This question which seems a bit strange, actually on this graphics card is quite important. The RX 6400 has a PCIe x4 Setupwhich is part of the usual configuration of gaming graphics cards. The reason for reducing the PCIe lanes used is to simplify the design of the GPU itself.
AMD RX 6400, a simple and, in principle, inexpensive graphics card
The RX 6400 graphics card ranks as the worst in the RX 6000 family based on the RDNA2 architecture. It is geared towards an audience that wants to play casually and doesn’t care about the FPS rate.
This graphics card has 768 stream processors, 12 ray accelerators, 48 texture units and 32 ROPs. The graphics card locks in at a Gaming frequency of 2039 MHz and can reach 2321 MHz in Boost mode. 4 GB GDDR6 at a frequency of 16 GHz, with a 64-bit interface and a bandwidth of 128 GB/s.
This graphics card uses a PCIe 4.0 x4 connection, so it does not use all the pins of this connection interface. A fact that may seem trivial, but which becomes important if we take into account the volume of data that can be transmitted. PCIe 4.0 x4 allows up to 7.88 GB/s of datawhile PCIe 3.0 x4 allows up to 3.94 GB/s of data.
As we can see, we halve the amount of data transmitted. This, of course, will eventually affect performance. The amount of information that can be exchanged with the processor is less and this implies a drop in performance.
How much does the performance of this graphics card degrade?
According to the test carried out by TechPowerUp, a average yield loss of 14%. For the test, 25 different games were tested at 1080p, 1440p, and 2180p resolutions. Obviously, as this graphics card only has 4 GB of VRAM memory, the tests at 1440p and 2180p are quite uninteresting, since the performance will be very low in said resolutions.
The most noticeable performance loss is Assassin’s Creed Valhalla and God of Waror drops up to 35% yield. In DOOM Eternal, you lose up to 30% performance. Note that in some games the difference is virtually imperceptible, hence the general measure of performance loss is 14%.
having low VRAM memory, the operating system frees space by sending the information from the graphics memory to the system’s main memory. When information needs to be retrieved, bandwidth is limited, which has a significant impact on performance.
But with no load on VRAM, the clipped bandwidth is very significant. Rendering plays a big role in things like rendering or how you animate the world. Instructions must travel between the processor and the graphics card. If there is one neck (as it is) latencies increase. As the task execution time increases, the amount of FPS we will see on the screen will be less
So shouldn’t I buy the RX 6400?
It should be noted that this graphics card is a solution designed for simple configurations. It is designed for those who play casually and the amount of FPS is completely the same. Users who want to disconnect after work playing any game. We will be able to move any game without problems, obviously a God of War will cost more than a Fortnite or CS:GO.
You have to be aware that it is a graphics card that has a price of around 200 $, so it is also not required to play 4K @ 60 FPS games, since it is not designed for that. Simply, we must know that with the PCIe 3.0 interface it will have worse performance in some games than if we install it in a system with PCIe 4.0.
