth?

 

[rgd1101]

what do you mean not connecting to power supply? the slot provide 75w.
and if you plug in a gpu that need additional power from pcie cable and not plug it from the psu. it will not function

 

[dlokx]

Well from what I understand using both GPU at the same time would cut the bandwidth of the first GPU by half even if the second GPU is not in use. Since the second GPU will only be used for PhysX when playing older games because the 5000 series doesn't support PhysX anymore. I won't be playing those games all the time so I thought that disabling the second GPU completely when not in use would lower the power consumption and be better for the performance of the main GPU. So I thought it would be less of a hassle to just have to plug the cable to the second GPU when I want to use it instead of reinstalling the GPU each time, especially since it appears that the PCIE slots of that motherboard tend to hurt the PCIE connectors of the GPU when trying to remove it. So I wondered if keeping the second GPU in the PCIE slot while not connecting the GPU to the power supply would still affect the bandwidth?

I don't know if I explained that a bit better English is not my native language.

 

[rgd1101]

unless you can disable it in bios, otherwise the motherboard will see it.

 

[kanewolf]

Hi,

I'm planning to build a new PC with an Nvidia 5000 series and and second GPU dedicated to PhysX, I intend to install them on an ROG CROSSHAIR X870E HERO motherboard and have read that using both GPU at the same time would cut the bandwidth by half. So the question is: would keeping the second GPU plugged in the PCIE slot while not connecting it to the power supply still affect the bandwidth?

It IS connected to the power supply via the PCIe bus. 75W power available from the bus.

 

[Zerk2012]

Well from what I understand using both GPU at the same time would cut the bandwidth of the first GPU by half even if the second GPU is not in use. Since the second GPU will only be used for PhysX when playing older games because the 5000 series doesn't support PhysX anymore. I won't be playing those games all the time so I thought that disabling the second GPU completely when not in use would lower the power consumption and be better for the performance of the main GPU. So I thought it would be less of a hassle to just have to plug the cable to the second GPU when I want to use it instead of reinstalling the GPU each time, especially since it appears that the PCIE slots of that motherboard tend to hurt the PCIE connectors of the GPU when trying to remove it. So I wondered if keeping the second GPU in the PCIE slot while not connecting the GPU to the power supply would still affect the bandwidth?

I don't know if I explained that a bit better English is not my native language.

Short answer is yes it would go to 8X8.


AMD Ryzen™ 9000 & 7000 Series Desktop Processors*
2 x PCIe 5.0 x16 slots with Q-Release Slim (supports x16 or x8/x8** or x8/x4/x4 modes***)
** When you use both PCIEX16_1 and PCIEX16_2, PCIEX16_1 and PCIEX16_2 will run x8.
*** When M.2_3 are enabled, PCIEX16_1 will run x8, and PCIEX16_2 will run x4.
**** When M.2_2 and M.2_3 are enabled simultaneously, PCIEX16_2 will be disabled.

 

[dlokx]

Thank you all for your answers, I understand a bit better and I apologize to be that dense, I was stuck on the idea that if there wasn't a cable connecting the GPU to the power supply the GPU wouldn't be alimented, my brain just couldn't register that the PCIE was also providing energy, sorry.