I could use a sanity check on a cooling situation. It doesn't seem right or possible. Sorry for the long post.
CPU: AMD 9700X MB: Asus TUF Gaming B650E Wifi RAM: 4x16GB T-Force CL30 Case: Antec P182 (Giant quiet gaming case from 2007)
The system has been together for about 5 months. When I got the components, I picked up a $30 CAD generic cooler:
"iCan 6-Heatpipe CPU Cooler | 2*120mm PWM Fans with Rainbow Color | TDP - 265W | Fan Speed upto 1800RPM | Fan Noise - 31DBA"
It all ran OK, was quiet but not silent. Only has fan noise when working hard. In other words: Great.
I'm doing a bunch of ffmpeg/x265 transcode benchmarking. With the iCan cooler, it would thermal throttle (75C throttle, 76C measured) at 5350MHz. It would bounce between about 5200 and 5450.
Anyway, a buddy told me the Noctua D15 is the best air cooler going. I did some reading. He seems to be right. It is a highly regarded cooler.
The D15 fits into the system fine but only one of the 140MM fans will fit. The 140mm fan won't fit in the back, due to the VRMs. The 140mm fan won't fit in the front, due to RAM. So, the D15 has a 140mm stock fan and a 120mm screamer (140CFM). That's a lot of air.
It doesn't cool nearly as well. Not even close. I've bumped up the thermal throttle to 80C (where it sits 100% of the time while transcoding). Fans are set to 100%, all the time. It barely makes 5GHz with the D15. Average is about 4900MHz.
I put the iCan cooler back on and it went back to almost boost clock frequency.
The thermal paste is very well done. I was super careful between cooler changes and I clean the old stuff with alcohol before applying fresh and mounting another cooler.
Why does the smaller cooler with a far worse machined CPU contact area cool better than the gigantic D15?
I will say, when using QFan and the iCan cooler, the fans ramp in about 2 seconds after launching ffmpeg. QFan with the D15, it takes about 4~5 seconds for the fans to fully ramp. The D15 has a substantially heavier CPU block and this does seem to add considerable inertia (which is nice).
Any thoughts?
Minor update:
I pulled the D15 and discovered it was not interfacing with the CPU in the center in the block. The mounting brackets have two sets of holes so I shifted it to put the heat closer to the center of the cooling block.
It didn't make much difference. I won't know until I've run my entire test suite. I hate to jump to any conclusions after 15m of testing. So far, it's hitting 5.14 GHz, where it was not quite hitting 5GHz before.
I'll let it run some benchmarks overnight and then analyze the speeds and temps.
Thank you for the ideas and advice. I really appreciate it.