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joshn87027797
joshn87027797
Known Participant
August 14, 2025
Answered

LrC Not using full CPU and RAM

  • August 14, 2025
  • 1 reply
  • 151 views

Bit of an odd one as I think most questions are around LrC using too much CPU and RAM 🙂

I was doing an import today which does the following:

  • Imports 671 photos
  • Apply Preset
  • Convert to DNG
  • Build Smart Previews

This was from a CfExpress Card to a Samsung 980 NVME SSD

I believe it copies the data first, and then does the preset/convert/previews after as that's what task manager seems to indicate.

i.e. a lot of disk activity on the card + SSD, then not much but a lot more CPU.

However, the CPU goes through this weird cycle of 100% CPU for a bit, and then nothing.

The RAM usage does also not really increase that much considering I've just imported about 16 GB worth of data.

I've posted a picture at the bottom of this post, but wondering if this is normal for LrC, or if something else may be a bottleneck for this?

 

Correct answer Anshul_Saini

Hi @joshn87027797,

 

Thank you for sharing the details and screenshot. Based on your description, what you are seeing is expected behavior in Lightroom Classic. Lightroom Classic does not always fully utilize CPU and RAM. It works in sequential stages: copying files, then converting to DNG, applying presets, and finally building previews. Each stage stresses different system resources (disk first, then CPU).
The import process is also limited by disk speed and card reader throughput. Even with a fast NVMe SSD and CFExpress card, the bottleneck may shift between I/O and CPU, so you will not see sustained maximum usage of both CPU and RAM together. Also, a good CFExpress Type B card usually has half the speed of a high-end NVMe SSD like the Samsung 980. In practice, the bottleneck is often the card reader.


If you would like to review optimization steps for performance, see: https://adobe.ly/41de7HL


In summary, this cycling behavior of CPU and low RAM usage is normal and does not indicate a fault with your hardware or Lightroom Classic.

 

Best,

Anshul Saini

1 reply

Anshul_Saini
Community Manager
Anshul_SainiCommunity ManagerCorrect answer
Community Manager
August 20, 2025

Hi @joshn87027797,

 

Thank you for sharing the details and screenshot. Based on your description, what you are seeing is expected behavior in Lightroom Classic. Lightroom Classic does not always fully utilize CPU and RAM. It works in sequential stages: copying files, then converting to DNG, applying presets, and finally building previews. Each stage stresses different system resources (disk first, then CPU).
The import process is also limited by disk speed and card reader throughput. Even with a fast NVMe SSD and CFExpress card, the bottleneck may shift between I/O and CPU, so you will not see sustained maximum usage of both CPU and RAM together. Also, a good CFExpress Type B card usually has half the speed of a high-end NVMe SSD like the Samsung 980. In practice, the bottleneck is often the card reader.


If you would like to review optimization steps for performance, see: https://adobe.ly/41de7HL


In summary, this cycling behavior of CPU and low RAM usage is normal and does not indicate a fault with your hardware or Lightroom Classic.

 

Best,

Anshul Saini

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