AMD Radeon Pro 555 vs AMD Radeon Pro 555X Comparison

The AMD Radeon Pro 555 and the AMD Radeon Pro 555X are two closely related integrated GPUs from the Radeon Pro Mac series, both built on the same Polaris 21 chip. Despite sharing a common foundation and both holding the 54th percentile ranking among all GPUs, benchmark data reveals a split personality: the Pro 555 wins decisively in Metal performance while the Pro 555X counters with wins in OpenCL and Vulkan. The average benchmark scores are nearly identical, with the Pro 555 at 13,407 and the Pro 555X at 13,321, a difference of less than one percent, yet the individual test results show distinct strengths that define their respective use cases.

Head-to-Head Benchmarks

The most striking divergence between the two GPUs appears in the Geekbench Metal test. Here, the AMD Radeon Pro 555 scores 16,236 against the Pro 555X's 14,479, giving the original card a 12.1% advantage. This is the largest margin in any benchmark between the two, and it stands out because it reverses the expected hierarchy based on clock speeds and memory bandwidth. The Pro 555X's higher specifications do not translate into Metal performance; in fact, the data indicates the older card holds a substantial lead in this API.

The situation flips entirely in the Geekbench OpenCL test. The Pro 555X posts a score of 12,628, beating the Pro 555's 11,682 by 7.5%. This result aligns more closely with the hardware specifications, as the Pro 555X carries higher memory clocks and more VRAM. The Vulkan test shows a similar but narrower pattern: the Pro 555X scores 12,855 versus the Pro 555's 12,303, a 4.3% advantage for the newer part.

Counting the wins, the Pro 555X takes two of three benchmarks, while the Pro 555 takes one. However, the magnitude of the Pro 555's Metal victory is greater than either of the Pro 555X's wins individually. The average benchmark score calculation smooths out these swings: the Pro 555 averages 13,407, while the Pro 555X averages 13,321, meaning the Pro 555 is effectively 0.6% ahead on aggregate despite losing two tests. This suggests that the Metal workload, where the Pro 555 excels, carries significant weight in the overall scoring, or that the Pro 555X's OpenCL and Vulkan advantages are not large enough to overcome the Metal deficit.

Where Each One Wins

The data points to a clear API-based split in strengths. The AMD Radeon Pro 555 is the superior choice for Metal-centric workloads, which are common in macOS applications and creative software that leverage Apple's graphics framework. With a 12.1% lead in Geekbench Metal, this GPU is positioned as the stronger option for tasks that rely on that API, such as video editing, compositing, and certain 3D rendering pipelines that favor Metal optimization.

Conversely, the AMD Radeon Pro 555X wins in OpenCL and Vulkan, making it the more versatile card for cross-platform compute tasks. The 7.5% OpenCL advantage and the 4.3% Vulkan advantage indicate that the Pro 555X handles general-purpose GPU compute and Vulkan-based games or applications more effectively. For users running Linux or Windows environments where Vulkan is prevalent, or for compute workloads using OpenCL libraries, the Pro 555X would be the preferred option. The Pro 555X's higher memory bandwidth and capacity support these compute-oriented tasks, even if that hardware advantage does not translate to Metal.

Architecture Differences

Both GPUs share the same fundamental architecture: GCN 4.0, manufactured on a 14 nm process at GlobalFoundries. Each uses the Polaris 21 chip with 3,000 million transistors on a 123 mm² die, yielding a transistor density of 24.4 million per square millimeter. The core configuration is identical, with 768 shading units, 48 texture mapping units, and 16 raster operation pipelines. Neither GPU features dedicated ray tracing or tensor cores, and both support DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3.

The architectural differences are minimal, but the memory subsystem reveals the key divergence. The Pro 555 operates with 2 GB of GDDR5 memory at an effective speed of 5.1 Gbps, while the Pro 555X doubles the capacity to 4 GB and raises the effective speed to 5.9 Gbps. Both use a 128-bit memory bus, but the higher clock rate on the Pro 555X results in a bandwidth of 94.08 GB/s versus the Pro 555's 81.60 GB/s. This 15% bandwidth advantage, combined with double the VRAM capacity, is the primary architectural distinction between the two parts. The compute rates follow accordingly: the Pro 555X achieves 1,393.2 GFLOPS FP32 and FP16 (1:1), while the Pro 555 delivers 1,305.6 GFLOPS in both precision modes. Pixel and texture rates are similarly higher on the Pro 555X, at 14.51 GPixel/s and 43.54 GTexel/s respectively, versus 13.60 GPixel/s and 40.80 GTexel/s on the Pro 555.

