APE2027 slow export when using "Render at Maximum Depth"

Thanks for looking into this issue. I’ve recorded a video that shows exactly how it behaves:

Input video is from a GoPro camera: 4K 60fps, 5 min 20 sec duration

• Export with no effects/changes: ~3 min

• Export with HSL Tuner added (Render at Max Depth OFF): ~9 min

• Export with HSL Tuner added (Render at Max Depth ON): ~34 min

As you can clearly see, adding the HSL Tuner effect along with Render at Max Depth increased the export time from 3 minutes to over 30 minutes. That is a massive difference, and this is precisely the issue I am describing here.

It is also very evident that CPU utilization doesn't increase when Render at Max Depth is turned on—in fact, it drops. This indicates that the bottleneck lies elsewhere, as the whole process slows down significantly.

It’s not in the video, but when I export a clip with Render at Max Depth enabled without the HSL Tuner effect, the export time doesn't increase at all. So the source of the problem is definitely the HSL Tuner. It's possible that other CPU-bound effects cause similar issues, but I haven't tested those yet.

My system specs:

• Intel i9 9900K

• NVIDIA RTX 5060 Ti

• 32GB RAM

Thanks for the suggestion, but the built-in Color Correction & Grading tool (Lumetri) operates much more globally. It simply isn't as precise or effective as the HSL Tuner when it comes to isolating and tweaking specific color channels.

A prime example is footage from GoPro cameras. They often introduce a specific, warm, yellowish-orange color cast on skin tones. With a global color tool, adjusting the temperature or saturation to fix the face usually ends up ruining the rest of the scene (like making the background look dull or overly cold).

With the HSL Tuner, I can specifically target just the orange/yellow hue and drop its saturation or tweak its lightness, making skin tones look completely natural again without affecting the vibrant blue of the sky or the surrounding environment. That targeted control is exactly why HSL is essential here.

Thank you for your reply, but I think you may have misunderstood the core of my issue, even though I tried to explain it clearly.

I completely understand the basic logic that processing more data takes more time. That is obvious. My concern is not about the fact that it takes longer, but about the scale of the performance drop and how the system resources are being utilized.

An export time jumping from 30 minutes to 2 hours or more just by enabling Render at Maximum Depth is a drastic increase that is hard to justify, especially given the hardware behavior:

1. Hardware Bottleneck / Low Utilization: As I mentioned in my original post, neither my CPU nor my GPU is being heavily utilized during this process. Instead of seeing all cores/threads maxed out to handle the heavy workload, I see very low overall utilization. If the system is not actually working hard, it suggests a bottleneck elsewhere in the rendering pipeline rather than a simple lack of compute power.

2. Optimization & GPU Acceleration: If combining HSL with Render at Maximum Depth causes such a severe slowdown without maxing out system resources, it points to either a software optimization issue, memory bandwidth limitations, or a CPU-bound thread lock. If this effect is not GPU-accelerated, it clearly demonstrates why it needs to be, or at least why the CPU multithreading efficiency needs attention here.

Leaving this behavior as-is effectively renders the combination of HSL and Maximum Depth unusable in real-world workflows, which is a shame.

If you want to do proper color correction might want to look for more professional editing software.