1. Introduction - Taming the 64-core Beast2. Test Samples - IceGiant, Noctua, be quiet!, Corsair3. Testing on the 3990X - Our Approach4. Test Procedures5. PBO-1000 Testing - CPU Temperatures and Power6. PBO-1000 Testing - VRM Temperatures7. PBO-1000 Testing - Clock Speeds and Cooling Dynamics8. Manual OC Testing - CPU Temperatures9. Manual OC Testing - CPU Power and VRM Temperatures10. Noise Testing11. What's Going On With be quiet! and Cooler Master?12. Closing Thoughts - Cooling Threadripper 3990X is Tough!13. View All Pages

PBO-1000 Testing:

Our Precision Boost Overdrive test highlights each cooler operating with the CPU pushed using PBO set to 1000W PPT, 1000A EDC, 1000A TDC, and +200MHz attempted frequency offset. AIDA64 Stress Test applies the load.

Ambient temperature is 23°C and varies by no more than +/-1°C. Figures reported are read temperatures, not deltas.

Starting out with PBO temperatures we see, unsurprisingly, each cooler running the 3990X at its 95C temperature limit. The only real point of importance here is that none of the coolers are sufficiently overpowered to run the CPU below its 95C limit when mounted inside our Fractal chassis.

This power chart is more important than straight temperatures when looking at PBO results. The indication of higher power draw is a positive from a CPU cooler’s perspective as it highlights how a unit can handle more thermal load from the CPU than its competitor which should, in theory, translate into greater overclocking capability.

We see the IceGiant ProSiphon Elite topping the chart with a reported CPU package power allowance of just under 500W. That is a remarkable result from a cooler that is fundamentally air, not closed loop or open loop liquid, in design even if fan speeds are high.

Also of note is the superb showing displayed by Noctua’s single-tower NH-U14S TR4-SP3 in both single- and dual-fan mode. The modestly sized 140mm-class air cooler manages up to 450W of Threadripper 3990X cooling capacity and does so with low fan speeds that translate into preferential noise levels. The speed reduced IceGiant cooler manages a similar load level when choked down to 1500 RPM fan speed.

Albeit with fast-running fans, Corsair’s 280mm AIO puts in a reasonable showing given that its cold plate is not Threadripper optimised and does not cover the full heatspreader. 400W of 3990X cooling capacity is a strong result when viewed in isolation, and the relative benefits of AIO versus air (depending on your use case, of course) may highlight this result as a positive to some potential buyers.

be quiet! rates the unit for 250W TDP on the box (whatever that means and however it is tested) so the cooler’s result of 365W 3990X CPU package power is certainly strong but it is a little surprising compared to Noctua’s performance. More on this point later.

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