PowerColor Radeon RX 7900 GRE Hellhound is the company's second premium custom-design implementation of the RX 7900 GRE, positioned a notch behind the company's Red Devil flagship. The Radeon RX 7900 GRE (Golden Rabbit Edition) started out as a China-exclusive limited edition product to mark the Year of the Rabbit, but found itself growing in importance to AMD in January 2024, with NVIDIA's brisk launches of the GeForce RTX 4070 SUPER. The Radeon RX 7800 XT beats the original RTX 4070 in raster gaming workloads, but NVIDIA plugged this gap with the RTX 4070 SUPER. The RX 7900 GRE had been around since Summer 2023, and so it was a matter of simply pricing it right for the global market, and giving it a wider launch outside China.
There is an interesting story behind the RX 7900 GRE. AMD had designed a compacted version of the Navi 31 package to drive the mobile versions of the RX 7900 series. This package is rumored to be pin-compatible with the Navi 32 package that powers the RX 7800 XT, allowing AMD's add-in board partners to reuse their RX 7800-series PCBs with compacted Navi 31. This package only has pins for a 256-bit memory bus even though the Navi 31 chip is capable of 384-bit, and so the RX 7900 GRE gets 16 GB of GDDR6 memory across this 256-bit memory bus. With the RX 7900 GRE having a similar 260 W total board power to the RX 7800 XT and its 265 W, AMD gets to minimize the R&D costs for its partners by not only letting them reuse the RX 7800 XT PCB, but also carry over cooling solutions from their RX 7800 XT products.
Navi 31 is a chiplet-based GPU. AMD identified components on the GPU that tangibly benefit from the switch to the newer 5 nm EUV foundry node—basically the GPU's front-end and shader engines, or all its logic-heavy components; and clumped them into a large central chiplet called the graphics compute die (GCD). All the memory-heavy components that don't benefit as much from 5 nm, namely the memory controllers and the Infinity Cache, have been disaggregated to smaller chiplets called the memory cache dies (MCDs), built on the older 6 nm process. Each MCD has a 16 MB segment of the Infinity Cache, and a 64-bit portion of the memory bus. There are six of these on the Navi 31 (96 MB cache, 384-bit memory bus), and four on the Navi 32 (64 MB cache, 256-bit memory bus). On the RX 7900 GRE, AMD enabled four of these MCDs.
The RX 7900 GRE has been carved out of the Navi 31 silicon by not just disabling two of its six MCDs, but also enabling just 80 out of the 96 compute units, for 5,120 stream processors, 160 AI accelerators, 80 Ray accelerators, 320 TMUs, and 160 out of the 192 available ROPs. The GPU is clocked at 1880 MHz Game clock, which PowerColor has further overclocked; while the memory, interestingly, ticks at 18 Gbps, which is slower than the 19.5 Gbps of the RX 7800 XT. At 18 Gbps, the GPU enjoys 576 GB/s of bandwidth.
The underlying graphics architecture is AMD's latest RDNA 3, which the company engineered to take advantage of the 5 nm process. The new dual instruction issue rate compute unit comes with a 17% IPC increase over the RDNA 2 compute unit, and supports newer AI-relevant instructions. The AI accelerator prepares matrix math for execution on the stream processors, providing a large speedup in AI DNN building and training. The 2nd generation Ray accelerator comes with a 50% improvement in ray intersection performance. The new multi-draw indirect accelerator (MDIA) is an exotic new on-silicon accelerator that can significantly speed up Direct3D 12 workloads that use MDI instructions.
The PowerColor RX 7900 GRE Hellhound looks very similar to the company's RX 7800 XT GRE, as it's mostly reusing the board design. The large aluminium fin-stack heatsink uses a trio of LED illuminated fans, while enthusiasts can benefit from features such as dual-BIOS. The card comes with a healthy factory overclock of 2013 MHz Game clock (vs. 1880 MHz reference), while leaving the memory speed untouched. PowerColor is pricing the RX 7900 GRE at $580, a slight premium over the $550 AMD baseline.
Short 10-Minute Video Summary Comparing 6x RX 7900 GRE
Our goal with the videos is to create short summaries, not go into all the details and test results, which can be found in this written review.
