AMD Ryzen 9 3900X Tested on Cheap B350 Motherboard 81

AMD Ryzen 9 3900X Tested on Cheap B350 Motherboard



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AMD trolled Intel's approach to PC enthusiasts on two fronts: all of its Ryzen processors feature an unlocked base-clock multiplier, and not just for select ones (Intel restricts this to its "K" SKUs), and, secondly, CPU overclocking isn't just accessible to its premium X370/X470/X570 chipsets, but also the mid-range B350 and B450 chipsets. You're out of luck if you just bought an Intel Core i9-9900K and decided to pair it with a B360 chipset motherboard. This extension of CPU overclocking to the mid-range chipset allows buyers to pair expensive processor models while cutting costs on the motherboard front. The B350 and B450 are very cheap chipsets and enable motherboards to be priced well under the $100 mark. Consider that in comparison to the latest AMD X570 motherboards that cost upward of $170.

AMD just launched its 3rd generation Ryzen "Zen 2" processors and has extended support for them to even the B350 and B450 chipsets. Quite a few B350 motherboards have received beta BIOS updates that enable 3rd generation Ryzen to run on them, including support for the mighty Ryzen 9 3900X 12-core processor that painted the wall with Core i9-9900K on Sunday. We wondered what would happen if we paired a cheap B350 chipset motherboard with this chip.

The ASUS Prime B350 Plus is as cheap as it gets. Priced at $70, this board provides the bare necessities and is targeted at gaming iCafes and light office usage scenarios. We updated it to the latest 5007 BIOS dated 1st July 2019 and dropped in our 12-core, 24-thread Ryzen 9 3900X processor. The board came to life without issues. We then decided to put it through our entire selection of tests from the CPU test suite. We did something similar with the AMD X470 chipset in a feature article posted on th 7th of July. In this review, we will be exploring performance, stability, and VRM temperatures of the Ryzen 3900X on B350.

Test Setup

Test System
Processor: AMD Ryzen 9 3900X (12-cores / 24 threads)
Zen 2, 3.8 GHz to 4.6 GHz
Motherboard:ASUS Prime B350-Plus
AMD B350, BIOS 5007
Cooling:Noctua NH-U14S
240 mm Asetek All-in-One
Memory:2x 8 GB G.SKILL Flare X DDR4
DDR4-3200 14-14-14-34
Graphics:EVGA GeForce RTX 2080 Ti FTW3 Ultra
Storage:1 TB SSD
Power Supply:Seasonic SS-860XP
Software:Windows 10 Professional 64-bit
Version 1903 (May 2019 Update)
Drivers:NVIDIA GeForce 430.63 WHQL
AMD Chipset

Performance Results

We ran our full suite of games and applications on the B350 platform with both the air cooler and water cooler installed.

While games showed no performance differences, application performance results had some surprising data points.

The chart above plots relative performance against the data from our Ryzen 9 3900X review in all applications. If performance is the same, the point gets put at "0%". If performance is better on B350, a positive value is used, and if performance is worse, that value goes into the negative.

While all results are within random variation, two results stick out immediately. These are for Blender and Corona—two heavily threaded rendering applications. It looks like when watercooling is used, they're losing a lot of performance. This is also true to a lesser degree for KeyShot and Photogrammetry, which are multi-threaded applications as well.

The explanation is that the air cooler has the benefit of creating some airflow around the CPU socket, which reduces VRM temperatures due to it picking up some of the heat on the VRMs. Enthusiasts often use watercooling to maximize their cooling performance for higher CPU overclocking, which is the root of the problem. With zero airflow around the socket area, VRM temperatures just keep climbing, which activates some safeguard that slows down the CPU to avoid physically damaging the motherboard, CPU, or other components.

We'll look at VRM temperatures in more detail on the next page.

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