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AMD Radeon RX 6400 Review

RDNA2 in a Tiny Low-Power Package

The Radeon RX 6400 is a brand new RDNA2 GPU that uses TSMC’s cutting-edge 6nm process. Sounds exciting, right? Well, maybe not so much once you get to see the results…

In a way, the RX 6400 is quite unique. This low-powered GPU doesn’t require external power, consumes less than 75 watts, and so it can received all of its power from the PCI Express slot. Moreover, AMD has branded this model with a total board power rating of just 53 watts, meaning it should use even less power than the GeForce GTX 1650.

This low power usage means it’s possible to create a low-profile version of the RX 6400 and this is what most card manufacturers have gone for. Our review sample comes in from PowerColor, and we can tell you, this RX 6400 is actually kind of cool, if it wasn’t for the excessive $160 MSRP.

Traditionally, sub-75W graphics cards like the RX 550 have been priced below $100 ($80 for the RX 550), but at twice the price of previous models, the RX 6400 is hard to get excited about. Of course, pricing of all graphics cards — and tech products for that matter — have increased from the RX 550 days, but the same was said when the Radeon 6500 XT launched a few months ago and that product is looking weaker than ever.

So the price sucks, we’re certainly not shocked, and at this point that probably won’t be news to anyone. For those of you looking for an affordable gaming graphics card, the RX 6400 won’t be it, or at least it shouldn’t be for anyone who has access to a decent second hand market, but we’ll discuss that in better detail towards the closing of this review.

Rather, let’s talk about who the RX 6400 might appeal to. As a low profile single-slot graphics card that doesn’t require external power, the RX 6400 can be thrown in anything with a PCIe x16 slot.

Popular targets for such a product are cheap Dell OptiPlex used desktops, people often snag models for well under $100 with respectable components such as 16 GB of RAM and a Core i5 processor. These PCs often only accept low-profile graphics cards and don’t provide PCIe power with the proprietary power unit. So having access to a relatively cheap low profile graphics card breathes new life into them as a budget gaming PC.

The RX 6400 already appears to be filling that niche a lot better, though paying $160 still seems excessive to get an old rust bucket up and gaming. At least to us, something along the lines of $80 seems a lot more appropriate.

Especially when you start to go over the specs…

There’s no delicate way to put this, the RX 6400 is a cut down version of the much loved RX 6500 XT, and yes, for those of you who can’t sense sarcasm, that was sarcasm…

The 6500 XT was almost universally hated, so it’ll be interesting to see if the power and size advantages of the 6400 can help it overcome a 25% reduction in core and ROP count, an 18% decrease in core frequency, and an 11% reduction in memory clocks and bandwidth.

The RX 6400 has inherited all the shortcomings that plagued the 6500 XT: we’re still looking at a PCIe 4.0 x4 interface, no hardware encoding, and no AV1 decode. Then to add insult to injury, AMD has locked out overclocking, so you can’t even squeeze out a little extra performance.

And with that, let’s get into the benchmark results. For testing we’re using our Ryzen 9 5950X GPU test system — and yes, we know no one is going to pair a budget graphics card with this CPU, but that’s not the point. We’re testing graphics performance and therefore wish to avoid introducing a CPU bottleneck which would skew the data.

For our low-end to entry-level testing we typically use medium quality settings, or settings that make sense for a given title. Please note the RX 6400 has been tested using both PCIe 4.0 and PCIe 3.0 on the same motherboard, we’ve simply toggled between the two in the BIOS. We’ve tested at 1080p and 1440p but we’ll focus on more relevant 1080p results.


Starting with Assassin’s Creed Valhalla, which has been tested at 1080p using the medium quality settings, we see that best case the RX 6400 is good for 54 fps on average which is far from impressive, only matching the old RX 570, though it was 8% faster than the GTX 1650, at least when using PCIe 4.0.

Switching to PCIe 3.0, which will be relevant for old OEM PCs, performance dropped by 9% and now the RX 6400 is slightly slower than the GTX 1650. We’re also looking at a 20% performance drop when compared to the 6500 XT.