AMD Radeon R5 M420 vs AMD Radeon Vega 3 Comparison

# Head-to-Head Benchmarks

The only directly comparable benchmark between the AMD Radeon Vega 3 and the AMD Radeon R5 M420 is Geekbench OpenCL, and the margin is razor-thin. The Vega 3 scores 3963, while the R5 M420 scores 3956. That amounts to a 0.2% delta in favor of the Vega 3 — effectively a statistical tie in raw compute throughput. The data shows a single win for the Vega 3 and zero for the R5 M420, but the practical performance difference is negligible for most workloads.

Looking at the broader benchmark landscape, the Vega 3 holds an average benchmark score of 4268 across three tests (Geekbench Metal, OpenCL, and Vulkan), placing it in the 25th percentile of all GPUs. Its nearest rivals include the NVIDIA GeForce GTX 460M at 4282 (-0.3%), the AMD FirePro W2100 at 4295 (-0.6%), and the NVIDIA Quadro K3000M at 4241 (+0.6%). The R5 M420, by contrast, has a single OpenCL score of 3956 and sits at the 23rd percentile, with rivals like the NVIDIA GeForce 830M at 3957 (0% delta), the NVIDIA GeForce GT 745M at 3953 (+0.1%), and the AMD Radeon HD 6850 X2 at 3977 (-0.5%).

What is striking here is how closely both GPUs track their respective competition. The Vega 3's OpenCL score of 3963 is within 1.5% of the NVIDIA GeForce RTX 4070 GDDR6's average score of 4335 — a result that underscores how synthetic compute benchmarks can flatten differences that matter in real rendering workloads. The R5 M420's single OpenCL result lands within 0.5% of the Quadro K2000's 3964 average.

The Vega 3's additional benchmark coverage reveals more about its character. Its Geekbench Vulkan score of 3961 nearly matches its OpenCL result, while its Metal score of 4880 stands significantly higher — a 23.1% improvement over its own OpenCL figure. That spread suggests the architecture responds well to Apple's Metal API, though the R5 M420 has no comparable data to measure against.

# Architecture Differences

The two GPUs come from different generations of AMD's Graphics Core Next architecture, and that distinction matters deeply. The Vega 3 uses GCN 5.0, built on a 12 nm process at GlobalFoundries, with the Picasso chip. The R5 M420 uses the original GCN 1.0 architecture, manufactured on a 28 nm process at TSMC, with the Jet chip. The process gap alone — 12 nm versus 28 nm — explains much of the efficiency and feature divergence.

Transistor counts tell a dramatic story. The Vega 3's Picasso die contains 4,940 million transistors across a 210 mm² die, yielding a transistor density of 23.5 million per square millimeter. The R5 M420's Jet die packs just 690 million transistors into 56 mm², for a density of 12.3 million per square millimeter. The Vega 3 has roughly 7.2 times the transistor count but only 3.75 times the die area, reflecting the denser 12 nm process.

Compute resources are where the R5 M420 actually leads on paper. The R5 M420 fields 320 shading units, 20 texture mapping units, and 8 ROPs, versus the Vega 3's 192 shading units, 12 TMUs, and 4 ROPs. That translates to a higher theoretical pixel rate of 6.800 GPixel/s and texture rate of 17.00 GTexel/s for the R5 M420, against 4.400 GPixel/s and 13.20 GTexel/s for the Vega 3. The R5 M420 also posts higher FP32 throughput at 544.0 GFLOPS, versus 422.4 GFLOPS for the Vega 3.

Clock speeds flip the story in the other direction. The R5 M420 runs at a base of 780 MHz with a boost of 850 MHz, while the Vega 3 starts at a lowly 300 MHz base but boosts to 1100 MHz. That 29.4% clock advantage at boost helps the Vega 3 close the gap in real-world workloads, despite fewer execution units. The Vega 3 also supports FP16 at 844.8 GFLOPS (2:1 ratio), a feature entirely absent from the R5 M420's specifications.

Memory configurations diverge completely. The R5 M420 carries 4 GB of dedicated DDR3 memory on a 64-bit bus, with 16.00 GB/s of bandwidth. The Vega 3 uses system-shared memory with no dedicated VRAM, making its bandwidth "System Dependent." The R5 M420's memory clock is listed at 1000 MHz (2 Gbps effective). The Vega 3's memory clock is simply "System Shared."

