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Xanderman

macrumors newbie
Original poster
Nov 4, 2019
2
0
Greetings All. Just purchased a 2019 i9 iMac with the Vega 48 video card. Will upgrade the ram from 8gb to 64GB or maybe more. I'll use the machine for video work, lots of image editing in Lightroom, and architectural renderings using lumion which I will run from windows in boot camp. I'm leaning towards buying 2x32gb for 64gb total. This will leave 2 dims open so I can add 64 more in the future (total 128gb). I'd probably also keep the existing 4gbs in their slots which would give me 72gb total ram. Here are my questions:

1. Has anybody done this?
2. Are there any potential pitfalls mixing 32gb with 8gb? I assume no given that others have made this work with 16gb and the 8gbs.
2. At 64gb ram are there any performance reasons to choose 4x16gb over 2x32gb?
3. The machine has eight cores. Somewhere I read that a good rule of thumb for video editing is 4gb of ram per core and that anything more provides very little gain in performance. Is this true? If this is the case then even 32gb ram would be appropriate and 128gb would just be ridiculous overkill???

Thanks much for any and all feedback!
 

MacManiac76

macrumors 68000
Apr 21, 2007
1,646
422
White Mntns, Arizona
Since the system has dual channel memory, there will not be any advantage to using 4x16 GB over 2x32 GB. I would put the 2x32 GB in if it were me to leave room for future upgrades without having to sacrifice any of the newly installed RAM. You should be able to install the original 2x4 GB with the new 2x32 GB without any performance hit as long as you install them in the correct slots. Simply install the new RAM in the two empty slots and you will be fine. Not sure about your question about how much RAM should be sufficient for video editing as I really don't do any myself.
 
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Zdigital2015

macrumors 68040
Jul 14, 2015
3,199
3,956
East Coast, United States
Greetings All. Just purchased a 2019 i9 iMac with the Vega 48 video card. Will upgrade the ram from 8gb to 64GB or maybe more. I'll use the machine for video work, lots of image editing in Lightroom, and architectural renderings using lumion which I will run from windows in boot camp. I'm leaning towards buying 2x32gb for 64gb total. This will leave 2 dims open so I can add 64 more in the future (total 128gb). I'd probably also keep the existing 4gbs in their slots which would give me 72gb total ram. Here are my questions:

1. Has anybody done this?
2. Are there any potential pitfalls mixing 32gb with 8gb? I assume no given that others have made this work with 16gb and the 8gbs.
2. At 64gb ram are there any performance reasons to choose 4x16gb over 2x32gb?
3. The machine has eight cores. Somewhere I read that a good rule of thumb for video editing is 4gb of ram per core and that anything more provides very little gain in performance. Is this true? If this is the case then even 32gb ram would be appropriate and 128gb would just be ridiculous overkill???

Thanks much for any and all feedback!

I have a refurb i9/1TB SSD/Vega 48 and moved from 8GB DRAM to 40GB DRAM.

EDIT: Removed memory channel info as I was incorrect, it is dual channel.

For what your talking about in your day to day, 40GB would be plenty. I am basing this on the following article - https://larryjordan.com/articles/configure-a-mac-mini-2018-for-video-editing/ - and - https://larryjordan.com/articles/configure-an-imac-pro-for-video-editing/ - however, if you want more that’s certainly your prerogative. I don’t have as much to go on with Adobe Lightroom although a few photographer blogs can better speak to RAM needs.

More to your point, going to 64GB+ with a couple of 2x32GB Samsung DRAM DIMMs would let you move to 128GB in the future at the small expense of some memory bandwidth.

If you have the means to go to 128GB of DRAM, by all means, do so and then forget about it since you maxed it out. What I learned was that even if you do max out, it won’t necessarily make things any faster past 32GB or 64GB.

Hope this helps make things a little clearer.
 
Last edited:

gtg465x

macrumors 6502a
Sep 12, 2016
611
613
16 GB is sufficient for most people, 32 GB is power user territory, and anything more than 32 GB is overkill unless you are doing some very specific and extraordinary scientific compute, rendering, or virtualization tasks. I would say if you don’t know whether you need more than 32 GB, then you probably don’t.

As for the future, average RAM requirements double every 4 years, so if 16 GB is enough for most people today, then 64 GB should be enough for most people in 8 years. Power users may well be running 128 GB like it’s no big deal 8 years from now though, so it wouldn’t be that unreasonable to set yourself up to be able to upgrade to that if you plan to keep the computer a really long time.
 

Xanderman

macrumors newbie
Original poster
Nov 4, 2019
2
0
All great info. Thanks guys.

More to your point, going to 64GB+ with a couple of 2x32GB Samsung DRAM DIMMs would let you move to 128GB in the future at the small expense of some memory bandwidth.

Zdigital2015 - curious to hear what this cost is and why? Also, the Larry Jordan articles are great - thx.

16 GB is sufficient for most people, 32 GB is power user territory, and anything more than 32 GB is overkill unless you are doing some very specific and extraordinary scientific compute, rendering, or virtualization tasks. I would say if you don’t know whether you need more than 32 GB, then you probably don’t.

The machine is spec'd to run Lumion which is for architectural rendering. Basic requirements are 6GB VRAM/16GB RAM with the recommended being 11GB VRAM/64GB RAM for more complicated scenes. With 8GB VRAM and 32-64 GB RAM I'm at the lower end for the GPU but will prob be ok for my relatively simple scenes.
 
Last edited:

Zdigital2015

macrumors 68040
Jul 14, 2015
3,199
3,956
East Coast, United States
All great info. Thanks guys.



Zdigital2015 - curious to hear what this cost is and why? Also, the Larry Jordan articles are great - thx.



The machine is spec'd to run Lumion which is for architectural rendering. Basic requirements are 6GB VRAM/16GB RAM with the recommended being 11GB VRAM/64GB RAM for more complicated scenes. With 8GB VRAM and 32-64 GB RAM I'm at the lower end for the GPU but will prob be ok for my relatively simple scenes.

Samsung 32GB DDR4 2666MHz RAM Memory Module for Laptop Computers (260 Pin SODIMM, 1.2V) M471A4G43MB1 https://www.amazon.com/dp/B07N124XDS/ref=cm_sw_r_cp_api_i_B2AWDbTJ3D733

I have seen these modules quoted many times in these forums and the prices cannot be beat at this time. Hope this helps.
 
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