As we anticipated when we reviewed AMD's new flagship 16-core Ryzen 9 3950X, rather than testing it on the very high-end Gigabyte X570 Aorus Xtreme, we want to see how it does on the low-end. We're not bothering with A320 boards – that's a bit too silly we figured – but decent AMD B450 boards do make sense, maybe not right now, but in the future as a potential upgrade for many AM4 owners. Here's what we're thinking...

The R9 3950X is a $750 processor, so pairing it with motherboards priced a little over $100 wouldn't be considered by most right now. However, in the not too distant future you'll be able to snag a second hand 3950X at a significant discount, that's just the way it seems to go with AMD processors.

There are a few reasons for this, but the two main ones are that AMD doesn't lock you into a platform like Intel, so second hand shoppers have significantly more options. And also AMD seems to have the habit of reducing prices of CPUs over time, and this obviously creates a knock-on effect for second hand sales.

For example, the 3-year-old Core i7-7700K released at $340, still costs ~$220 to this day on the second hand market. That's a mere 35% discount for a part with no warranty. Meanwhile, the Ryzen 7 1700X which was priced at $400 almost 3 years ago can be easily had for $100, a 75% discount from new.

What's more shocking is that in late 2019, for almost all tasks the 1700X is a significantly better processor. Moreover, within another year or two there'll be almost no new game or application where the quad-core Core i7 can hold a candle to the 8-core Ryzen 7.

As another example, the more recently released Ryzen 7 2700X launched at $330. Today though you can snap one up for as little as $150 on eBay. In another year there's no way you'll be paying over $100. So while the Ryzen 9 3950X might cost $750 today, you can bet within a year it will be less costly and within 2-3 years it will be a hot item for second hand shoppers on the AM4 platform, the same also applies to the 3900X.

When you bought that 2nd-gen Ryzen CPU a year ago, if you did so with a decent B450 motherboard, you're golden. In 2-3 years' time you should be looking at a 16-core upgrade for around what a new Ryzen 5 2600 would have set you back in 2018.

Mark this part of the sentence with an asterisk though, *decent B450 board*, there weren't many of them and we discovered that back in mid 2018 when we published our B450 VRM temp test. Asus and Gigabyte produced some of the worst budget boards we'd seen in some time, while MSI surprised us with high-quality options in the B450 Tomahawk and B450 Pro Carbon.

For a quick recap, the Asrock B450 Gaming K4 peaked at 86 degrees and the MSI B450 Tomahawk at 88 degrees using a stock Ryzen 7 2700X in a 21 C room with no direct air-flow. Meanwhile the Asus ROG Strix B450-F Gaming reached 109 degrees and the Gigabyte B450 Aorus Pro Wi-Fi, an incredible 121 degrees. The testing also included a high air-flow ATX case test and here the Asus and Gigabyte boards ran much cooler at between 64 and 67 degrees.

But for us, the 'no direct air-flow' testing was the most telling. At the time we knew the AM4 platform was going to be around for a few more years and we knew more extreme processors, just like the 3900X and 3950X would be released. Given what we already know about these B450 motherboards based on tests conducted with the Ryzen 7 2700X, we don't expect too many surprises once we put the higher-end Ryzen 9 3950X on the driver's seat.

This time though we won't be testing without direct air-flow. That would be asking too much of these sub-$150 boards, but since we're testing with an optimal ambient room temperature, 21 degrees, we will include a low air-flow configuration along with a high-air flow configuration. All testing takes place inside the Corsair Crystal 570X.

Ryzen 9 / B450 VRM Temperature Test

The low air-flow configuration sees a pair of in-take fans mounted in the front of the case on a 240mm AIO. Then we have a single 120mm exhaust fan in the rear of the case, a pretty standard configuration.

The high air-flow configuration adds a pair of in-take fans at the top of the case, normally you'd configure these as exhaust fans, but for the purpose of this test we wanted to blow cool air over the board's VRM heatsinks for maximum cooling performance, so we consider this a best-case scenario.

All motherboards were using the latest BIOS and all are running AGESA version The Ryzen 9 3950X has been left stock, so it should be slightly less demanding than the 3900X. Let's now get into the results...

First lets run a few benchmarks to see how each board performs with the Ryzen 9 3950X using the low air-flow configuration. Please note the Asus ROG Strix B450-F Gaming overvolted the 3950X resulting in a slight performance boost, but of course this also increased VRM temps, so we set a negative 0.150v offset which put the Asus board more inline with the voltages seen from the Gigabyte and MSI boards.

