GPUs Hardware Reviews

Red devil with obesity: Powercolor RX Vega64 Red Devil in review

If we were asked for a somewhat eye-catching RX Vega64 and if the range of such cards were not so limited, then the Red Devil from Powercolor would come to mind spontaneously. Because it not only applies quite strongly visually, but also ... Board layout Powercolor also differs somewhat from AMD's reference layout at first glance, but the most important areas were taken over almost 1:1 during the layout. Only for the second BIOS chip and the LED block with DIP switch... We intentionally use the standard BIOS of the card for the benchmarks, because as we will see later, the OC-BIOS buys a completely negligible performance increase due to an almost nonsensical increase in power consumption. Genere... The overall picture does not change much, even if the Vega cards break in a little more in a few games. But then it almost doesn't matter if reference or board partner card. Shared suffering is half suffering, although it is never a real d... Power consumption at different loads The power consumption in the gaming loop is at the measured approx. 283 watts in standard mode about 3 watts above what could be measured with the reference in the default BIOS. This is all the more astonishing because the... Overclocking and undervolting The conventional overclocking by means of an even higher power limit and more clock counteracts the current cooling concept, because the rather quiet cooler gets along quite well with what it has to dismount ex works. More on the other hand... Cooling system and backplate Of course, the generated waste heat is directly related to the recorded power, for which the cooling solution is responsible for optimum dissipation. If you remove the top cover of the cooler, we already see the ... With the Powercolor RX Vega64, the circle of all graphics cards we have tested so far with AMD's Vega chip closes, because there are no more really produced and traded custom designs on the market, you can see from Sapphires Pu...

Board layout

Powercolor also differs somewhat from AMD's reference layout at first glance, but the most important areas were taken over almost 1:1 during the layout. Only for the second BIOS chip and the LED block including the DIP switch was the board actually "extended" upwards.

Powercolor also relies on 6 phases with doubling, resulting in a total of 12 voltage converters for the VDDC and one phase for memory (MVDD). The production of the further auxiliary voltages is also shown in the diagram. Powercolor has also largely adopted what AMD has implemented in the reference for the components. We will deal with the differences in a while.

On the back, in addition to the very tightly equipped base of the package, we see the PWM controller and other components such as the doubler chips, the SMD capacitors for smoothing and other active and passive components as the most obvious part.

Powercolor relies on a total of two external 8-pin jacks for power supply. Since the motherboard slot is about 23-26 watts maximum, these two connections must therefore handle the rest. We will see how much that is later.

GPU Power Supply (VDDC)

As with the reference design, the focus is on the IR35217 from International Rectifier, a dual output digital multi-phase controller that can provide both the six phases for the GPU and a wider phase for memory, which we are about to will come to speak. But back to the GPU and thus to what we see in the schema above as a VDDC block. We count 12 voltage transformer circuits, not six. However, since only six real phases are created, you double each of these phases in order to be able to divide the load into two converter circles per phase.

A total of six IR3598s are used for this so-called doubling, which are located on the back of the board (we remember). In IR recordings, it is also easy to see how the PWM controller in the idle shifts the load back and forth between the individual phases in order to increase efficiency by using only one phase, but in return also a possible and one-sided overload of a permanently burdened individual phase. Since the boards are very similar, we have the video from the test of the Vega Frontier Edition:

 

The actual voltage conversion of each of the twelve converter circuits is performed by an IRF6811 on the high side and an IRF6894 on the low-side, which also contains the required Schottky diode. Both are previously USED by AMD HEXFETs from International Rectifier.

For the coils, Powercolor relies on acceptable and encapsulated ferrite core coils for both the VDDC and the input range in a cup housing made of composite material. For the LC links in the VDDC range (as with AMD's reference) the 190 nH must be sufficient, but the capping of the tips at the two external 12V supply connections is quite generous at 560 nH per coil.

Power supply of the memory (MVDD)

As mentioned briefly, the IR35217 also provides one phase for storage. One phase is sufficient because the memory is much more adequate. The gate-driver CHL815 is back on the back of the board, while an NTMFD 4C85M from ON Semiconductor is used for voltage conversion. This dual N-Channel MOSFET realizes both the high and the low-side.

It is also interesting that Powercolor also generally dispenses with all cup capacitors and only relies on flat SMD caps. The slightly lower capacity can be compensated by simply switching two of these caps in parallel and usually also using the back of the board. A sensible equalization of the thermal hotspots and a larger heat dissipation also have the nice side effect that you can also enter a temperature class lower and thus also save costs. The finance department is certainly equally pleased with this.

The coil is slightly larger this time with 220 nH. At 820 nH, on the other hand, the coils for the significantly slower clocking converters of the other partial voltages are even larger, which, however, also have to handle significantly lower currents (see green markings on the diagram above).

Other voltage converters

The production of VDDCI is not a big item in terms of performance, but it is important. It is used for GPU-internal level transition between the GPU and memory signals, something like the voltage between the memory and the GPU core on the I/O bus. In addition, a constant source for 0.9 volts is generated. There is also a 1.8V source (TTL, GPU GPIO) on the front side. These three voltage converters are equipped almost identically and rely on an MPQ8633, a Synchronous Step-Down Converter from MPS.

Below the GPU you can still find the APL5620 from Anpec for the VPP. This ultra-low dropout chip generates the very low voltage for the PLL range. Also striking are the dual BIOS chips 25Q20xx from Giantec, which are a double SPI flash chip. Powercolor has placed the appropriate switch in addition to the second chip in the extended, upper part of the board.

Below the GPU you can also find the APL5620 from Anpec for the VPP. This ultra-low dropout chip generates the very low voltage for the PLL area (Phase Locked Loop, marked as purple area in the scheme above).

With the HC238A from ON Semiconductor as a de-multiplexer, the "mausekino" is realized for the LED bar, which shows the utilization of the power supply. Nice gimmick, but in intensity almost disturbing. Especially at night. However, you have another DIP switch as an option to completely darken all of them.

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About the author

Igor Wallossek

Editor-in-chief and name-giver of igor'sLAB as the content successor of Tom's Hardware Germany, whose license was returned in June 2019 in order to better meet the qualitative demands of web content and challenges of new media such as YouTube with its own channel.

Computer nerd since 1983, audio freak since 1979 and pretty much open to anything with a plug or battery for over 50 years.

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