AMD Radeon HD 7770M vs AMD Radeon Pro 555X Comparison

The Verdict

The benchmark data presents a clear, if narrow, hierarchy between these two AMD mobile GPUs. The AMD Radeon Pro 555X is the faster part in the only directly comparable test, winning the Geekbench Metal head-to-head with a score of 14479 against the HD 7770M's 13536, a decisive 6.5% advantage. However, the broader picture is more nuanced. Looking at each card's average benchmark score across all available tests, the HD 7770M actually posts a higher average (13536) than the Pro 555X (13321). This is because the Pro 555X's average is dragged down by its OpenCL and Vulkan scores (12628 and 12855, respectively), which are lower than its Metal result. The data suggests the Pro 555X is the better choice for Metal-accelerated applications, while the HD 7770M holds its own when considering a wider range of compute workloads. For a user strictly focused on Metal performance, the Pro 555X is the pick. For those looking at general compute across multiple APIs, the HD 7770M's consistency is notable, even though it is built on older technology.

Architecture Differences

The two GPUs come from different generations of AMD's Graphics Core Next (GCN) architecture, which explains their differing feature sets and capabilities. The HD 7770M is based on the "Chelsea" chip and utilizes the original GCN 1.0 architecture. It was manufactured on a 28 nm process at TSMC, packing 1,500 million transistors into a 123 mm² die. This results in a transistor density of 12.2 million transistors per square millimeter. Its API support includes DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170.

In contrast, the Radeon Pro 555X is built on the "Polaris 21" chip and uses the much newer GCN 4.0 architecture. It is fabricated on a more advanced 14 nm process at GlobalFoundries and contains a significantly higher 3,000 million transistors, also on a 123 mm² die. This doubles the transistor density to 24.4 million transistors per square millimeter. The Pro 555X supports a newer DirectX 12 (12_0) feature level and a newer Vulkan version (1.3), while keeping OpenGL 4.6 support. The architectural leap from GCN 1.0 to GCN 4.0 brings with it the higher transistor count, which is fundamental to the Pro 555X's higher core counts and performance capabilities. The foundry change from TSMC to GlobalFoundries and the node shrink from 28 nm to 14 nm are the physical basis for these improvements.

Head-to-Head Benchmarks

The only directly comparable benchmark between the two cards is Geekbench Metal, and the results are unambiguous. The AMD Radeon Pro 555X wins with a score of 14479, outperforming the AMD Radeon HD 7770M's score of 13536 by 6.5%. This is a substantial margin for a single-generation comparison, showing the Pro 555X's newer architecture and higher specifications translate into a real-world performance lead in Apple's Metal API.

The deltaPct of -6.5% from the perspective of the HD 7770M indicates it trails the Pro 555X by that margin. While this is the only head-to-head test, it is a meaningful one. The HD 7770M does not have a score in the other two tests that the Pro 555X has (OpenCL and Vulkan), so a direct comparison in those workloads is not possible from the data. However, looking at the Pro 555X's own scores, its Metal result (14479) is significantly higher than its OpenCL (12628) and Vulkan (12855) scores. This suggests that the Pro 555X is particularly well-optimized for Metal, and its advantage over the HD 7770M might not be as large, or could even reverse, in other APIs where the HD 7770M's average score (13536) is higher than the Pro 555X's OpenCL and Vulkan results.

FAQ

Q: Which GPU is faster in the Geekbench Metal benchmark?

A: The AMD Radeon Pro 555X is faster. It scores 14479, which is 6.5% higher than the AMD Radeon HD 7770M's score of 13536.

Q: How do their average benchmark scores compare across all tests?

A: The AMD Radeon HD 7770M has a higher average benchmark score of 13536, compared to the AMD Radeon Pro 555X's average of 13321. This is because the Pro 555X's average includes lower scores from OpenCL and Vulkan tests.

Q: What are the key differences in their process nodes and transistor counts?

A: The AMD Radeon HD 7770M uses a 28 nm process at TSMC and contains 1,500 million transistors. The AMD Radeon Pro 555X uses a smaller 14 nm process at GlobalFoundries and contains double the transistors at 3,000 million.

Q: Do they have the same amount of video memory?

A: No. The AMD Radeon HD 7770M has 1024 MB of GDDR5 memory, while the AMD Radeon Pro 555X has 4 GB of the same memory type.

