Can we talk about how long blend modes actually take to render?

I was timing my exports in Sketch last Tuesday, just for fun, and found out that a simple multiply layer over a photo adds nearly 3 seconds to every PNG save. I was floored because I've been stacking blend modes for years thinking the delay was just my old Mac. Turns out the docs on Sketch's site show rendering is CPU-heavy, not GPU, which explains why my fan sounds like a jet engine. Has anyone else benchmarked their export times and found a hidden culprit like this?

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iris_park3d ago

My export from last month with 6 blend modes and a big group mask took 47 seconds on a 2019 iMac, so your 3 seconds sounds like a dream to me. I did the same timing test after reading your post and yeah, my CPU spiked to 90 percent while the GPU sat there bored. It feels like the software is doing math on a calculator instead of using the machine's actual power. Honestly, I've started flattening layers before export just to keep my sanity and my fan speed down.