WillR Offline Upload & Sell: On
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So I tried some additional Lightroom benchmarking, and also some watching of what my Macbook was doing during the tests.
I'm using a 36 Gbyte M3 Pro Macbook. For each test, I started Lightroom from scratch, but I had a few other apps running as I would in normal operation (Mail, Calendar and Safari with about 5 tabs).
Test 1: I exported 1495 Sony A7riv raw files as full size JPEGS. This is similar to the test jhapeman did, although the raw files are about 20% larger than the Sony A1 files he used. The Macbook was not plugged in for this test, and it started "cold". That is, I had not done anything compute-intensive with it.
Time to export: 19 minutes 40 seconds. This is roughly comparable to the time jhapeman found for an M1 Max to export about the same number of Sony A1 files. So a pretty good performance.
About a minute into this test I noticed the fans come on. They stayed on for about a minute and then shut off. They did not come on again for the whole test. I was not monitoring cpu usage when this happened. Later, I looked at cpu usage and it was hovering around 1000% CPU and 90% GPU, whatever that actually means. I monitored memory pressure at various times during the test. Lightroom started at about 12 gbytes usage and slowly climbed to about 24 Gbytes over the ~ 20 minutes. For the first 80% of the test memory pressure was almost always green, with very occasional periods where it was yellow. In the last 20% of the test it was yellow more often. At the end of the test, the Macbook was warm, but not nearly as scorching as my old Intel machine would get.
Test 2: I decided to try the test again with the Macbook plugged in. In the end, I don't think it matters whether its plugged in or not, but I noticed something else. This time the fans did not come on at all. The test took a little longer: 20 minutes 40 seconds. Importantly, I had only waited about five minutes between the first test and the second.
My guess here was that the Macbook was doing some sort of throttling that occurred when the fans came on. Evidently, whatever it was doing to control thermals at the beginning of the first test was good enough, so that fans weren't needed for the rest of the time. In the second test, I was starting warm, and I'm guessing it throttled right from the start. So I think the machine is tuned to avoid fans as much as possible.
I tried a second set of tests
Test 3: I used about 1/3 the number of files in the export (470). The first time I did this test, the machine was still "warm", and, as in the second test, the fans never came on. Also there was not much memory pressure. This export took 7 minutes 40 seconds.
The time is a little longer than I expected given the number of files and the fact that there was no memory pressure, but it was roughly proportional to the number of files
Test 4: I did the same test, but started cold. And this time I watched CPU and GPU usage. At the start the CPU was ~1000% and the GPU was ~90%. As in the first test, about a minute in, the fans came on. At this point the CPU dropped to ~650% and the GPU to ~60%. After a minute, the fans stopped. But then slowly the CPU climbed back up to ~1000% and the GPU to ~90%. They stayed there, and the test took 7:36 seconds.
In this last test, you can see the throttling as the CPU and GPU utilization drop. But then what is happening after the fans shut off and the utilization climbs again? Is the Macbook throttling in a different way that doesn't show up in utilization? I have no idea.
Anyway, I'm happy than fans seem not to come on very much even in intensive operations.
-Will
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