AMD Radeon RX 7900 GRE Super Market Segment Analysis
Price
Cores
ROPs
Core Clock
Boost Clock
Memory Clock
GPU
Transistors
Memory
RTX 3070
$310
5888
96
1500 MHz
1725 MHz
1750 MHz
GA104
17400M
8 GB, GDDR6, 256-bit
RTX 3070 Ti
$350
6144
96
1575 MHz
1770 MHz
1188 MHz
GA104
17400M
8 GB, GDDR6X, 256-bit
RX 6800
$450
3840
96
1815 MHz
2105 MHz
2000 MHz
Navi 21
26800M
16 GB, GDDR6, 256-bit
RX 7700 XT
$430
3456
96
2171 MHz
2544 MHz
2250 MHz
Navi 32
26500M
12 GB, GDDR6, 192-bit
RX 6800 XT
$500
4608
128
2015 MHz
2250 MHz
2000 MHz
Navi 21
26800M
16 GB, GDDR6, 256-bit
RTX 3080
$450
8704
96
1440 MHz
1710 MHz
1188 MHz
GA102
28000M
10 GB, GDDR6X, 320-bit
RTX 4070
$525
5888
64
1920 MHz
2475 MHz
1313 MHz
AD104
35800M
12 GB, GDDR6X, 192-bit
RX 7800 XT
$500
3840
96
2124 MHz
2430 MHz
2425 MHz
Navi 32
28100M
16 GB, GDDR6, 256-bit
RX 6900 XT
$650
5120
128
2015 MHz
2250 MHz
2000 MHz
Navi 21
26800M
16 GB, GDDR6, 256-bit
RX 6950 XT
$630
5120
128
2100 MHz
2310 MHz
2250 MHz
Navi 21
26800M
16 GB, GDDR6, 256-bit
RTX 3090
$800
10496
112
1395 MHz
1695 MHz
1219 MHz
GA102
28000M
24 GB, GDDR6X, 384-bit
RTX 4070 Super
$590
7168
80
1980 MHz
2475 MHz
1313 MHz
AD104
35800M
12 GB, GDDR6X, 192-bit
RX 7900 GRE
$550
5120
160
1880 MHz
2245 MHz
2250 MHz
Navi 31
57700M
16 GB, GDDR6, 256-bit
PowerColor RX 7900 GRE Hellhound
$580
5120
160
2013 MHz
2366 MHz
2250 MHz
Navi 31
57700M
16 GB, GDDR6, 256-bit
RTX 4070 Ti
$720
7680
80
2310 MHz
2610 MHz
1313 MHz
AD104
35800M
12 GB, GDDR6X, 192-bit
RTX 4070 Ti Super
$800
8448
112
2340 MHz
2610 MHz
1313 MHz
AD103
45900M
16 GB, GDDR6X, 256-bit
RX 7900 XT
$700
5376
192
2000 MHz
2400 MHz
2500 MHz
Navi 31
57700M
20 GB, GDDR6, 320-bit
RTX 3090 Ti
$1050
10752
112
1560 MHz
1950 MHz
1313 MHz
GA102
28000M
24 GB, GDDR6X, 384-bit
RTX 4080
$1200
9728
112
2205 MHz
2505 MHz
1400 MHz
AD103
45900M
16 GB, GDDR6X, 256-bit
RTX 4080 Super
$1300
10240
112
2295 MHz
2550 MHz
1438 MHz
AD103
45900M
16 GB, GDDR6X, 256-bit
RX 7900 XTX
$910
6144
192
2300 MHz
2500 MHz
2500 MHz
Navi 31
57700M
24 GB, GDDR6, 384-bit
RTX 4090
$1850
16384
176
2235 MHz
2520 MHz
1313 MHz
AD102
76300M
24 GB, GDDR6X, 384-bit
Packaging
The Card
The PowerColor HellHound uses a mostly-black color theme, with some silvery highlights around the fans, paired with transparent fan blades. Both the cooler shroud and backplate are made from metal.
Dimensions of the card are 32.0 x 13.0 cm, and it weighs 1260 g.
Installation requires three slots in your system.
Display connectivity includes three standard DisplayPort 2.1 ports (RDNA 2 had 1.4a) and one HDMI 2.1a (same as RDNA 2).
AMD has upgraded their encode/decode setup. It now comes with two independent hardware units that can encode and decode two streams of video in parallel, or one stream at double the FPS rate. There's support for VP9, H.264, H.265 and AV1 decode, and encoding is supported for H.264, H.265 and AV1.
The card uses a classic dual 8-pin plus PCIe slot power input config, rated for 375 W maximum power. NVIDIA on the other hand uses the new 12+4 pin ATX 12V-2x6 connector, which is rated for up to 600 W of power draw. Right next to the power inputs, there's a physical switch that lets you shut off the RGB lighting—without any software installation required.
The card comes with fixed-color lighting on the front and back, which can be changed between blue and purple, or turned off.
PowerColor has equipped their Hellhound with a dual BIOS feature, the second BIOS lets you enable a "quiet" mode that runs the fans at reduced fan speed for improved acoustics.
Teardown
The main heatsink uses five heatpipes. It also provides cooling for the memory chips and VRM circuitry.
The backplate is made of metal and protects the card against damage during installation and handling.
High-resolution PCB Pictures
These pictures are for the convenience of volt modders and people who would like to see all the finer details on the PCB. Feel free to link back to us and use these in your articles, videos or forum posts.
High-resolution versions are also available (front, back).
Circuit Board (PCB) Analysis
GPU voltage is a 12-phase design, managed by a Monolithic Power Systems MP2857 controller.
Monolithic MP87997 DrMOS components are used for GPU voltage; they are rated for 70 A of current each.
Memory voltage is a 2+1-phase design, managed by two Monolithic Power Systems MP2856 controllers.
For memory, Monolithic MP87995 DrMOS with a 70 A rating are used here, too.
The GDDR6 memory chips are made by Samsung and carry the model number K4ZAF325BC-SC20. They are specified to run at 2500 MHz (20 Gbps effective).
The GPU chip on the Radeon RX 7900 GRE is Navi 31, but it looks quite different to the chips on the RX 7900 XT and XTX. The physical size of the package is reduced, due to its roots in the mobile space. You still get the full-size GCD (graphics compute die) in the center, surrounded by four MCD (memory cache dies). The other two MCDs that you see pictured are non-functional dummies that are used to ensure structural stability of the chip, when a cooler is pushing down on it. While they look similar, the MCDs are not HBM chips. The MCDs are fabricated on a 6 nm process at TSMC Taiwan with a die size of 36.6 mm² each, the GCD is fabricated using TSMC's 5 nanometer node, with a die size of 300 mm². The combined transistor count of the GPU is 57.7 billion.