Cinebench - No Power Limits Results
With Raptor Lake’s i9-13900K pushing all-core turbo speeds of 5.5ghz, even the strongest of coolers hit TJ Max while running Cinebench R23 and other demanding scenarios. As no cooler that we’ve tested thus far can pass R23 testing using a traditional delta over ambient measurement, we’ll be comparing the overall benchmark score and the CPUs clock speeds instead.
The results below are for a 10-minute testing run, but to be sure that was sufficiently long we also retested both Thermalright’s Assassin X 120 R SE and DeepCool’s LT720 with a 30-minute Cinebench test. The results didn’t change much at all with the longer test: The average clock speeds maintained dropped by 29MHz on DeepCool’s LT720 and 31MHz on Thermalright’s Assassin X 120 R SE. Looking at this another way, that’s an incredibly small 0.6% difference in clock speeds maintained, a margin of error difference that tells us that the 10 minute tests are indeed long enough to properly test the coolers.
Starting with the Thermalright SFF cooler, clocks of 4722MHz were maintained consuming 198W on average. The $20 Assassin 120 R SE sustained 5055MHz (an increase of 333MHz) with the CPU consuming an average of 245W. This shows some of the improvements Raptor Lake brings over Alder Lake, as the i9-12900K only maintained up to 4900MHz while consuming the same amount of power - and required a hefty liquid cooler to maintain that speed in Cinebench. The score achieved here was 37,555 points, approximately 10,000 points higher than our i9-12900K scored with top-tier cooling.
With the next level of air cooling, clock speeds maintained with DeepCool’s AG620 increased by 188 MHz in comparison to the Assassin 120 R SE, resulting in the benchmark score rising by 1294 points. Average power consumption increased to 277 watts as a result of the higher clock speeds.
Finally, when testing with DeepCool’s LT720 liquid cooler, clock speeds increased by another 219MHz. At 5462, this is just 38MHz shy of the maximum clock speed held during multicore workloads. This in turn led to a benchmark score result that’s 1059 points better than the AG620 air cooler. And those high clock speeds don’t come easy in terms of efficiency; power consumption here averaged 315W.
Also note that, while attempting to cool the CPU without power limits, the coolers will be noisy! Because they are unable to keep the CPU below TJ max, the fans will run at 100% in this scenario.
Looking at this another way, you lose 12% of potential performance in the most demanding workloads when pairing the i9-13900K with an SFF cooler. That deficit drops to 5.9% with a single tower air cooler, and drops again to 2.7% with a high-end air cooler.
Cinebench 200W Results
While the previous results showing performance with power limits is interesting, I would advise against running the 13900K without power limits. Because attempting to cool a CPU that’s using over 300W results in a lot of fan noise and heat output for very little increased performance. Most workloads won’t use 300W+ anyway, but in those that do, performance is only reduced by about 10% when limiting power consumption to 200W.
Restricting power consumption to a reasonable 200W results in a massive decrease in cooling difficulty. Both mainstream air coolers performed decently here, at only 54 and 58 degrees Celcius over ambient temperature. The SFF cooler struggled here, reaching TJMax and thermal throttling slightly - only cooling an average of 193W.
While DeepCool’s LT720 averaged 75 degrees C over ambient with power limits removed, at 200W the thermal measurement dropped to 47 degrees C, a 28-degree improvement in temperature! The main benefit of stronger coolers in this scenario is lower noise levels. For example, the LT720 ran 0.3 dBA quieter than the AG620 did in 200W testing.
Cinebench 125W Results
The lowest power limit I tested at is 125W. I recommend those who prioritize PCs silence to set CPU power consumption to these levels. Because at 125W, any half-decent CPU cooler tends to run very quietly.
This is also the lowest level where I can measure reliable noise measurements. Lower power consumption causes the noise of the CPU cooler to fall below the noise created by the system fans (even while restricted to 35% speed). Both of the mainstream air coolers measured at 0.9 dBA over ambient in this test, with the liquid cooler slightly louder, at 1.4 dBA over ambient. While it was still very quiet in this scenario, the SFF cooler was the loudest in this test at 2.1 dBA over ambient.
The level of cooling you’ll need for Intel’s Core i9-13900K will depend on the performance you expect out of it, as well as whatever power limit you set for the CPU. For common, bursty tasks, even an entry-level aftermarket cooler will allow the CPU to run at its highest supported stock clock speeds. For more demanding tasks, something that makes use of all or most of the cores, a strong liquid cooler will improve performance by up to 12%, while also potentially allowing for overclocking headroom.