Dual RTX 3090's? Or single 4090?

Hey everyone, first post. And not a computer hardware genius by any means lol...

I'm getting a new PC built as soon as I make a few decisions. The main thing I am wondering is if I am better off running 2X 24GB RTX 3090's? Or running a single 24GB RTX 4090?

I do get into some some pretty render intensive activities quite often. Optical flow and speed warp are something I would use quite regularly for example.

I may start to play with some 8K footage as well.

Processor looks like it will be a 13th Gen i9-13900K and looks like I need 64GB RAM for my needs. But can go up to 128 if it would be worth my while?

Advice is appreciated, thanks in advance!

Been near a month no replies. But anyways, I ended up going with a single RTX 4090. Works awesome, super fast!

I looked into a lot of bench marks and the single 4090 beat dual 3090's in many cases especially in 3D rendering programs up to over 2 times faster at times. For Davinci Resolve dual 3090's edged out a single 4090 slightly, but not by much.

Still went with the single 4090 just due to that much less power consumption and heat. Happy with my decision.

A single 4090 also actually runs cooler than a single 3090 due to it does more work that much faster, so isn't running as long. People worried about the 4090 being hot due to it running at 450 up to 600 watts OC. But the opposite is actually true. My 4090 doesn't go higher than 62° running 100% full blast.

Dual GPU scaling in Resolve has always been mediocre at best

https://www.pugetsystems.com/labs/artic ... olveStudio

You made the right decision

I agree with Zeb. You made a good decision.
The only thing you might find is that 8k with several OFX applied might run your GPU memory full. I have a RTX A6000 with 48GB and when I was doing a complex node structure with 8k footage it used up to 39 GB of GPU memory during render.

Otherwise your 4090 is a super fast card and should make working a breeze.

From staff:

Resolve uses the GPU memory on every card it has in the system that is selected for Resolve use.

Generally it doesn't share memory to other cards.. lets not get into exceptions.
If you have a GPU in the system but its not selected in preferences, its just a waste of space.

If you have mis matched GPUs, the slowest GPU will define how fast the system can process.

If you have GPUs with difference memory capacity, the lowest capacity will define how big an image and the type of processing before its runs out of memory. The cards with extra memory waste that memory.

If you have a separate UI GPU, that's something we generally don't favor now, whereas we did 10 years ago.

If you have one more powerful and more memory GPU compared to a second, use the better one for the UI but not as UI only. It might make a little difference if the gpu performance is close.

One very powerful GPU with lots of RAM is better than two average GPUs, for many reasons....

Anyone who says multiple GPUs are a waste of time are picking a use case that doesn't need them, after all the large facilities that put 4 x 24GB GPUS in their system are spending that money for fun.

Most users will be happy with one good GPU.

All image processing is in GPU.

Some new GPUs, with the Resolve Studio version. also support compression and decompression in a hardware stage in the GPU.

GPU driver selection makes a big difference in reliability.

One thing to consider is that the 4090 has a considerably larger L2 cache. This really shows itself in noise reduction as it can fit more frames in the L2 before having to go to the VRAM. 6MB vs 72MB.

See here: https://blog.neatvideo.com/post/rtx4090

fow what BM stated throughout the years, a single more powerful GPU is preferable to multiple lesser ones.

Power and heat can also be a big factor. Heat will build up faster especially if you are using 2 GPUs with non-blower style fans. More heat means faster time to performance throttling.

Power and heat can also be a big factor. Heat will build up faster especially if you are using 2 GPUs with non-blower style fans. More heat means faster time to performance throttling.

I saw a video where the guy water cooled a 3090TI/FE, it was amazing... I might do that just for fun.... (and to free up a slot...)

let me find it....

Power and heat can also be a big factor. Heat will build up faster especially if you are using 2 GPUs with non-blower style fans. More heat means faster time to performance throttling.

I saw a video where the guy water cooled a 3090TI/FE, it was amazing... I might do that just for fun.... (and to free up a slot...)

let me find it....

