AMD Radeon Pro 455 vs AMD Radeon Pro 555X Comparison

The AMD Radeon Pro 555X and AMD Radeon Pro 455 are both end-of-life mobile graphics solutions built on the same GCN 4.0 architecture, but benchmark results show they are not interchangeable. The newer 555X wins two of three head-to-head tests, yet the older 455 takes a commanding lead in the Metal API, making the choice highly dependent on the workload. The data shows a split decision: the 555X dominates in OpenCL and Vulkan, while the 455 is the clear winner for Metal-based applications.

Head-to-Head Benchmarks

The Geekbench results reveal a clear performance split between the two GPUs. In the geekbench_metal test, the AMD Radeon Pro 455 scores 15,916 points, which is 9% higher than the 555X’s 14,479 points. This is a significant margin for the older card, suggesting that Metal-optimized applications will run noticeably better on the 455. The 555X cannot match this, and the 9% delta is the largest gap in either direction across all three tests.

The situation reverses in geekbench_opencl. Here, the AMD Radeon Pro 555X delivers a score of 12,628, which is 22.2% ahead of the 455’s 10,336 points. This is the biggest win for either GPU in the entire comparison, indicating that OpenCL compute workloads will strongly favor the 555X. The 22.2% advantage is substantial and shows a major architectural or clock-speed benefit for the newer part in this API.

In geekbench_vulkan, the 555X again comes out on top, scoring 12,855 versus the 455’s 12,240 points. The 5% delta is more modest than the OpenCL gap, but it still represents a consistent win for the 555X. Across the three tests, the 555X claims two victories, while the 455 secures one. The average benchmark score reinforces this: the 555X averages 13,321 points, placing it in the 54th percentile of all GPUs, while the 455 averages 12,831 points, landing in the 52nd percentile.

Looking at the nearest rivals provides context for these scores. The 555X’s average score is nearly identical to the NVIDIA GeForce GTX 480 (13,300, a 0.2% delta) and the AMD FirePro M6100 (13,354, a -0.2% delta). The 455’s average is essentially tied with the NVIDIA GeForce GTX 590 (12,830, 0% delta) and slightly below the AMD FirePro W5100 (12,847, a -0.1% delta). This places both cards in a similar performance tier, but the 555X holds a roughly 3.8% overall average score advantage over the 455.

Architecture Differences

Both GPUs share the same fundamental architecture: GCN 4.0, built on a 14 nm process at GlobalFoundries. They also have identical core configurations, with 768 shading units, 48 texture mapping units, and 16 raster operation units. The transistor count is the same at 3,000 million, and the die size is identical at 123 mm², yielding the same transistor density of 24.4M per mm². Neither card features ray tracing or tensor cores, and both support DirectX 12 (12_0), OpenGL 4.6, and Vulkan 1.3.

The key architectural differences lie in clock speeds, memory, and power. The 555X runs its memory at 1470 MHz with 5.9 Gbps effective speed, while the 455 runs at 1270 MHz with 5.1 Gbps effective speed. This directly impacts memory bandwidth: the 555X delivers 94.08 GB/s, whereas the 455 provides 81.28 GB/s, a 12.8 GB/s difference. The 555X also has double the memory capacity at 4 GB, compared to the 455’s 2 GB, though both use GDDR5 on a 128-bit bus.

Compute rates follow the clock advantage. The 555X achieves a pixel rate of 14.51 GPixel/s and a texture rate of 43.54 GTexel/s, while the 455 reaches 13.68 GPixel/s and 41.04 GTexel/s. Floating-point performance shows a similar pattern: the 555X delivers 1,393.2 GFLOPS for both FP32 and FP16 (at a 1:1 ratio), while the 455 offers 1,313.3 GFLOPS for both. The 555X’s higher memory clocks and 4 GB frame buffer make it the more capable part for texture-heavy and high-resolution workloads, despite the identical shader core layout.

Power consumption differs significantly. The 555X has a TDP of 75 W, while the 455 is rated at just 35 W. This is a major consideration for mobile systems, as the 455 will generate less heat and consume less power. The 555X is classified as an IGP (integrated graphics processor), while the 455 is an MXM Module, indicating different physical form factors. Both use a PCIe 3.0 x8 interface and have no power connectors, with display outputs described as portable device dependent.

