See, when it comes to the X3D chips, there are factors to consider:
It depends on the generation. 9000 series x3d tends to run cooler vs 7000 series x3d. Why? Because of the v-cache placement, which AMD overhauled with 9000. As a result, the v-cache on the 7000 series runs way hotter.
The 9000x3d parts can still be (somewhat) overclocked, not so with the 7000x3d chips (to protect the v-cache, due to its placement). Thus, they are designed to hit the designated thermal limit (depending on what you set in the BIOS. Mine is set to 89c). The cooler you keep it, the more chances you have of sustaining a longer boost clock
Under a Cinebench '24 run, my 7800x3d under a D15 (with two fans) would hit 89c easily in winter, and the sustained boost would drop.
When I switched to the LFIII 360, it now maxes out at 83- 84 °C in the summer heat. Boost clocks do not drop.
In both scenarios, my case is a Lancool 216.
Even in games, with my LFIII, I noticed fewer variations in CPU clocks vs with my D15. This is my documented experience.
Whats the difference in performance ?
For me setting a temp limit of 79C with AG620 degrades performance by less than a percent in cinebench multicore.
Overall uv/oc + 79C templimit was about a percent up from base performance which i am happy with.
AG620 won’t run a 9800X3D at 85C, it will be lower even at load, maybe late 70s. That 85C is for my puny AK400 & 85C is not an unsafe temp as AMD runs its normal X CPUs at 95C by default.
Ran a test, current ambient temp is like 24C in Bengaluru. Last I tested was in summer with ambient over 30C. CPU cooler is set to run at max RPM post 70C. Other fans also hit max RPM around 75C.
Fan setup in Lancool II Mesh: 3x intake at front (stock fans), 1x intake at bottom below GPU & 1x exhaust at back (both Arctic P12). -20 offset for undervolting.
I am not sure if Gigabyte removes the temp limit, but 9800X3D was running above 90C at stock when I tested initially. Now under 75C is surprising to me, but all core freq is maintained at 5.2GHz.
Same here ran cinebench24 just now, set temp limit to manual in asrock bios at 90C. Max temp reached was 84C, then set CPU boost clock override to +200 and the temps reached 90 now. All this is on a -30 offset, this shows the AK400 is more than able to handle the cpu if not using CPU boost clock override. Ambient temp here is around 32C.
I guess this just means the AMD IHS is really poorly designed and it doesnt really matter what coolers you pick for them.. AG620 makes sense even for the ultra premium builds.