Liquid cooling is awesome.

In my home system, I have a 3080ti liquid cooled but it is an AIO so I didn't need to learn to that.

I upgraded from dual 3090 to a single 4090.

Single 4090 is a faster/better Resolve experience vs the Dual 3090.

You can actually render Neat Video Reduction over 30 fps on 1080 projects with a 4090!

Power and heat can also be a big factor. Heat will build up faster especially if you are using 2 GPUs with non-blower style fans. More heat means faster time to performance throttling.

I saw a video where the guy water cooled a 3090TI/FE, it was amazing... I might do that just for fun.... (and to free up a slot...)

let me find it....

Liquid cooling is awesome.

In my home system, I have a 3080ti liquid cooled but it is an AIO so I didn't need to learn to that.

I'm not sure it's worth while watercooling. More crap to go wrong. Like I mentioned, the 4090 does actually run a bit cooler real world in some tests. I've ran mine 100% for over 3 hours and never got above 62°C. Fractal Torrent case cools very well. My 4090 is an Asus Tuf OC with tons of cooling.

I'm even cooling the Intel i13900 no problem with air cooling using Noctua Chromax. Noctuas actually cool better than many water coolers. Not all all water coolers, but a lot of them.

I'm not sure it's worth while watercooling. More crap to go wrong. Like I mentioned, the 4090 does actually run a bit cooler real world in some tests. I've ran mine 100% for over 3 hours and never got above 62°C. Fractal Torrent case cools very well. My 4090 is an Asus Tuf OC with tons of cooling.

I'm even cooling the Intel i13900 no problem with air cooling using Noctua Chromax. Noctuas actually cool better than many water coolers. Not all all water coolers, but a lot of them.

I have an mATX case and mobo. No air cooled 4090 was going to fix in my case. Too big (mostly too tall. I would not be able to close the side panel). The MSI 4090 AIO might fit but may not. I'm waiting if a smaller 4090 with 240mm radiator will appear.

I'm not sure it's worth while watercooling. More crap to go wrong. Like I mentioned, the 4090 does actually run a bit cooler real world in some tests. I've ran mine 100% for over 3 hours and never got above 62°C. Fractal Torrent case cools very well. My 4090 is an Asus Tuf OC with tons of cooling.

I'm even cooling the Intel i13900 no problem with air cooling using Noctua Chromax. Noctuas actually cool better than many water coolers. Not all all water coolers, but a lot of them.

I have an mATX case and mobo. No air cooled 4090 was going to fix in my case. Too big (mostly too tall. I would not be able to close the side panel). The MSI 4090 AIO might fit but may not. I'm waiting if a smaller 4090 with 240mm radiator will appear.

Yes you do need a pretty wide case. The connector makes it that much worse, although there are some 90° 3rd party options now. You definitely don't want to bend/strain the connectors to get the case closed as it has been one of the main causes of melted connectors along with people not plugging them in all the way.

Hey everyone, first post. And not a computer hardware genius by any means lol...

I'm getting a new PC built as soon as I make a few decisions. The main thing I am wondering is if I am better off running 2X 24GB RTX 3090's? Or running a single 24GB RTX 4090?

I do get into some some pretty render intensive activities quite often. Optical flow and speed warp are something I would use quite regularly for example.

I may start to play with some 8K footage as well.

Processor looks like it will be a 13th Gen i9-13900K and looks like I need 64GB RAM for my needs. But can go up to 128 if it would be worth my while?

Advice is appreciated, thanks in advance!

Tracking in Fusion can take more than 80GB like nothing... 24GB VRAM is not enough for Davinci anyway.. RTX4090 is slower than 2x 3080 in some operations. But I would rather take 1x RTX4090. For 2 way GPUs you need better entire system as motherboard, CPU (XEON, Threadrepear). And it cost so much more, than is better just upgrade every new RTX generation...