A lot of tuning later...
Here are a few temps I'm getting on my I7-8700 after I've tuned it to allow for 4.3GHZ speed on all cores while encoding. Right now that includes XMP with 3200mhz DDR4, Noctua NH-L12 with only the 92mm fan, bottom Noctua 92mm intake fan with LNA, CPU set for 95 Watts long term power, and a -.12 on the VCORE. Ambient temp was 72F. The system has nothing around it to impede airflow.
With this setup, AIDA64 did not crash or throttle on stability tests.
Converting a 1.5GB 48 FPS Go Pro file to HEVC at maximum quality in Adobe with CUDA turned on. This is a 2.5 hour long rendering test that uses all 6 cores and 12 threads. The CPU max turbo bounces between 4.0 and 4.3 GHZ, with 4.2 being most common. The highest temp observed was 99C for a few seconds on two of the cores. All others were either 95 or 96C. The average temp was about 88C.
Obviously this is borderline throttling. So my next step is to upgrade the stock 92mm fan of the NH-L12 from the 1600RPM model to the 2000RPM model.
For reference: Leaving the CPU at stock settings, with XMP DDR4-3200 enabled, and multi-core enhancement off, the same rendering turbos between 3.4 and 3.6 GHZ, at an average temp of 75C on the cores.
My next test will be stock settings as listed in the above paragraph, but with the max long term TDP at 75 watts instead of the stock 65.
After that, I will rerun the tests with the top off to see if there is a notable difference.
Keep in mind for anyone looking at this case, for gaming and day to day things, it runs fine at 4.3 GHZ stock all day long. I'm really trying to push the edge of ITX tech by doing an Encoding and video editing machine in such a small case on compact air cooling alone, while keeping it silent at idle, and very very quiet under load without delidding. It's a fun challenge.
That said, I might delid the thing soon.
