Hello, I hope everyone is well in these trying times!

I am learning to make infinite oceans with flip fluids for an animated short film project, which is challenging, I must admit!

I have 32 GB of memory in my current system, a rather old workstation limited to 32 GB, so I am thinking of getting a new system, because let’s face it, flip fluids take a lot of memory to be able to simulate good-looking simulations!

I have two questions…

1: How much ram should I get for my new system before it becomes too much, I know there is no such thing as too much memory for these types of simulations, but one needs to put limits at some point.

2: Should I get a RTX 3090 graphics card with 24 GB of VRAM for OpenCl acceleration, at the moment I only have 4 GB of VRAM and I top it most of the time.

I am posting an image showing the level of details I want for my simulations.

Thanks a bunch for any insight!

Gilles

No vfx artist ever said, I have to much memory. Buy as much as you can afford, if you're really into simulation a lot, I think 128Gb would be a good solid foundation.

Johan Boekhoven
No vfx artist ever said, I have to much memory. Buy as much as you can afford, if you're really into simulation a lot, I think 128Gb would be a good solid foundation.

Thanks for replying, I got a new AMD 16 cores CPU with 128 gb of ram, with room for an extra 128 gb if the need arise, so I guess I am set for fluids, those cache take a huge amount of space, so I build an array of hard drives as well, 14.6 tb in raid 1 + 0, should be enough for now, again, thanks for replying!

Just curious, what motherboard are you using?

eschwab
Just curious, what motherboard are you using?

An ASRock TRX40 CREATOR

Just a quick note that if you're running Windows, you need at least Win10 Pro to avoid the 64GB mem limitation in lower versions (like Home).

I've only built two computers so I'm by no means an expert. However I believe that the more ram you install in a motherboard, the slower the clock speed of the ram will be. However this doesn't matter if you can't run your sim at 64gb.

twod
Just a quick note that if you're running Windows, you need at least Win10 Pro to avoid the 64GB mem limitation in lower versions (like Home).

Yes, Home only supports 16GB of RAM, I am running Win10 Workstation, and the 128GB reads no problem, great tip though, so thanks!

eschwab
I've only built two computers so I'm by no means an expert. However I believe that the more ram you install in a motherboard, the slower the clock speed of the ram will be. However this doesn't matter if you can't run your sim at 64gb.

Depends on the CPU, the motherboard, and the ram you install, anything above 2933 mhz is OC ram anyway!

The trick is to go in the bios and set the ram at the highest speed possible, reboot, then test it for stability, eventualy you will find the sweet spot, mine tested fine ar 3600 mhz, no BSOD so far!

When doing FX, there really is no such thing as too much memory. Some problems get much easier to solve with more RAM, in particular anything related to volumes. It is true though, that once you are using many GB of RAM the clock speed of the chips start to become evident and it's not something to overlook.

jparker
When doing FX, there really is no such thing as too much memory. Some problems get much easier to solve with more RAM, in particular anything related to volumes. It is true though, that once you are using many GB of RAM the clock speed of the chips start to become evident and it's not something to overlook.

Thanks for the reply, at the moment I run 128GB at 3600MHZ and its stable, we'll see if I ever upgrade to 256GB, which seems a lot to be honest!

128Gb should be good for most detailed, large scale fx. However, if you are planning on working to deadlines on multiple shots simultaneously, 256Gb will allow you you keep several heavy scenes open at the same time.

One thing I'd say is that if you have a sim that needs something crazy like half a terabyte of RAM you're probably doing something wrong. I'd think that 64Gb is ok, 128Gb is sweet and anything above that luxurious. In a studio environment you'll probably not have that much available on the farm or get strange looks if you do. Splitting up your sim into different domains is likely a better solution anyway. If it is something that depends on a gpu you're probably limited by a much lower RAM ceiling.

jason_iversen
128Gb should be good for most detailed, large scale fx. However, if you are planning on working to deadlines on multiple shots simultaneously, 256Gb will allow you you keep several heavy scenes open at the same time.

I doubt that it will come to that, but I am glad that I kept room for an extra 128 GB, thanks!

Soothsayer
One thing I'd say is that if you have a sim that needs something crazy like half a terabyte of RAM you're probably doing something wrong. I'd think that 64Gb is ok, 128Gb is sweet and anything above that luxurious. In a studio environment you'll probably not have that much available on the farm or get strange looks if you do. Splitting up your sim into different domains is likely a better solution anyway. If it is something that depends on a gpu you're probably limited by a much lower RAM ceiling.

Thanks for you reply!

In the past I have done simulations that took all of my system ram to simulate (32 GB at the time), but took only a few GB to render, isn't the needed amount of memory needed to simulate and render two different things?

GCharb

Soothsayer
One thing I'd say is that if you have a sim that needs something crazy like half a terabyte of RAM you're probably doing something wrong. I'd think that 64Gb is ok, 128Gb is sweet and anything above that luxurious. In a studio environment you'll probably not have that much available on the farm or get strange looks if you do. Splitting up your sim into different domains is likely a better solution anyway. If it is something that depends on a gpu you're probably limited by a much lower RAM ceiling.

Thanks for you reply!

In the past I have done simulations that took all of my system ram to simulate (32 GB at the time), but took only a few GB to render, isn't the needed amount of memory needed to simulate and render two different things?

Yes, but the machines that do the work (simulation and render) are the same machines (at least they are in my experience).

jsmack
Yes, but the machines that do the work (simulation and render) are the same machines (at least they are in my experience).

My point is that it usually takes less ram to render than to do simulations, simulations are RAM hungry, Houdini is certainly no exception!

GCharb
In the past I have done simulations that took all of my system ram to simulate (32 GB at the time), but took only a few GB to render, isn't the needed amount of memory needed to simulate and render two different things?

Yes, that's not uncommon at all. Depending on the methodology employed, simulations have vastly different memory requirements, vastly different memory access patterns, and vastly different threading patterns. Sometimes it's a *lot* of heavy-lifting for a relatively small resultant mesh/volume.