FAQ

Q: Which GPU is faster in Metal-based applications?

A: The AMD Radeon Pro 455 is 9% faster in the geekbench_metal test, scoring 15,916 points compared to the 555X’s 14,479 points.

Q: How much better is the 555X in OpenCL workloads?

A: The 555X leads by 22.2% in geekbench_opencl, with a score of 12,628 versus the 455’s 10,336 points.

Q: Do both GPUs have the same number of shading units?

A: Yes, both feature 768 shading units, along with 48 texture mapping units and 16 raster operation units.

Q: What is the memory capacity difference?

A: The 555X has 4 GB of GDDR5 memory, while the 455 has 2 GB. Both use a 128-bit bus, but the 555X offers higher bandwidth at 94.08 GB/s versus 81.28 GB/s.

Q: Which card has a lower power draw?

A: The 455 has a TDP of 35 W, which is less than half of the 555X’s 75 W rating.

Q: Are the architectures identical?

A: Both use GCN 4.0 on a 14 nm process, with the same transistor count and die size. The differences are in clock speeds, memory, and power envelope.

The Verdict

The data points to a clear split based on API preference. For users primarily running Metal-based applications, the AMD Radeon Pro 455 is the better choice, as its 9% lead in geekbench_metal is decisive. This makes the 455 the practical pick for macOS-centric workflows that leverage Metal for rendering or compute.

However, for OpenCL or Vulkan workloads, the AMD Radeon Pro 555X is the superior option. Its 22.2% OpenCL advantage and 5% Vulkan lead make it the stronger all-around performer for general compute and cross-platform tasks. The 555X also offers double the memory (4 GB vs 2 GB) and higher bandwidth, which is critical for modern games and large datasets.

The 555X’s higher TDP of 75 W versus 35 W is a trade-off: it delivers more performance but at the cost of greater power consumption and heat. The 455’s lower power draw makes it more suitable for thin-and-light systems where thermals are a constraint. Ultimately, the 555X is the better all-rounder for performance, while the 455 wins specifically in Metal and efficiency.

Specification Differences

• Memory Size: 4 GB (555X) vs 2 GB (455)
• Memory Clock: 1470 MHz / 5.9 Gbps effective (555X) vs 1270 MHz / 5.1 Gbps effective (455)
• Memory Bandwidth: 94.08 GB/s (555X) vs 81.28 GB/s (455)
• Pixel Rate: 14.51 GPixel/s (555X) vs 13.68 GPixel/s (455)
• Texture Rate: 43.54 GTexel/s (555X) vs 41.04 GTexel/s (455)
• FP32 Performance: 1,393.2 GFLOPS (555X) vs 1,313.3 GFLOPS (455)
• FP16 Performance: 1,393.2 GFLOPS (555X) vs 1,313.3 GFLOPS (455)
• TDP: 75 W (555X) vs 35 W (455)
• Slot Width: IGP (555X) vs MXM Module (455)
• Release Date: 2018-07-15 (555X) vs 2016-10-29 (455)

Where Each One Wins

The AMD Radeon Pro 555X wins in raw compute and memory-heavy scenarios. Its 22.2% OpenCL lead is the standout advantage, making it the go-to for OpenCL-based rendering, physics simulation, or data processing. The 5% Vulkan win also positions it better for modern cross-platform games and Vulkan-optimized applications. The 4 GB frame buffer and 94.08 GB/s bandwidth give it headroom for higher-resolution textures and larger working sets, which is a practical benefit for content creation.

The AMD Radeon Pro 455 wins in Metal-specific environments and efficiency. Its 9% Metal lead means macOS apps that use Metal will run faster, making it the preferable option for users locked into Apple’s ecosystem. The 35 W TDP is a major advantage for battery life and thermal management in portable devices. For users who prioritize lower power draw and Metal performance over raw compute, the 455 is the sensible pick.

In summary, the 555X is the performance leader with 2 wins out of 3 benchmarks and a higher average score (13,321 vs 12,831). The 455 is the efficiency and Metal specialist, offering a compelling option for specific use cases. Choose the 555X for OpenCL/Vulkan and memory capacity; choose the 455 for Metal and power efficiency.