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It’s time to talk more about the AMD Radeon RX 6800 graphics card, which often flashed in our latest reviews. This is the junior model based on the Navi 21 GPU, which combines all the advantages of the RDNA 2 architecture with fewer compute units, more memory and a lower price. We will look at the features of the reference AMD Radeon RX 6800 video card, evaluate its overclocking potential, and compare it with the GeForce RTX 3070 and older video cards.
If we compare the Radeon RX 6800 with the Radeon RX 6800 XT, then the younger solution is cut by 20% in terms of the number of active computing units. The Radeon RX 6800 has 3840 stream processors with 240 texture units and 60 trace processing cores with 96 ROPs. Reduced GPU frequencies — Game Clock is set at 1815 MHz with Boost Clock 2105 MHz, while the Radeon RX 6800 XT has 2015 MHz and 2250 MHz. But they still use 16 GB of GDDR6 video memory, which is a lot compared to competitors from NVIDIA. The effective memory frequency is 16 GHz. Cutting the chip and frequencies allowed to reduce the TDP to 250 watts.
| Video adapter | Radeon RX 6800 XT | Radeon RX 6800 |
|---|---|---|
| Core | Navi 21 | Navi 21 |
| Number of transistors, million pieces | 26800 | 26800 |
| Process technology, nm | 7 | 7 |
| Core area, sq. mm | 520 | 520 |
| Number of CUDA Stream Processors | 4608 | 3840 |
| Number of Ray Accelerator cores | 72 | 60 |
| Number of texture blocks | 288 | 240 |
| Number of render units | 128 | 96 |
| Base core frequency, MHz | 1825 | 1700 |
| Game Clock frequency, MHz | 2015 | 1815 |
| Boost frequency, MHz | 2250 | 2105 |
| Memory bus, bit | 256 | 256 |
| Memory type | GDDR6 | GDDR6 |
| Memory frequency, MHz | 16000 | 16000 |
| Memory size, GB | 16 | 16 |
| Supported version of DirectX | 12 Ultimate (12_2) | 12 Ultimate (12_2) |
| Interface | PCI-E 4.0 | PCI-E 4.0 |
| Power, W | 300 | 250 |
The reference Radeon RX 6800 graphics card is visually identical to the XT version, but slightly thinner. Length — incomplete 27 cm. Equipped with a cooling system with three fans. The case is made in black and silver colors.
The side face of the case has a red edging and a red illuminated Radeon logo. In the corner there are two power connectors with eight pins.
The reverse side is completely covered with a metal plate.
The thickness of the video card does not exceed two slots, which is the main structural difference from the Radeon RX 6800 XT. The rear panel has HDMI ports, two Display Ports and Virtual Link Type C.
The cooling design is standard for the reference series RX 6800.
The board is covered by a large plate that removes heat from the power elements. On top of this base is a ribbed heatsink with a protruding pad for the graphics processor.
All elements of the cooling system are black coated.
The heatsink fins are soldered onto a large evaporation chamber, which works on the principle of a large heat pipe. The photo below clearly shows that the main radiator is designed to contact the GPU and memory chips through special areas. Instead of thermal paste for the GPU, a graphene thermal pad is used.
Fans with a diameter of 80 mm are attached to the outer casing.
The blades have a large bend and an outer ring. This design improves airflow.
The backplate is not a heatsink — there are no thermal pads for contact with hot areas of the board. The plate performs a protective function and gives rigidity to the entire structure.
AMD’s Radeon RX 6800 and Radeon RX 6800 XT use the same PCB design.
The GPU is powered by 12 phases.
The Navi 21 chip is surrounded by a massive protective frame. Eight Samsung K4ZAF325BM-HC16 memory chips are soldered around it.
Standard specs call for a base core clock of 1700MHz for the Radeon RX 6800 with a Game Clock of 1815MHz and a Boost Clock of 2150MHz.
In many games, the GPU frequency was close to 2200 MHz, in heavy applications at high resolutions it kept within 2100-2200 MHz. This is illustrated below with MSI Afterburner monitoring screenshots in Horizon Zero Dawn and The Division 2 at 4K resolution.
Peak Boost values are limited to 2259 MHz. The temperature rises easily to 73°C in the open case. The maximum fan speed in this mode reaches 1700 rpm, while the noise is low. But in harsher environments, such as inside a case with poor ventilation, heat and noise will be higher.
As for overclocking, all operations are best done through the built-in functions in the AMD Adrenalin Edition software. Here you can smoothly adjust the GPU frequency range, select lower voltages, set your own fan control algorithm, etc. The settings configuration for our video card is shown below.
Max Boost increased to 2500 MHz at Game Clock 1950 MHz. The memory target frequency is set to 2150 MHz (17200) MHz. Increased fan speed and power limit.
The final GPU frequencies exceeded 2400 MHz. Operating temperatures remained at the initial level with a fan speed of 1950 rpm.
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