Unfortunately this reduced performance and here we see the Cinebench R20 multi-core score drop by 6% when compared to the Tomahawk and Aorus Pro. The MSI and Gigabyte boards managed to match the performance seen on the $700 Aorus Xtreme, so that was nice to see.

We see pretty similar performance trends when looking at single core performance, although we're only utilizing a single core, the under-volt still reduced performance with the B450-F Gaming.

Contrary to what we just saw with Cinebench, the Asus board actually performed slightly better with the under-volt in this long run Blender test and the reason for that is lower VRM temps. Basically the lower voltage helped reduce CPU throttling and we'll look at this more in a moment. Performance-wise we do see that the Tomahawk and Aorus Pro were able to match the Aorus Xtreme, so that's another good sign for these budget boards.

Here you can see just how poorly the Asus Strix B450-F Gaming is configured using the latest BIOS. The board pushed total system consumption with the 3950X to 266 watts, that's almost 20% more power than the Tomahawk using the same CPU.

In fact, the MSI Tomahawk and Gigabyte Aorus Pro saw reduced power consumption by almost 10% when compared to the high-end X570 Aorus Xtreme motherboard.

Here's a look at the VRM temperature results for the low air-flow configuration, above we're showing the operating temperature and the resulting performance side-by-side, lower is better for both.

The MSI Tomahawk produced a strong result in Blender, taking 1819 seconds to complete the test and that places it on par with the best X570 boards. The VRM also peaked at just 87 degrees, which is an exceptional result for a board that costs ~$120.

The Gigabyte B450 Aorus Pro WiFi surprised with the second best result, though it ran 10 degrees hotter than the Tomahawk, and while that makes it a bit toasty, that is a safe operating temperature and the board avoided throttling the 3950X.

The Asus Strix B450-F Gaming was a disaster out of the box, hitting 112 C which resulted in the 3950X downclocking. This saw the completion time increase by 7% when compared to the Tomahawk. Performance aside though, we consider this a fail as running at well over 100 C will shorten the lifespan of the board. Even with the under-volt the board still under performed and ran excessively hot, so basically the B450-F Gaming is a terrible pairing for the 3900X or 3950X and frankly it's really no good with the Ryzen 7 2700X either.

There is some good news though, if you direct a large volume of cool air over the Asus board, it's usable, not great relative to the competiton but it works a little better. Performance is still down on the Tomahawk, so even at 88 C we were running into some throttling in this 30 minute test.

The MSI Tomahawk was impressive, peaking at just 66 C degrees and while this might be an optimal setup, you can expect this board to operate somewhere between 66 and 87 degrees depending on setup and ambient temperature.

The Gigabyte Aorus Pro ran 15 degrees hotter which isn't great, but the board avoided any throttling and did manage to get the most out of the 3950X, so a pass overall.

Closing Thoughts

The MSI B450 Tomahawk once again proves why it's the best value, best all-round B450 motherboard. Although we used the newer Max version for this test, performance is identical to the original, you're just getting better BIOS support with the newer version, which sadly still doesn't appear to be on sale in the US.

For those looking at buying a B450 board today for use with something like the Ryzen 5 3600 or Ryzen 7 3700X, we still strongly suggest purchasing either the MSI B450 Tomahawk or Pro Carbon. The Pro Carbon is a little pricey at around $140, for that money you could just as well look at an X570 board. We strongly advise you to skip the entry-level MSI X570 boards as they are horrible, in the same class as the Asus B450-F Gaming.

Conversely, we'd actually recommend Asus' X570 range. The TUF Gaming X570-Plus, for example, is a cracking good board for $165. For more detailed information on great motherboard picks check out our Top 5 X570 motherboards and favorite B450 motherboards for a good summary.

Those of you who took our advice and bought the MSI B450 Tomahawk for your build, good news, you're set. Once those 3900X and 3950X CPUs start to tumble in price you'll be primed and ready for a serious CPU upgrade without having to change a thing.

One last note, we'll say the Gigabyte B450 Aorus Pro WiFi surprised us in this test. Last time we ran a similar test with the initial F1 BIOS release using a Ryzen 7 2700X it was a disaster. But Gigabyte seems to have done a good job tuning up the board, and while it's still far from impressive, it's now usable even with the 3950X, so that's great to see.

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