AMD Radeon R6 M255DX vs NVIDIA Quadro P400 Comparison

# AMD Radeon R6 M255DX vs NVIDIA Quadro P400

The AMD Radeon R6 M255DX and NVIDIA Quadro P400 occupy nearly the same performance tier, yet they approach it from completely different directions. The R6 M255DX is an integrated graphics solution from 2014, built on GCN 1.0 and sharing system memory, while the Quadro P400 is a 2017 discrete workstation card with dedicated GDDR5. In the single head-to-head benchmark available — Geekbench Vulkan — the Quadro P400 scores 5119 against the R6 M255DX’s 4867, a 4.9% margin. That is a narrow victory, one that raises questions about whether the older integrated part can genuinely compete with a dedicated professional GPU, or whether the benchmark’s scope hides deeper architectural gaps. The data suggests the Quadro P400 wins the only direct comparison, but the R6 M255DX’s rival list shows it trading blows with much newer discrete parts, hinting that raw compute is not the whole story.

The Verdict

The data points to a clear, if modest, recommendation: the NVIDIA Quadro P400 is the stronger pick for anyone who needs a dedicated, self-contained GPU with consistent memory bandwidth. Its Geekbench Vulkan score of 5119 beats the AMD Radeon R6 M255DX’s 4867 by 4.9%, and it carries a 27th percentile ranking versus the AMD part’s 28th — essentially identical standing among all GPUs, but the NVIDIA card does so with a discrete 2 GB GDDR5 frame buffer and a 64-bit bus delivering 32.06 GB/s. The R6 M255DX, by contrast, relies on “System Shared” memory with bandwidth described only as “System Dependent,” which means real-world performance could swing wildly based on the host laptop’s RAM configuration. For users building or upgrading a small workstation, the Quadro P400’s single-slot design, 150 mm length, and 30 W TDP with no power connectors make it a straightforward drop-in card. The AMD part is an IGP, permanently fused to a portable device, so it cannot be purchased or installed separately. If the choice is between a laptop with the R6 M255DX and a desktop with the Quadro P400, the data favors the NVIDIA solution for its superior raw score, dedicated memory, and professional feature set. However, the R6 M255DX is not embarrassing: its 4867 Vulkan score is only 0.5% behind the GeForce 940MX and 0.2% ahead of the GTX 560M, showing that an old integrated chip can still match entry-level discrete GPUs from its era. There is no scenario in the facts where the AMD part wins a benchmark, so the verdict leans NVIDIA, but the margin is thin enough that a user with an existing R6 M255DX system might not feel compelled to upgrade solely on Vulkan performance.

Architecture Differences

The two GPUs come from different manufacturing generations and design philosophies. The AMD Radeon R6 M255DX uses the “Jet” chip on a 28 nm TSMC process, packing 690 million transistors into a 56 mm² die, yielding a transistor density of 12.3 million per square millimeter. Its architecture is GCN 1.0, a design that debuted in 2012 and emphasizes compute throughput over memory efficiency. The NVIDIA Quadro P400 uses the GP107 chip on a 14 nm Samsung process, with 3,300 million transistors on a 132 mm² die — a density of 25.0 million per square millimeter, more than double the AMD part. The Quadro runs on the Pascal architecture, which introduced significant improvements in clock scaling and memory compression. The R6 M255DX features 320 shading units, 20 texture mapping units, and 8 render output units, while the Quadro P400 has 256 shading units, 16 TMUs, and 16 ROPs. That means the AMD part has 25% more shaders and 25% more TMUs, but half the ROPs. Clock speeds tell a different story: the R6 M255DX runs at 780 MHz base and 855 MHz boost, while the Quadro P400 runs at 1228 MHz base and 1252 MHz boost — roughly 44% higher base clocks. Memory is the starkest difference. The R6 M255DX has no dedicated memory; it uses system RAM with a bus width and type both listed as “System Shared,” making bandwidth “System Dependent.” The Quadro P400 has 2 GB of GDDR5 on a 64-bit bus, delivering 32.06 GB/s at an effective 4 Gbps speed. Pixel and texture rates favor the NVIDIA card: 20.03 GPixel/s and 20.03 GTexel/s versus the AMD’s 6.840 GPixel/s and 17.10 GTexel/s. The Quadro’s pixel rate is nearly three times higher, a direct result of its double ROP count and higher clocks. FP32 compute goes to the Quadro at 641.0 GFLOPS versus 547.2 GFLOPS, a 17% lead. The Quadro also lists FP16 at 10.02 GFLOPS (1:64 ratio), while the AMD part has no FP16 data. Manufacturing differences are significant: the R6 M255DX is built on a mature 28 nm node, while the Quadro P400 uses the newer 14 nm process, which explains the Quadro’s lower 30 W TDP despite higher clocks and dedicated memory. The R6 M255DX’s TDP is not listed, but as an IGP it shares thermal and power budgets with the host CPU. API support also diverges: the R6 M255DX supports DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170, while the Quadro P400 supports DirectX 12 (12_1), OpenGL 4.6, and Vulkan 1.4. The Quadro’s newer Vulkan version and full DirectX 12_1 feature set give it an edge in modern titles and compute workloads.

