Specs advice for 4090 card

bobety316_c50224ad1f

I want to buy a pc with a 4090 card to work with daz. What are the reccomendations for specs for the pc to go alongside it?

Simply put as you can please! 

PerttiA

64GB's of RAM or more and a dedicated 4TB+ drive for the Content Library

dtrscbrutal

I always read the rule of thumb is at least 3 times the system memory of your GPU memory for Iray rendering. So you are looking at specing out 128GB of system RAM for your rig. It will definitely run on 64GB, but my understanding is you won't be getting max performance in Iray.

PerttiA

dtrscbrutal said:

I always read the rule of thumb is at least 3 times the system memory of your GPU memory for Iray rendering. So you are looking at specing out 128GB of system RAM for your rig. It will definitely run on 64GB, but my understanding is you won't be getting max performance in Iray.

It's not about performance, it's about the amount of RAM needed when preparing the scene for rendering (before it's sent to GPU)

If one is buying a 24GB card because the scenes one intends to make, do not fit in smaller ones, one also needs enough RAM to process the scene.
With the default Iray compression settings, 3 to 1 is pretty good estimate of how much RAM is needed.

dtrscbrutal

@PerttiA That is my understanding as well.

bobety316_c50224ad1f

Brilliant advice thanks. Do you think a 64g ram would be okay?

bobety316_c50224ad1f

PerttiA said:

64GB's of RAM or more and a dedicated 4TB+ drive for the Content Library

 

Excellent, thank you!

bobety316_c50224ad1f

dtrscbrutal said:

I always read the rule of thumb is at least 3 times the system memory of your GPU memory for Iray rendering. So you are looking at specing out 128GB of system RAM for your rig. It will definitely run on 64GB, but my understanding is you won't be getting max performance in Iray.

Thanks mate!

Petercat

3X RAM for a 4090 would be 72GB. I doubt if you'll see much difference between that and 64GB. 
I went from twin 3060's to a 3090 because my scenes were getting larger.
I had 64GB, and later added another 64GB. Haven't noticed a difference, feel like I wasted the money.
Yes, rendering a scene that used 22.3 GB of video ram, no appreciable difference.
Remember, that 3X is a suggestion, not a concrete rule.
Even that "3" is an approximation. What's the exact figure that gives best results? 2.9? 3.2? 2.7?
I would go with 64GB at first and keep an eye on your usage while rendering, with Task Manager.
Task Manager/Performance tab/memory

dtrscbrutal

 @bobety316_c50224ad1f I forgot they make 48GB x 2 memory kits for DDR5, another option. Also be sure to calculate your power needs and have enough power supply to run a 450 watt 4090 plus all of your other components.  

kyoto kid

Petercat said:

3X RAM for a 4090 would be 72GB. I doubt if you'll see much difference between that and 64GB. 
I went from twin 3060's to a 3090 because my scenes were getting larger.
I had 64GB, and later added another 64GB. Haven't noticed a difference, feel like I wasted the money.
Yes, rendering a scene that used 22.3 GB of video ram, no appreciable difference.
Remember, that 3X is a suggestion, not a concrete rule.
Even that "3" is an approximation. What's the exact figure that gives best results? 2.9? 3.2? 2.7?
I would go with 64GB at first and keep an eye on your usage while rendering, with Task Manager.
Task Manager/Performance tab/CPU1.

...it also depends on how much optimising you do as well.  A good thing to consider is "lower res" textures (MattyManx has released several such shader sets) for background items as well as instancing of you have multiples of a similar object in the scene.  There are number of other tricks to reduce the load on GPU and memory and still get decent quality images. 

The one thing you want to avoid is memory paging like when the process drops into "swap mode" (virtual memory).  Even of the GPU is capable to render the image that will also slow the process down  As I have old hardware with only 24 GB of system DDR2 triple channel memory and a 12 GB Titan-X. on a 2.9 GHz 6C/12T Xeon I still have renders that can take well over an hour just because of the memory limitation, particularly using mesh lights and other memory "heavy" elements.

Yeah bailing wire, chewing gum, and duct tape here. 

bobety316_c50224ad1f

Petercat said:

3X RAM for a 4090 would be 72GB. I doubt if you'll see much difference between that and 64GB. 
I went from twin 3060's to a 3090 because my scenes were getting larger.
I had 64GB, and later added another 64GB. Haven't noticed a difference, feel like I wasted the money.
Yes, rendering a scene that used 22.3 GB of video ram, no appreciable difference.
Remember, that 3X is a suggestion, not a concrete rule.
Even that "3" is an approximation. What's the exact figure that gives best results? 2.9? 3.2? 2.7?
I would go with 64GB at first and keep an eye on your usage while rendering, with Task Manager.
Task Manager/Performance tab/memory

Thats great, thank you

linvanchene

• Processor: Intel Core i9-13900K - max 5.80GHz - 24C
• GPU: ASUS ROG Strix GeForce RTX 4090 OC - 24GB
• RAM: 2x 32GB - Kingston Fury Beast RGB - LED
• Mainboard: ASUS ROG Maximus Z790 Hero
• Case: Corsair 7000D Airflow
• Cooling: Corsair iCUE H170i Elite XT / Corsair iCUE QL
• Powersupply: Seasonic Vertex GX 1200W
• Storage: Kingston KC3000 PCIe 4.0 NVMe M.2 SSD 4TB

 

This build was put together in March 2023 - no crashes, no issues so far.

You can replace some parts with more current equipment.

The most crucial parts are power supply and cooling - do not make any compromises there...