AMD Radeon R5 M255 vs NVIDIA Quadro P400 Comparison

AMD Radeon R5 M255 and NVIDIA Quadro P400 are two end-of-life mobile and workstation graphics parts that land within 2.2% of each other in average benchmark score, yet they win in different workloads. The AMD card takes the OpenCL test, while the NVIDIA card wins the Vulkan test, making the choice depend entirely on the application’s API. With a 28th percentile ranking for the R5 M255 and a 27th percentile for the P400, both sit near the bottom of the GPU hierarchy, but their architectural differences explain why each leads in its respective test.

Where Each One Wins

The AMD Radeon R5 M255 claims victory in Geekbench OpenCL, scoring 4650 against the Quadro P400’s 4249 — a 9.4% advantage. This is its stronger workload, and the margin is substantial enough to matter for compute tasks that rely on OpenCL. The R5 M255’s win here is driven by its higher shading unit count (384 vs 256) and its 1:1 FP16 ratio, which gives it 721.9 GFLOPS in both FP16 and FP32, compared to the P400’s 641.0 GFLOPS FP32 and a heavily cut 10.02 GFLOPS FP16 (1:64 ratio). For any OpenCL kernel that uses FP16 or scales with shader throughput, the AMD part is clearly the better choice.

The NVIDIA Quadro P400 takes the Geekbench Vulkan test, scoring 5119 against the R5 M255’s 4925 — a 3.8% lead. This is a narrower margin than AMD’s OpenCL win, but it is consistent with the P400’s more modern Pascal architecture and its Vulkan 1.4 API support, which exceeds the R5 M255’s Vulkan 1.2.170. The P400’s higher pixel rate (20.03 GPixel/s vs 7.52 GPixel/s) and better memory type (GDDR5 vs DDR3) also contribute to its Vulkan performance, even though its raw FP32 is lower. For applications that favor Vulkan, the P400 is the winner, but the gap is modest.

Overall, the data splits cleanly: AMD wins compute-oriented OpenCL, NVIDIA wins modern-graphics Vulkan. Neither card dominates across the board, and the 1-1 win count reflects a genuine trade-off rather than a clear hierarchy.

Architecture Differences

The two GPUs come from different foundries and nodes. AMD’s R5 M255 uses a Topaz chip built on GCN 3.0 architecture, manufactured by TSMC on a 28 nm process. It contains 1,550 million transistors on a 125 mm² die, yielding a transistor density of 12.4M per mm². NVIDIA’s Quadro P400 uses a GP107 chip on Pascal architecture, made by Samsung on a 14 nm process, packing 3,300 million transistors into a 132 mm² die — a density of 25.0M per mm². The P400’s node advantage is clear: nearly double the transistor count in a similar die size, which explains its higher clock speeds and efficiency.

Clocks differ significantly. The R5 M255 runs at 925 MHz base and 940 MHz boost, while the P400 runs at 1228 MHz base and 1252 MHz boost — roughly 300 MHz higher. This clock advantage helps the P400 compensate for its lower shader count. The memory subsystems are also distinct: the R5 M255 uses 2 GB of DDR3 on a 128-bit bus, achieving 32.00 GB/s bandwidth, while the P400 uses 2 GB of GDDR5 on a 64-bit bus, achieving 32.06 GB/s. Despite half the bus width, the P400’s GDDR5 memory provides nearly identical bandwidth, which reflects its faster memory clock (1002 MHz vs 1000 MHz) and effective data rate (4 Gbps vs 2 Gbps).

Core configurations favor AMD in raw count. The R5 M255 has 384 shading units, 24 TMUs, and 8 ROPs, while the P400 has 256 shading units, 16 TMUs, and 16 ROPs. The P400’s higher ROP count (double) gives it a massive pixel rate advantage — 20.03 GPixel/s vs 7.52 GPixel/s, a 166% lead. However, the R5 M255’s texture rate is slightly higher at 22.56 GTexel/s vs 20.03 GTexel/s, thanks to more TMUs. The R5 M255 also has a wider bus interface (PCIe 3.0 x8 vs PCIe 3.0 x16), though the P400’s x16 interface is more conventional for a discrete card.

Head-to-Head Benchmarks

The Geekbench OpenCL test is the R5 M255’s strongest showing. It scores 4650, beating the P400’s 4249 by 9.4%. This is the largest delta between the two cards in any benchmark. The R5 M255’s advantage comes from its 384 shading units and 721.9 GFLOPS FP32 throughput, which outperforms the P400’s 641.0 GFLOPS despite the latter’s higher clocks. In compute-heavy OpenCL workloads, the extra shaders win out over architectural efficiency.

The Geekbench Vulkan test flips the result. The P400 scores 5119, edging out the R5 M255’s 4925 by 3.8%. This is a smaller margin, but it is significant because Vulkan is a more modern API and the P400 supports Vulkan 1.4 versus the R5 M255’s 1.2.170. The P400’s higher pixel rate and GDDR5 memory help it render more efficiently, and its Pascal architecture is better optimized for Vulkan’s low-overhead model. The R5 M255’s lead in OpenCL is nearly 2.5 times larger than the P400’s Vulkan lead, but both wins are real.

