The AMD Radeon HD 7850 (Cont’d)
Contents
The Radeon HD 7850 uses a cooling solution identical to the one used on the Radeon HD 7870 GHz Edition, with a heatsink with aluminum fins, copper base, two 5 mm heatpipes and one 7 mm heatpipe, cooled by a 74 mm radial fan.
Figure 5: Heatsink
Figure 6: Heatsink
In Figure 7, you can see the video card with its cooler removed. The printed circuit board used on the Radeon HD 7850 is identical to the one used on the Radeon 7870 GHz Edition. The only difference between the two is the number of power connectors (two on the Radeon HD 7870 and one on the Radeon HD 7850) and the number of phases on the GPU voltage regulator. While the Radeon HD 7870 GHz Edition uses a five-phase voltage regulator, the Radeon HD 7850 uses a circuit with four phases. The voltage regulator circuit uses a digital design and is controlled by a CHiL CHL8225G chip, with each phase driven by a Renesas R2J20658BNP (“DrMOS”) chip, which incorporates the three required transistors (“high side,” “low side,” and “driver”) and can switch at higher frequencies and provide higher efficiency. All coils use ferrite cores and all capacitors are solid.
Figure 7: AMD Radeon HD 7850
Figure 8: Main voltage regulator
The reviewed video card uses eight Hynix H5GQ2H24MFR-T2C GDDR5 chips, each one storing 2 Gbit of data, making the 2 GB of memory available on this video card. Each chip is connected to the GPU through a 32-bit lane, creating the 256-bit datapath that is available. These chips can run up to 5 GHz. On this video card, they are accessed at 4.8 GHz, leaving a small 4% margin for you to increase the memory clock still within specifications. Of course, you can always try to push the memory clock above its specs.
This is the same configuration used on the Radeon HD 7870 GHz Edition.
Figure 9: Memory chips
Before seeing the performance results, let’s recap the main features of this video card.
