Overclocking and Temperatures
While overclocking, the ambient temperature was kept at a constant 20°c (68°f). Our engineering sample 9900k was the same chip used on both the Z390 Aorus Pro and the Z390 Aorus Xtreme. A quick side note. Not all “confidential” processors are binned as so many believe. In fact, our 9900k doesn’t do the best with overclocking. In fact, it hates taking the extra voltage. On the Z390 Aorus Pro, the best we could manage was 5.0 GHz at 1.344 volts. With the same 9900k installed on the Z390 Aorus Xtreme Waterforce, we managed to get the chip to 5.2 GHz at 1.308 volts. When we tried to pump more voltage to the processor, the system crashed.
Gigabyte has released an official overclocking guide for the 9900k and recommends setting T junction to 110°c. This will help to prevent some crashes due to thermal limits while overclocking. There are several other steps Gigabyte recommend you take as well and we highly recommend following their overclocking guide if you want to get the most out of you I9 9900k whiles it’s on an Aorus Z390 motherboard. To check out that guide, click here; https://www.gigabyte.com/FileUpload/Global/multimedia/2/file/525/946.pdf.
To validate our overclock, we use the AIDA64 Stability Test. This test puts a 100% load on your CPU and isn’t exactly representative of an everyday work load. First, the results from the Z390 Aorus Pro. On the Aorus Pro, the 9900k was cooled by a modified Swiftech H320 X2. By modified, it has an EK Supremacy EVO waterblock and EK coolant running in the cooler. At its stock speeds on the Aorus Pro, the I9 9900k idled between 30°c When we overclocked the processor to 5.0, the idled temperature went up to around 35°c on average. When we ran the CPU test, it did fine and hit only 72°c after a 15-minute test. However, when I ran the FPU test at anything over 4.8 GHz, it hit thermal limits and began to throttle after about 5 minutes. Even running at stock speeds on the Aorus Pro, our 9900k would hit well into the 90s after a few minutes and began to throttle.
On the Z390 Aorus Xtreme Waterforce, the results were much different. The system was cooled buy an XSPC D5 Photon 270 Reservoir and pump combo and a 360 x 60 mm EK radiator running in a push-pull configuration with EK Vadar Fans. So, plenty of cooling. Right away, the idle temperature at the processors stock speed was at 25°c. This temperature was recorded about 20 minutes from a cold boot. Even when overclocked, the idle temperature never went above 29°c. When running the AIDA64 Stability Test, the 9900k with the full cover monoblock hit only 66°c after about 15 minutes running the CPU stability test. During the FPU test, the processor did not throttle. Even though it did get into the lower 90s, the I9 9900k stayed at 5.0 GHz during the FPU stability testing and at 5.2 during the CPU stability testing. The difference in the results of the two motherboards goes to show not only how good cooling will boost your performance, but also how well the Z390 Aorus Xtreme Waterforce can cool even the I9 9900k, a chip known to run hot.
A quick side note regarding the M.2 Thermal Guards. For this review, only the top M.2 slot was occupied. However, the same Crucial P1 M.2 was tested on both the Z390 Aorus Pro with no thermal guard and on the Z390 Aorus Xtreme Waterforce. There was about a 6°c difference in temperature between the Z390 Aorus Pro with no thermal guard and the Z390 Aorus Xtreme Waterforce.