PCIE4 @ x8 mode for 2nd GPU?
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PCIE4 @ x8 mode for 2nd GPU?
I'm looking to double up my FAH GPUs, 2 in one rig. My X79 board has: 3 x PCI Express 3.0 x16 slots (PCIE1 @ x16 mode; PCIE3 @ x16 mode; PCIE4 @ x8 mode).
Will the PCIE4 @ x8 mode affect PPD for the GPU installed there?
Will the PCIE4 @ x8 mode affect PPD for the GPU installed there?
Folding rig:Supermicro X9DRD-7LN4F-JBOD | (2) Xeon E5-2670 | 128GB DDR3 ECC Registered
Install Folding@Home on Linux without Python dependancy issues
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Re: PCIE4 @ x8 mode for 2nd GPU?
It will. However, very minor.
Most GPUs will see a degradation at PCIE 3.0 x4, but PCIE 3.0 x8 usually runs fine (without much PPD loss; PCIE 3.0 x8 is about as fast as PCIE 4.0 x4).
So long your GPU accepts the PCIE 4.0 standard, you'll have to get something faster than an RTX 3090, to be bottlenecked by the PCIE 4.0 x8 bandwidth.
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Re: PCIE4 @ x8 mode for 2nd GPU?
Since PCIE4 @ x8 has the same throughput as PCIE3 @ x16 (what my machines and many other folders use) it shouldn't limit the speed at all. My NVIDIA Setting app shows I'm using 1% bandwidth.
Re: PCIE4 @ x8 mode for 2nd GPU?
Thanks for this, was wondering if this would be the case, my experience even on PCIE 3 at 8 the difference is noticeable but not huge, I think it those populating PCIE 3 x2 slots that were used for mining that suddenly see this critical drop.bikeaddict wrote: ↑Fri Apr 29, 2022 11:14 pm Since PCIE4 @ x8 has the same throughput as PCIE3 @ x16 (what my machines and many other folders use) it shouldn't limit the speed at all. My NVIDIA Setting app shows I'm using 1% bandwidth.
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Re: PCIE4 @ x8 mode for 2nd GPU?
MeeLee wrote: ↑Fri Apr 29, 2022 7:35 pmIt will. However, very minor.
Most GPUs will see a degradation at PCIE 3.0 x4, but PCIE 3.0 x8 usually runs fine (without much PPD loss; PCIE 3.0 x8 is about as fast as PCIE 4.0 x4).
So long your GPU accepts the PCIE 4.0 standard, you'll have to get something faster than an RTX 3090, to be bottlenecked by the PCIE 4.0 x8 bandwidth.
OK, thanks for defining this, if there were to be a significant impact on performance I would then have opted to run the GPUs in separate machines.bikeaddict wrote: ↑Fri Apr 29, 2022 11:14 pm Since PCIE4 @ x8 has the same throughput as PCIE3 @ x16 (what my machines and many other folders use) it shouldn't limit the speed at all. My NVIDIA Setting app shows I'm using 1% bandwidth.
Folding rig:Supermicro X9DRD-7LN4F-JBOD | (2) Xeon E5-2670 | 128GB DDR3 ECC Registered
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Re: PCIE4 @ x8 mode for 2nd GPU?
The biggest issue you may have is the thermal impact ... with two gpus in case the chances are the air flow will be impacted ... one or both gpus may potentially have thermal issues - either running hot or even getting to the point of thermally throttling.
Good airflow case with lots of fans and relatively low ambient temps you shouldn't have any issues but worth monitoring ... Cluttered case with minimal fans and you may have sub-optimal experiences.
Good airflow case with lots of fans and relatively low ambient temps you shouldn't have any issues but worth monitoring ... Cluttered case with minimal fans and you may have sub-optimal experiences.
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Re: PCIE4 @ x8 mode for 2nd GPU?
Yes, so physical spacing between the slots you're going to use on the motherboard may be important too. Even in a good case, if the cards are sandwiched together with millimeter clearance, they may be thermally throttled.
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Re: PCIE4 @ x8 mode for 2nd GPU?
I was concerned, even-though my new build has all kinds of air flow the case is a mid-tower, and I'm thinking two fire breathing GPUs running 24/7 would cause an excessive heat build-up all around. So, whenever my new PSU gets here I've decided to put the RTX 3060 in with my GTX 1080, which is housed in a roomier server case.Neil-B wrote: ↑Tue May 03, 2022 9:27 am The biggest issue you may have is the thermal impact ... with two gpus in case the chances are the air flow will be impacted ... one or both gpus may potentially have thermal issues - either running hot or even getting to the point of thermally throttling.
Good airflow case with lots of fans and relatively low ambient temps you shouldn't have any issues but worth monitoring ... Cluttered case with minimal fans and you may have sub-optimal experiences.
Folding rig:Supermicro X9DRD-7LN4F-JBOD | (2) Xeon E5-2670 | 128GB DDR3 ECC Registered
Install Folding@Home on Linux without Python dependancy issues
Install Folding@Home on Linux without Python dependancy issues
Re: PCIE4 @ x8 mode for 2nd GPU?
A good option is to get a high quality, 1 or 2 inch riser, that will allow the GPU to be mechanically mounted in a slot above or below the standard slot.Neil-B wrote: ↑Tue May 03, 2022 9:27 am The biggest issue you may have is the thermal impact ... with two gpus in case the chances are the air flow will be impacted ... one or both gpus may potentially have thermal issues - either running hot or even getting to the point of thermally throttling.
Good airflow case with lots of fans and relatively low ambient temps you shouldn't have any issues but worth monitoring ... Cluttered case with minimal fans and you may have sub-optimal experiences.
Re: PCIE4 @ x8 mode for 2nd GPU?
Thanks, addressing the thermal issues is my current undertaking.MeeLee wrote: ↑Wed May 04, 2022 12:22 amA good option is to get a high quality, 1 or 2 inch riser, that will allow the GPU to be mechanically mounted in a slot above or below the standard slot.Neil-B wrote: ↑Tue May 03, 2022 9:27 am The biggest issue you may have is the thermal impact ... with two gpus in case the chances are the air flow will be impacted ... one or both gpus may potentially have thermal issues - either running hot or even getting to the point of thermally throttling.
Good airflow case with lots of fans and relatively low ambient temps you shouldn't have any issues but worth monitoring ... Cluttered case with minimal fans and you may have sub-optimal experiences.
Folding rig:Supermicro X9DRD-7LN4F-JBOD | (2) Xeon E5-2670 | 128GB DDR3 ECC Registered
Install Folding@Home on Linux without Python dependancy issues
Install Folding@Home on Linux without Python dependancy issues