Radeon RX 6400 review (Page 25)

Radeon RX 6400 review

Graphics cards 1048 Page 25 of 25 Published 2022-09-08 13:31 by Hilbert Hagedoorn

Final words and conclusion

Final words

We believe the RX 6400 would have been an acceptable buy a year ago with major GPU shortages, but that dynamic has shifted. As long as you avoid newer games and features like Raytracing, you can reach framerates in the 50 FPS range with titles that do not exhaust the 4 GB graphics RAM at 160 USD. Even at the lowest feasible level, the card is Raytracing compatible but lacks performance. For low-level esport gaming at 160 USD, as far as I am concerned, this release is a bit of a cluster-frack. The memory bandwidth is extremely constrained at 64-bit, although the 16MB L3 cache compensates greatly until it runs out. The biggest limiting factor is the amount of graphics memory, you'll easily pass 4GB VRAM usage these days in any game, and when that happens, it all becomes a stuttering mess. Your only solution away from that is to lower image quality settings in-game in the form of AA and texture quality. The good news is that FSR is an option with this card; the bad news is that FSR works better at higher resolutions and not lower ones (like Full HD). Overall we strongly feel that this needs to be a 100-125 USD card, then AMD would have done well. This card, at best, offers reasonable Full HD gaming if the right conditions are met. The Infinity cache (L3) works most of the time; it's designed to be a workaround to fill a massive weakness (the narrow 64-bit memory bus) and the choice of a more affordable memory type (GDDR6 opposed to GDDR6X), this AMD GPU is extremely memory bandwidth deprived, even with GDDR6 at 16 Gbps, due to the 64-bit wide memory bus. And that will bite this product in the ass every time you get GPU limited, or the 16MB L3 cache runs out and gets fewer cache hits.

Performance spread reference

Check out the following comparison of different graphics cards in a selected price-performance range. If you do not run into graphics memory limitations, here's where the card sits:

The card competes best with a GTX 1650 and within the brand a Radeon RX 470/480. Thye real clusterfrack is that the older and back then cheaper 5500 XT is already 37% faster. We'd also like to note that when on PCIe Gen 3.0 the x4 lanes limitation will inflict further performance reductions, as shown in the next chapter of this article.

Cooling & acoustic

The Radeon RX 6400 delivers decent cooling performance even under demanding situations, thanks a low TDP and single fan cooling. According to its default configuration, the GPU beneath the hood generates 56W of heat. We're looking at 38 DBa values under load and temperatures in the 70-degree Celsius range, which are fine. FLIR imaging reveals that the card is leaking a bit of heat. But in general, we are really satisfied with what we have observed.

Energy

Heat output and energy consumption are closely related, as (graphics) processors and heat can be perceived as a 1:1 state; 100 Watts in energy consumption approaches close to 100 Watts in heat as output. This is the basis of TDP. We measure 55 Watts of power consumption under load. This is good.

Coil whine

Coil squeal is hardly present on the 6400, just as it is on any other card these days, albeit to a smaller extent than usual. Is it a bothersome annoyance? It is, without a doubt, at a volume that is difficult no concern. This type of noise would be muffled in a closed chassis and fade into the background. With an open chassis, on the other hand, you may hear coil whine/squeal. In some way or another, all graphics cards do this, especially when running at higher frame rates; this can be perceived.

Pricing

The bitter-sweet reality is that the market a year ago, needed cards like the Radeon RX 6400 very much; these are easy-to-fab cards with a low-value bill of materials. AMD is pushing it with 160 USD, but in these times with the current market, it's not an absurd value to ask. The problem then becomes expensive board designs from AIBs and then the asking price of the etailers.

Tweaking

The card is locked against overclocking.

Conclusion

So then, is the Radeon RX 6400 completely disappointing or something the market needs? The answer is not that simple; the card's main limitation is its relatively small 4GB of memory. However, the infinity cache of 16MB does help out here and there. Gaming in Full HD isn't disappointing all the way, but it ain't a lot of performance at hand. Competition-wise, you're looking at a product slightly faster than a GeForce GTX 1650. What I deem to be frustrating is that the RX 5500 released years ago (which was cheaper msrp wise) is almost 40% faster than what this card has to offer. The better offer even would be a Radeon RX 570/580. You can argue the gain of Raytracing, however the RT performance is so bad that it could have easily not been implemented.

I wanted to include the following graph. In FullHD, you'll get around 50 frames per second on average based on common games, yet with proper image quality settings, but that's with the PCIe 4.0 interface connected. The performance will be significantly reduced when compared to the Gen 3.0 bus. The card connects to only x4 PCIe lanes and relies heavily on rBAR, which needs that PCIe bus. The gap can be so significant that we do not recommend using this card on a PC with PCIe Gen 3.0. At $160, the RX 6400 isn't outrageously priced, but the RX 6400's sole probable application would be in a low-profile system where a standard full size would simply not fit. The video engine is old. The RX 6400 supports decoding H.264 (AVC) and H.265 (HEVC). Accelerated video encoding isn't possible. Budget gamers planning to broadcast on Twitch will be disappointed, especially since the GTX 1650 supports both H.264 and H.265 encoding. HTPC users who wish to transcode live feeds won't be happy. While a current compact form factor PC that supports PCIe 4.0 would be necessary to unlock the full potential of the 6400, the system itself would be valuable enough to justify adding a relatively expensive component.