Question: How exactly does RAM impact on Render time and Capability?

[stevejjd]

Hi Guys

This is a question I have as part of my personal research; I am Planning to upgrade my computer to do Look Development on Characters and Props.

I have been using the V-Ray Benchmark Scores to help make a Price for Performance Graph and I'm building Workstation on Paper to compare.

I have a lack of understanding about how RAM effects the Speed and Capability of Rendering in V-Ray and I was about to deal with my ignorance by simply buying 128 GB DDR4 RAM. I got a shock at the price of RAM, so would like to know what tool I need for my job.

I aspire to be a professional 3D Character Artist who can Freelance for Blur Studio. So that means High Resolution Still Renders of Characters, Skin, Hair and Props. I don't think my current CPU is good enough given the modern expectations of content that can hold up in 4K let alone the future prospect of 8K. Also, Blur has very tight deadlines and making renderings as fast as possible will reduce stress and increase productivity.

So given that aspiration and goal of mine, how will RAM affect my computer build?

1. How does the amount of RAM affect Rendering performance ? for example 32GB vs 128GB
2. Do I need ECC RAM for this job?
3. Would 32 GB DDR4 be enough for the job?

Thanks again

Steve ~

[joconnell]

1. The danger is not having enough ram and tipping over in to virtual memory, then you're going to start seeing things grind to a halt. I don't know if you get a major performance benefit from ram but if you don't have enough, you're screwed!
2. No, if anything ecc is slower! Not all boards support it too.
3. Maybe. Texture res and displacement are going to be your major enemies so get used to turning everything into multires exr files for anything that's float and mip map tiff files for anything that's only 8 bit like colour and roughness maps. I'd go 64gb minimum for my next workstation.

[stevejjd]

Thank you so much for your help!

Question
- What is a Multi res .exr ?
- How to make a multires exr?
- What is mip Mapping?
- How to mip-map a .tiff

[glorybound]

ECC RAM might be slower, however, if you are going to render 24/7, isn't it a must?

[PIXELBOX_SRO]

I went for a total overkill for my machine with 256 GB of RAM and i have to say it saved my ass only once when i i did soem very heavy photoscanning (peak aroun 196 GB or so).
In heavier scenes i very often end up around 120.
So i woudl say go for 128, you wont regret it at all and make sure you still have space to add more as you go. The larger the mem size on one stick the better for you.
Scrap ECC its mostly for heavy duty servers

[stevejjd]

THanks for the advice @PIXELBOX_SRO

I didn't even know Windows Pro could accommodate that much ram. I thought it only went up to 128

[Ihno]

You can make multi res exrs using the image to tiled exr tool shipping with vray.
Mip mapping means the file contains the image in multiple resolutions (1024/512/265..) and the render engine picks the right one depending on the size of the texture on screen.
That helps to save ram and often also render time because vray won't get a different result every time it samples a pixel which for example would contain 200 tex pixels without mip mapping.
You gotta use the Vray HDRI loader then. The Max bitmap loader doesn't support mip mapping.

don't buy multible ram kits even though it might be cheaper.
https://rog.asus.com/forum/showthrea...atoes-overview
There is a big chance to get problems.

[stevejjd]

Thanks so much for that info Ihno