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Does lightmass benefit from RAM or GPU

Hi all,

I understand lightmass is CPU bound, I am thinking about putting together a dual xeon light build machine (56 threads) for my office so I am looking into parts. Essentially one of our dev machines would be paired with this machine.

Our dev machines have 1080s and 32gb ram, can the light build machine be gpuless and have 4gb since the dev machines will also be contributing to the build or should the light build machine have something like 32gb and a gpu?

Product Version: UE 4.18
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asked Feb 23 '18 at 07:27 PM in Using UE4

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2 answers: sort voted first

from my experience there is a boost in performance by having a bigger gpu.

We use a little farm that build lights within the network, so adding computers is a great idea.

You can make a simple test and benchmark how long it takes to bake in a notebook and in a bigger computer the same little scene. You will find notebooks and desktop computers to share same ammount of ram usually, and that dont seem to be a factor for speed.

Difference could be found in your CPU though, i guess gpu vs cpu would be a propper question to ask. I bet that due to the architecture of unreal, gpu is the most important factor, but I dont know the details of light mass itself.

CPU could make a difference in speed, ram would only give you the limit of complexity you can handle.

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answered Feb 23 '18 at 09:59 PM

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avatar image axios714 Feb 23 '18 at 10:32 PM

From what I am reading, the gpu is only needed to export the initial process. Read that here: https://wiki.unrealengine.com/Swarm_Agent_Troubleshooting#.22Ran_out_of_Memory.22

I know CPU is the biggest factor, I am asking if I need to spend money on a gpu and ram for the new lightmass rig, or can the machine connected to it substitute the ram and gpu?

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lightmass doesn't share resources like that, you cannot have all your ram in one pc and all the cpu power in another, each node is independent of each other and just works on a small set of data from the whole. the default lightmass also does not use the gpu for calculations. Luoshuang has created a beta lightmass exe the does though.

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answered Apr 15 '18 at 08:02 AM

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