A simple question comparing GPU's

Talk about Hardware used for Deep Learning


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MattB
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A simple question comparing GPU's

Post by MattB »

I have two rigs running the same model with only slightly different settings. Both are i9 CPUs, exact same MB's, etc. The only difference is one has an RTX 3080 10GB and one has an RTX 3060 12GB.

Both units shows GPU VRAM utilized to about 80% roughly.
The unit with the 3080 shows little CPU usage but shows the GPU 3D running 50-60%
The unit with the 3060 shows CPU usage at 40-50% and no GPU 3D usage

I would have expected the 3060, with less CUDA cores, to have higher GPU usage, not zero. The only other difference I can think of, between 6 and 8 series, is nVidia Physx support. The 3080 runs the same model at a substantially higher speed, obviously. But I'm just curious why the difference in how the load is processed. I fully expected the 3060 GPU/3D to be maxed out.

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MaxHunter
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Re: A simple question comparing GPU's

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Question:. Are these running in the same machine, or separate rigs?

I'm running two 30 series in the same machine and noticing two separate wonky things. 1) Bryan said that a newer version of tensor is combining the memory of the two automatically but using only one GPU to process. 2) I'm also noticing wonky faceswap usage when turning off one of the GPUs through Faceswap depending on what process I'm using. As an example, if I turn off my 3090 during conversions, it actually appears to use my 3090. 🤷

I bring this up because maybe the answer is in the newer way tensor is using the GPU memory and how it's reporting to your OS.

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MattB
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Re: A simple question comparing GPU's

Post by MattB »

There are two totally separate computers.

It's working, so it's just curiosity on my part. But since I'm pondering dropping some coin on a computer specifically for training I'm very curious about the hardware aspects. That said I didn't realize if I put two cards in one computer nVidia would pool the memory! I have two 3060's, but since they don't support SLI I just assumed one got shelved. Maybe I'll put 'em both in one rig and, hopefully, get a 3060 with 24GB of VRam. Or maybe I'll burn out my PSU and get a visit from the fire department.

Hold my beer... I'm goin' in...

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MaxHunter
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Re: A simple question comparing GPU's

Post by MaxHunter »

:lol: ...beer held.

Here's what Bryan said...

viewtopic.php?p=8313#p8313

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MattB
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Re: A simple question comparing GPU's

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Well, I actually did blow up my computer installing two GPU's. But it wasn't the power load, it was the fact I'm a clumsy oaf. New PSU installed and mystery also solved. I had 'hardware accelerated GPU Scheduling" disabled. When enabled windows reports the "3D" setting for the GPU. I tested it on 10 and 11. It does not appear to affect performance in any way. I get the same EG/s whether it's enabled or disabled. And now I know the answer to the age-old question of "If I push just a little harder will this GPU pop into that motherboard slot?" The answer was "No."

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Re: A simple question comparing GPU's

Post by MaxHunter »

If it makes you feel any better, I blew out my Asus Maximus X motherboard when I installed my dual GPUs a couple months ago!!

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Re: A simple question comparing GPU's

Post by MattB »

I know it's wrong, but it kinda does make me feel better. ;)

I have another dumb question while I'm on a roll. Can I mix GPU versions? I have two spare cards. Though I don't expect a "performance boost" being able to pool the VRAM would be nice for running larger models. And I've never destroyed two motherboards in a single month before. Why not set a record?

nvidia 3080 10GB
nvidia 3060 12GB

Thoughts? I see a lot of folks pairing "like" GPU's but not using a "JBOD" sort of configuration.

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Re: A simple question comparing GPU's

Post by MaxHunter »

😆 The pain eventually subsides. 😆

I have a 3080ti and 3090.

You can absolutely do that, and Nvidia will pool the memory unless you specify through windows. However, that's where the help ends, and will only use one GPU to process.

Also, there are two side effects. The first being when you use multiple slots your PCIe speed will drop. So, if you're using a pcie5, it will become dual PCIe4s. If your motherboard is PCIe4, it will become a pcie3, etc. Also I noticed a slow down and I think there's a bottleneck when you do this.

Personally, I've gone into windows and locked my 3090 to anything associated with Faceswap, python, etc. It seems to limit the memory sharing, but let's me use my 3080ti for gaming with few constraints, except when converting. When converting my frame rate drops (Assassin's Creed Odyssey) from 90-ish to 10-20-ish frames.

Last edited by MaxHunter on Mon Feb 13, 2023 12:03 am, edited 2 times in total.
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MattB
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Re: A simple question comparing GPU's

Post by MattB »

Well, I gave in and bought a used workstation with two 3090's. The good news is I'll be able to heat my basement with it. The bad news is it leaves me with several mid-level GPU's with no computer to run them in. Maybe I'll donate them to other users here on the forums.

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