Q: Which card has a higher memory bandwidth?

A: The AMD Radeon Pro 555X has a higher memory bandwidth of 94.08 GB/s, compared to the AMD Radeon HD 7770M's 64.00 GB/s. This is due to the Pro 555X's faster memory clock of 1470 MHz versus 1000 MHz.

Q: How do their power requirements differ?

A: The AMD Radeon HD 7770M has a much lower TDP of 32 W, while the AMD Radeon Pro 555X has a TDP of 75 W. The Pro 555X is an integrated graphics processor (IGP) with no power connectors, while the HD 7770M's power connector setup is listed as portable device dependent.

Where Each One Wins

The data points to distinct scenarios where each GPU is preferable. The AMD Radeon Pro 555X is the clear winner in any workload that leverages the Metal graphics API. Its head-to-head victory in Geekbench Metal, with a 6.5% lead, makes it the superior choice for Metal-based games and professional applications. The Pro 555X also wins on raw specifications that translate to compute and texture work: it has 768 shading units and 48 texture mapping units (TMUs), compared to the HD 7770M's 512 shading units and 32 TMUs. This gives it a significantly higher texture rate of 43.54 GTexel/s versus 21.60 GTexel/s, and a higher pixel rate of 14.51 GPixel/s versus 10.80 GPixel/s. Its FP32 compute rating of 1,393.2 GFLOPS is double the HD 7770M's 691.2 GFLOPS, and it even offers FP16 performance at a 1:1 ratio (1,393.2 GFLOPS), a feature the HD 7770M lacks.

The AMD Radeon HD 7770M, while losing the direct Metal test, shows its strengths in a different light. Its average benchmark score of 13536 is higher than the Pro 555X's average of 13321, indicating more consistent performance across different compute APIs when the Pro 555X's OpenCL and Vulkan scores are considered. For users running a mix of OpenCL and Vulkan workloads, the HD 7770M's performance profile is more balanced. It also achieves this with a dramatically lower TDP of 32 W versus 75 W, making it a vastly more power-efficient part. The HD 7770M is also the only one of the two with a known production status of "End-of-life" and a release date in 2012, while the Pro 555X was released in 2018, making the HD 7770M a potentially interesting option for legacy systems where power draw is a primary constraint.

Specification Differences

The specification sheets for these two GPUs reveal the full extent of their generational gap. The most obvious difference is in the core configuration. The AMD Radeon Pro 555X has 768 shading units and 48 TMUs, while the AMD Radeon HD 7770M has 512 shading units and 32 TMUs. Both have 16 ROPs. This difference in shading units and TMUs directly contributes to the Pro 555X's higher pixel rate (14.51 GPixel/s vs 10.80 GPixel/s) and texture rate (43.54 GTexel/s vs 21.60 GTexel/s). The FP32 compute output is also double, with the Pro 555X achieving 1,393.2 GFLOPS compared to 691.2 GFLOPS. The Pro 555X also lists FP16 performance at 1,393.2 GFLOPS (1:1), a capability not listed for the HD 7770M.

Memory configuration also differs significantly. The Pro 555X has 4 GB of GDDR5 memory, while the HD 7770M has only 1024 MB. Both use a 128-bit memory bus, but the Pro 555X's memory clock is higher at 1470 MHz (5.9 Gbps effective) versus 1000 MHz (4 Gbps effective), resulting in a higher memory bandwidth of 94.08 GB/s compared to 64.00 GB/s. The process node and transistor counts are starkly different: the Pro 555X uses a 14 nm process at GlobalFoundries with 3,000 million transistors, while the HD 7770M uses a 28 nm process at TSMC with 1,500 million transistors. Despite the transistor count doubling, the die size is identical at 123 mm², leading to a higher transistor density for the Pro 555X (24.4M / mm² vs 12.2M / mm²). Power consumption is another major divider, with the Pro 555X rated at 75 W and the HD 7770M at just 32 W. The Pro 555X is classified as an IGP with no power connectors, while the HD 7770M's power connectors are listed as "Portable Device Dependent". Finally, the bus interface differs; the Pro 555X uses PCIe 3.0 x8, while the HD 7770M uses the older PCIe 2.0 x16.