FAQ

Q: Which GPU has the higher Geekbench Vulkan score?

A: The NVIDIA Quadro P400 scores 5119, which is 4.9% higher than the AMD Radeon R6 M255DX’s 4867.

Q: Does the AMD Radeon R6 M255DX have its own dedicated memory?

A: No. The R6 M255DX uses “System Shared” memory for size, type, and bus width, with bandwidth listed as “System Dependent,” meaning it relies entirely on the host system’s RAM.

Q: What is the transistor count difference between the two chips?

A: The AMD Radeon R6 M255DX’s Jet chip contains 690 million transistors, while the NVIDIA Quadro P400’s GP107 chip contains 3,300 million transistors — nearly five times as many.

Q: Which GPU has a higher pixel fill rate?

A: The NVIDIA Quadro P400 achieves 20.03 GPixel/s, which is roughly 2.9 times the AMD Radeon R6 M255DX’s 6.840 GPixel/s.

Q: Are both GPUs still in production?

A: No. The AMD Radeon R6 M255DX is listed as end-of-life with a release date of 2014-01-06, and the NVIDIA Quadro P400 is also end-of-life with a release date of 2017-02-06.

Q: How do the two GPUs compare in their nearest rival matchups?

A: The R6 M255DX’s closest rival is the NVIDIA GeForce GTS 450 at 4893 (0.5% higher), while the Quadro P400’s closest rival is the AMD Radeon R8 M445DX at 4727 (0.9% higher).

Specification Differences

The two GPUs differ across nearly every specification category. The AMD Radeon R6 M255DX uses the Jet chip on GCN 1.0 architecture, while the NVIDIA Quadro P400 uses GP107 on Pascal. The manufacturing process is 28 nm (TSMC) for AMD versus 14 nm (Samsung) for NVIDIA. Transistor counts are 690 million versus 3,300 million, and die sizes are 56 mm² versus 132 mm² — the NVIDIA chip is larger in both raw dimensions and transistor count, but the density is 12.3M/mm² for AMD versus 25.0M/mm² for NVIDIA. Clock speeds: the R6 M255DX runs at 780 MHz base and 855 MHz boost, while the Quadro P400 runs at 1228 MHz base and 1252 MHz boost. Memory is entirely different: the AMD part has system-shared memory with no dedicated size, type, or bus width, while the NVIDIA card has 2 GB GDDR5 on a 64-bit bus at 32.06 GB/s. Shading units are 320 for AMD versus 256 for NVIDIA; TMUs are 20 versus 16; ROPs are 8 versus 16. Pixel rates are 6.840 GPixel/s versus 20.03 GPixel/s; texture rates are 17.10 GTexel/s versus 20.03 GTexel/s; FP32 is 547.2 GFLOPS versus 641.0 GFLOPS. The Quadro P400 has a 30 W TDP, while the R6 M255DX has no listed TDP. The AMD part is an IGP with no slot width, power connectors, or suggested PSU, while the Quadro P400 is a single-slot card measuring 150 mm by 69 mm, with no power connectors and a suggested 200 W PSU. Bus interfaces are IGP versus PCIe 3.0 x16. Display outputs are “Portable Device Dependent” for AMD versus 3x mini-DisplayPort 1.4a for NVIDIA. API support differs: DirectX 12 (11_1) versus 12 (12_1), same OpenGL 4.6, and Vulkan 1.2.170 versus 1.4. Release dates are 2014-01-06 versus 2017-02-06. The Quadro P400 has a predecessor (Quadro Maxwell) and successor (Quadro Volta), while the AMD part has neither listed.

