Question regarding GT 720 compatibility with recent versions of 3DF Zephyr Lite

[Jonathan C]

Love your software, I'm getting amazing results using nothing but an iPhone 6s but it's taking a looong time to process 50 images with no graphics card in my old Dell Optiplex with an i5 2500 3.3 GHz, 8 GB with a 240 GB SSD. One of my friends gave me a Lenovo GT 720 card with 1 GB of DDR 5 memory (CUDA rating of 3.5) and it works fine in the computer and nicely accelerates version 3.142 of 3DF Zephyr which I installed after the most recent version crashed fairly late in the processing stream with the card installed even with only nine 12 MP images from my iPhone. The benchmark crashes too with the card installed but oddly enough the camera calibration utility does complete processing with the card.

Evidently the card is Kepler 2.0 technology as I found out after considerable searching and the latest CUDA requires a Kepler 3.0 or greater card, or at least that is my understanding so far. Is there any way to get this GT 720 card to work in my antiquated machine with your latest version?

I'm sorry to bother you over such low end hardware but I'm a pensioner trying to do photogrammetry as part of my hobby and cost is a major issue.

Thanks for providing such outstanding software to the community, a very impressive effort.. I'm including a couple of screenshots from my system on which I have done zero manual cleanup at all, even the vegetation looks crisp.

Warmest Regards,
Jonathan

[cam3d]

Hi Jonathan C

One of the things which stands out the most re: your pc is the very low RAM count (8gb) which, depending on the background usage of your resources, could be the cause of the massive slowdown.

The GT 720 has CUDA above 3.0 which should be fine as it's within spec for the current software build. Are you able to share a log with us to help determine the root cause of the issue?

https://www.3dflow.net/technology/documents/3df-zephyr-tutorials/how-to-locate-3df-zephyr-log-files/

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If you could let us know your processing settings too that would be very helpful!

[Jonathan C]

Hi Jonathan C

One of the things which stands out the most re: your pc is the very low RAM count (8gb) which, depending on the background usage of your resources, could be the cause of the massive slowdown.

The GT 720 has CUDA above 3.0 which should be fine as it's within spec for the current software build. Are you able to share a log with us to help determine the root cause of the issue?

https://www.3dflow.net/technology/documents/3df-zephyr-tutorials/how-to-locate-3df-zephyr-log-files/

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If you could let us know your processing settings too that would be very helpful!

Thanks for the reply,

I've attached a log file from a run with a freshly booted computer, default settings other than multi texture.

[cam3d]

Jonathan C Thanks! Andreawhen you get a chance could you have a look into this? ty

[Andrea Alessi]

Hi Jonathan,

from the log you can actually see it is running correctly in GPU. It's not a great card as it is fairly old now, but it can run zephyr indeed.

I'm not sure why it crashes rather than failing gracefully and we will investigate the issue, thank you for reporting! I strongly suggest increasing your ram memory (as you have the bare minimum unfortunately to run zephyr). I also suggest you use JPGs rather than TIFF files (unless you need 32 bit textures) which will lower the memory footprint and the results will pretty much be the same.

[Jonathan C]

This was just the best performing GPU on paper of a batch I had access to, sadly most of the rest are not CUDA friendly at all

I'm in the habit of using TIFF due to a background in astrophotography where it can make a substantial difference, changing to JPG won't be an issue for me. Unfortunately 8 GB is all the memory my motherboard will handle, I'm looking into upgrading but that may take some time to implement since it will require a new case and other accessories.

If I do a run, let it crash, turn off the graphics card processing and continue will I gain the speed advantage of GPU processing up to that point?

[Roberto]

From advanced texture settings, I also suggest changing the texture size to 4096 to reduce the memory footprint in case of low RAM. You can leave the number of textures to 4 or increase it to 8 or 16 (16 * 4k * 4k is equal to 4 * 8k * 8k, but the first will use a lower amount of maximum memory).