Advice please, single or dual graphics card?

Comments

• Elor Posts: 3,433

  January 7 edited January 7

  I don't think Iray is capable of pooling the VRAM of two recent 16 GB graphic cards to treat them as a single one with 32 GB so you'll be limited to 16 GB of VRAM, which mean any scene requiring more than 16 GB will render on CPU alone in a dual 16 GB GPU setup while a single 32 GB GPU setup will be able to tackle scenes requiring up to 32 GB of VRAM.

  For the flexibility offered by 32 GB alone, if my budget allowed me, I would get a 5090 instead of any of the alternative dual GPU setups.

  Regarding your questions:

  1. I think you should be able drop to 48 GB with a dual 16 GB GPU setup. 

  2. A 5090 did the benchmark in 45.72 seconds while a 5080 did it in 77.38 seconds, so a dual 5080 setup could be faster as long as a scene doesn't require more than 16 GB, but I don't think that possible difference is worth the flexibility offered by a 32 GB GPU.

  https://www.daz3d.com/forums/discussion/341041/daz-studio-iray-rendering-hardware-benchmarking/p47

  Post edited by Elor on January 7
• mikael-aronsson Posts: 599

  January 7

  Get the most VRAM solution (5090), if you use IRAY VRAM is more important than performance, modern DAZ characters use silly amounts of ram out of the box, and IRAY on CPU is as close to unusable as you can get.
• Cam Fox Posts: 326

  January 7 edited January 7

  Someone had a similar question middle of last year, added some thoughts here:

  https://www.daz3d.com/forums/discussion/comment/9327021/#Comment_9327021

  tldr; with multiple GPU's you'll have to account for additional cooling (they'll throttle if hot), case size and airflow, power requirements (both wall wiring and pc power supply need to be capable), and motherboard limitations (it'll limit bandwidth by half or more when too many devices share pci lanes)

  imo you would have the easiest time working with the single 5090 and it would be the most capable card for apps that aren't specially designed to work with separated cards' memory pool. If an app could only use one 5080, you could potentially end up in a situation where you only have half your pci bandwidth, half the vram (16 GB), half the cuda cores, half the tensor cores, half the memory bus. Put another way, a single 5090 covers all these bases without any special configuration.

  System RAM has no bearing on video card performance, but if you have too little of it, it might become a bottleneck for working with huge Daz scenes, running too many background apps, etc. RAM is where textures and data go before hitting the GPU's VRAM; if the system RAM is too low it'll use your disk (orders of magnitude slower). You can go with 48 GB system RAM and upgrade it later if needed. I wouldn't recommend less than 48 GB for a DS machine with a 32 GB 5090.

  Post edited by Cam Fox on January 7
• ArtAngel Posts: 2,030

  January 8

  Nvidia ended NV Link support back with RTX 4000. For my RTX 2080TIs (not all motherboards will accomodate it)  it was a Godsend. But irrelevant to 50s series.
• Stephano Posts: 33

  January 16

  Sorry for the late reply, but health issues have kept me offline 
• Stephano Posts: 33

  January 16

  Thank you all for your input, it supports what I was leaning towards, a single 5090. Prices in the UK are around the £2.2-2.7K mark, with 64Gb (2x32) RAM at £600-700, and 96Gb (2x48) at £1K+.

  I originally wanted to go with an AMD Threadripper 9960X, but that, the sTR5 motherboard and quad channel RAM would be around £3-4K. Instead I have decided to go with an AMD Ryzen 9 9950X3D, AM5 motherboard, and dual channel RAM for around £2K. In addition to the cost saving, the 9950X3D will draw less power and run at a lower temperature. A fully modular PSU, a pair of 1Tb M.2 SSDs for dual booting Linux and Windows 11, and a 2-4Tb HDD will round out the build, which should come in around the £4.5K mark.

  This rig is a retirement present to myself, and will most likely be the last one that I will be able to afford for a long time.
• csaa Posts: 953

  January 16

  Stephano said:

  Sorry for the late reply, but health issues have kept me offline 

  Stephano,

  Worth looking at this recent thread - https://www.daz3d.com/forums/discussion/753481/how-much-faster-is-it-to-render-an-image-in-daz-studio-if-you-have-two-gpus - Great minds think alike? 

   

  Cheers! 
• omvendt Posts: 102

  January 17

  I just went through the same thought process with help from the Daz hive mind. If one card does the job in 77 seconds, two cards will come in around twice as fast plus an estimated 12% penalty. That is not much faster than the RTX5090, so most def, go w the big bad card. I think 2x RTX4090 combo would look more attractive, since you'd have 24GB of VRAM on each card.