Looking at the broader context, the R5 M255’s average benchmark score is 4788, placing it just 0.1% behind the NVIDIA GeForce RTX 3080 12 GB (4791) — a remarkable parity given the RTX 3080 is a much higher-end card. The P400’s average score is 4684, which is 0.6% ahead of the AMD Radeon RX 9060 XT 16 GB (4657) and the AMD Radeon R5 M320 (4657), and 0.9% behind the AMD Radeon R8 M445DX (4727). These rival comparisons show both cards are clustered tightly in the low-to-mid range, with differences of only a few percentage points separating them from several other GPUs.

FAQ

Q: Which GPU has a higher average benchmark score?

A: The AMD Radeon R5 M255 has an average benchmark score of 4788, while the NVIDIA Quadro P400 scores 4684. The R5 M255 leads by 104 points, or roughly 2.2%.

Q: Why does the AMD R5 M255 win in OpenCL but lose in Vulkan?

A: The R5 M255 has 384 shading units and 721.9 GFLOPS FP32, giving it a compute advantage that shows in OpenCL (4650 vs 4249, a 9.4% win). The P400’s Pascal architecture, higher clocks (1228 MHz base vs 925 MHz), and Vulkan 1.4 support allow it to win Vulkan (5119 vs 4925, a 3.8% win).

Q: What is the memory bandwidth difference between the two?

A: The R5 M255 has 32.00 GB/s bandwidth using 2 GB DDR3 on a 128-bit bus, while the P400 has 32.06 GB/s using 2 GB GDDR5 on a 64-bit bus. The P400 achieves slightly higher bandwidth despite half the bus width due to faster memory.

Q: Which GPU has a higher pixel rate?

A: The NVIDIA Quadro P400 has a pixel rate of 20.03 GPixel/s, which is more than 2.5 times the R5 M255’s 7.52 GPixel/s, thanks to its 16 ROPs versus the AMD’s 8 ROPs.

Q: How do these GPUs compare to recent cards in the database?

A: The R5 M255’s average score is 0.1% below the NVIDIA GeForce RTX 3080 12 GB (4791), while the P400 is 0.6% above the AMD Radeon RX 9060 XT 16 GB (4657) and 1.2% above the NVIDIA GeForce GTX 970M (4628).

Q: What are the TDP and power requirements?

A: The Quadro P400 has a TDP of 30 W, requires no power connectors, and has a suggested PSU of 200 W. The R5 M255 has no TDP listed in the data.

The Verdict

The data points to a clear but narrow split. For OpenCL compute tasks, the AMD Radeon R5 M255 is the better choice — its 9.4% lead over the P400 in Geekbench OpenCL is the largest performance delta between the two, and its 384 shading units deliver higher FP32 throughput (721.9 GFLOPS vs 641.0 GFLOPS). If your workload is OpenCL-based, the R5 M255 wins decisively.

For Vulkan-based applications, the NVIDIA Quadro P400 is the pick. Its 3.8% Vulkan lead, combined with Vulkan 1.4 support (versus 1.2.170 on the AMD), makes it more future-proof for modern APIs. The P400 also offers a dramatically higher pixel rate (20.03 GPixel/s vs 7.52 GPixel/s) and a lower TDP of 30 W, making it more power-efficient for sustained workloads. The P400’s single-slot design and lack of power connectors also make it easier to integrate into compact systems.

Users who prioritize raw compute in OpenCL should choose the AMD R5 M255. Users who need modern API support, higher pixel throughput, or lower power consumption should choose the NVIDIA Quadro P400. The 1-1 win count means there is no overall winner — only the right tool for the job.

Specification Differences

| Specification | AMD Radeon R5 M255 | NVIDIA Quadro P400 |

|----------------|---------------------|--------------------|

| Architecture | GCN 3.0 | Pascal |

| Process Node | 28 nm (TSMC) | 14 nm (Samsung) |

| Transistors | 1,550 million | 3,300 million |

| Die Size | 125 mm² | 132 mm² |

| Transistor Density | 12.4M / mm² | 25.0M / mm² |

| Base Clock | 925 MHz | 1228 MHz |

| Boost Clock | 940 MHz | 1252 MHz |

| Memory Type | DDR3 | GDDR5 |

| Memory Bus Width | 128 bit | 64 bit |

| Memory Effective Speed | 2 Gbps | 4 Gbps |

| Shading Units | 384 | 256 |

| TMUs | 24 | 16 |

| ROPs | 8 | 16 |

| Pixel Rate | 7.52 GPixel/s | 20.03 GPixel/s |

| Texture Rate | 22.56 GTexel/s | 20.03 GTexel/s |

| FP32 Performance | 721.9 GFLOPS | 641.0 GFLOPS |

| FP16 Performance | 721.9 GFLOPS (1:1) | 10.02 GFLOPS (1:64) |

| TDP | Not listed | 30 W |

| Slot Width | Not listed | Single-slot |

| Power Connectors | Not listed | None |

| Suggested PSU | Not listed | 200 W |

| Bus Interface | PCIe 3.0 x8 | PCIe 3.0 x16 |

| Display Outputs | Not listed | 3x mini-DisplayPort 1.4a |

| Vulkan Support | 1.2.170 | 1.4 |

| Release Date | 2014-10-11 | 2017-02-06 |