Head-to-Head Benchmarks

The only direct benchmark comparison available is Geekbench Vulkan, and it shows the NVIDIA Quadro P400 winning decisively but not overwhelmingly. The Quadro P400 scores 5119, while the AMD Radeon R6 M255DX scores 4867, a delta of 4.9% in favor of NVIDIA. That margin is small enough to be within run-to-run variance for many workloads, but the underlying specifications suggest why the NVIDIA card pulls ahead. The Quadro P400’s FP32 compute is 641.0 GFLOPS versus 547.2 GFLOPS for the AMD part — a 17% advantage — and its pixel rate of 20.03 GPixel/s is nearly triple the R6 M255DX’s 6.840 GPixel/s. Memory bandwidth is the biggest qualitative gap: the Quadro has 32.06 GB/s of dedicated GDDR5 bandwidth, while the R6 M255DX’s bandwidth is “System Dependent,” meaning it shares the same memory bus as the CPU and other system components. In a benchmark like Vulkan, which often stresses both compute and memory access, the Quadro’s dedicated memory and higher clocks likely compensate for its lower shader count (256 versus 320). The texture rate is closer: 20.03 GTexel/s for NVIDIA versus 17.10 GTexel/s for AMD, a 17% lead for the Quadro. The R6 M255DX’s only real advantage is raw shader count and TMU count, but those are outpaced by the Quadro’s clock speed advantage. The data also shows the R6 M255DX sits at the 28th percentile among all GPUs, while the Quadro P400 sits at the 27th — a negligible difference in overall standing. When looking at nearest rivals, the R6 M255DX’s 4867 score is within 0.7% of the GeForce RTX 5060 Ti 8 GB (4901), which is remarkable for a 2014 integrated chip, but that rival score is an average, not a direct head-to-head. The Quadro P400’s 5119 Vulkan score is its only listed benchmark, and it also has an OpenCL score of 4249, which the AMD part lacks entirely.

Where Each One Wins

The NVIDIA Quadro P400 wins in every measurable category where a direct comparison exists. It has the higher Geekbench Vulkan score (5119 versus 4867), higher FP32 compute (641.0 GFLOPS versus 547.2 GFLOPS), higher pixel rate (20.03 GPixel/s versus 6.840 GPixel/s), higher texture rate (20.03 GTexel/s versus 17.10 GTexel/s), and higher clocks (1228 MHz base versus 780 MHz). It also has dedicated 2 GB GDDR5 memory with a fixed 32.06 GB/s bandwidth, whereas the R6 M255DX depends on shared system memory with no guaranteed bandwidth. For professional use cases like CAD, 3D modeling, or multi-display setups, the Quadro P400’s 3x mini-DisplayPort 1.4a outputs and single-slot form factor make it a practical choice for a small workstation. Its 30 W TDP and lack of power connectors mean it can run in almost any desktop with a PCIe 3.0 x16 slot and a 200 W PSU. The AMD Radeon R6 M255DX, by contrast, wins in the context of portability — it is an IGP, meaning it adds no extra cost or power draw to a laptop, and its performance is sufficient to match or beat several discrete entry-level GPUs from its era. Its nearest rival comparisons show it trailing the GeForce GTS 450 by only 0.5% and the GTX 560M by 0.2%, while leading the GeForce 940MX by 0.5%. That suggests the R6 M255DX is a capable integrated solution for older games and light creative work, but it cannot match the Quadro P400’s dedicated memory bandwidth or modern feature set. The Quadro P400’s Vulkan 1.4 support versus the R6 M255DX’s Vulkan 1.2.170 also points to better long-term compatibility with newer software. In short, the Quadro P400 wins on raw performance, memory, and professional features, while the R6 M255DX wins only by being an integrated part with no additional hardware requirements — a trade-off that favors the NVIDIA card in any scenario where a discrete GPU is an option.