Specification Differences

The specification sheet shows a handful of fields where the two cards diverge, all stemming from the memory configuration and resulting clock rates. The memory clock is listed as 1275 MHz with 5.1 Gbps effective for the Pro 555, while the Pro 555X runs at 1470 MHz with 5.9 Gbps effective. Memory size is the most obvious difference: 2 GB on the Pro 555 versus 4 GB on the Pro 555X. This leads to a bandwidth gap of 81.60 GB/s versus 94.08 GB/s.

The compute specifications scale with these memory changes. Pixel rate increases from 13.60 GPixel/s on the Pro 555 to 14.51 GPixel/s on the Pro 555X. Texture rate rises from 40.80 GTexel/s to 43.54 GTexel/s. FP32 and FP16 performance both move from 1,305.6 GFLOPS on the Pro 555 to 1,393.2 GFLOPS on the Pro 555X. Notably, the power consumption remains identical at 75 W TDP, and both cards are integrated into the system (IGP slot width) with no power connectors required. The bus interface is PCIe 3.0 x8 for both, and display outputs are portable device dependent for both. Release dates differ, with the Pro 555 launching on June 4, 2017, and the Pro 555X following on July 15, 2018, but both are now end-of-life products.

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon Pro 555 has a higher average benchmark score of 13,407, compared to the AMD Radeon Pro 555X's 13,321. This is a difference of approximately 0.6%.

Q: How does the Pro 555X perform in Metal compared to the Pro 555?

A: The Pro 555X is 12.1% slower than the Pro 555 in the Geekbench Metal test. The Pro 555 scores 16,236, while the Pro 555X scores 14,479.

Q: What is the memory capacity difference between the two cards?

A: The AMD Radeon Pro 555 has 2 GB of GDDR5 memory, while the AMD Radeon Pro 555X has 4 GB of GDDR5 memory. Both use a 128-bit memory bus.

Q: In which benchmark does the Pro 555X have its largest margin of victory?

A: The Pro 555X's largest margin of victory is in Geekbench OpenCL, where it scores 12,628 against the Pro 555's 11,682, a 7.5% advantage.

Q: Do both GPUs support the same APIs?

A: Yes, both the AMD Radeon Pro 555 and the AMD Radeon Pro 555X support DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3.

Q: What is the power consumption of each GPU?

A: Both the AMD Radeon Pro 555 and the AMD Radeon Pro 555X have a TDP of 75 W, and neither requires external power connectors.

The Verdict

The benchmark data presents a nuanced picture that defies a simple "newer is better" conclusion. For users prioritizing Metal performance, the AMD Radeon Pro 555 is the clear choice. Its 12.1% lead in Geekbench Metal is substantial and directly relevant to macOS-centric creative workflows. The fact that it achieves this despite lower memory clocks and half the VRAM of its successor indicates that software optimization or driver maturity favors the older part in this specific API.

For users working in OpenCL or Vulkan environments, the AMD Radeon Pro 555X offers measurable improvements. The 7.5% OpenCL advantage and 4.3% Vulkan advantage, combined with double the VRAM capacity and 15% higher memory bandwidth, make it the better option for compute-heavy tasks and cross-platform graphics workloads. The higher FP32 throughput of 1,393.2 GFLOPS versus 1,305.6 GFLOPS also supports this direction.

Ultimately, the choice hinges on the primary API of the user's applications. The Pro 555 wins where Metal matters; the Pro 555X wins everywhere else. Since both cards sit at the 54th performance percentile and have nearly identical average scores, neither holds a decisive overall advantage. The Pro 555X's additional VRAM and bandwidth make it the more future-proof option for handling larger textures and datasets, while the Pro 555's Metal dominance suggests it may be better tuned for Apple's graphics stack. Users should match the GPU to their software environment rather than relying on generational naming conventions.