API support favors the Vega 3. It supports DirectX 12 (12_1), OpenGL 4.6, and Vulkan 1.3. The R5 M420 supports DirectX 12 but only at the (11_1) feature level, OpenGL 4.6, and Vulkan 1.2.170. The bus interface also differs: the Vega 3 is an IGP with no bus interface beyond the motherboard, while the R5 M420 connects via PCIe 3.0 x8.

# Where Each One Wins

The R5 M420 wins on raw compute specifications. It has 66.7% more shading units, 66.7% more TMUs, and double the ROPs of the Vega 3. Its FP32 throughput of 544.0 GFLOPS is 28.8% higher than the Vega 3's 422.4 GFLOPS. For workloads that scale with raw shader count — older DirectX 11 games, compute tasks that don't leverage newer instruction sets — the R5 M420 should hold an edge, even if the benchmark data doesn't show it decisively.

The Vega 3 wins on architectural modernity. GCN 5.0 brings features and optimizations that GCN 1.0 simply cannot access. The Vulkan 1.3 support versus 1.2.170 matters for newer titles. DirectX 12 (12_1) versus (11_1) means the Vega 3 can handle more advanced D3D12 feature levels. The FP16 support at 844.8 GFLOPS gives it a path to accelerated half-precision workloads that the R5 M420 lacks entirely.

The Vega 3 also wins on process efficiency. The 12 nm node at GlobalFoundries versus 28 nm at TSMC means substantially lower power draw per transistor. The Vega 3's TDP is listed at 15 W, while the R5 M420's TDP is not specified at all — but the older, larger process would inherently consume more power for comparable work. The Vega 3's 300 MHz base clock suggests aggressive power management when idle, ramping to 1100 MHz under load.

In terms of benchmark results, the Vega 3's OpenCL score of 3963 edges out the R5 M420's 3956 by 0.2%. That single point of comparison doesn't provide enough data to declare a clear winner in compute workloads. The Vega 3's Metal score of 4880, however, suggests it performs disproportionately well in Apple ecosystem applications, though the R5 M420 has no Metal benchmark to compare.

For users on a tight power budget, the Vega 3's 15 W TDP and integrated design make it the obvious choice. For users who need dedicated memory and consistent bandwidth regardless of system RAM, the R5 M420's 4 GB DDR3 on a 64-bit bus offers a more predictable experience. The R5 M420's PCIe 3.0 x8 interface also means it can be swapped between compatible systems, whereas the Vega 3 is permanently fused to its host processor.

# FAQ

Q: Which GPU is faster in OpenCL benchmarks?

A: The AMD Radeon Vega 3 scores 3963 in Geekbench OpenCL, while the AMD Radeon R5 M420 scores 3956. The Vega 3 wins by 0.2% — a margin well within benchmark noise.

Q: Does the R5 M420 have more shading units than the Vega 3?

A: Yes. The R5 M420 features 320 shading units, 20 TMUs, and 8 ROPs. The Vega 3 has 192 shading units, 12 TMUs, and 4 ROPs — roughly two-thirds as many in each category.

Q: What API versions does each GPU support?

A: The Vega 3 supports DirectX 12 (12_1), OpenGL 4.6, and Vulkan 1.3. The R5 M420 supports DirectX 12 (11_1), OpenGL 4.6, and Vulkan 1.2.170.

Q: How much memory does the R5 M420 have?

A: The R5 M420 has 4 GB of dedicated DDR3 memory on a 64-bit bus, with 16.00 GB/s bandwidth. The Vega 3 uses system-shared memory with bandwidth dependent on the host system.

Q: What process nodes are used for each chip?

A: The Vega 3's Picasso chip is built on a 12 nm process at GlobalFoundries, with 4,940 million transistors on a 210 mm² die. The R5 M420's Jet chip uses a 28 nm process at TSMC, with 690 million transistors on a 56 mm² die.

Q: Which GPU has a higher boost clock?

A: The Vega 3 boosts to 1100 MHz, compared to the R5 M420's 850 MHz boost. The Vega 3's base clock is lower at 300 MHz versus 780 MHz, but its boost ceiling is 29.4% higher.

# Specification Differences

| Specification | AMD Radeon Vega 3 | AMD Radeon R5 M420 |

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

| Architecture | GCN 5.0 | GCN 1.0 |

| Process Node | 12 nm | 28 nm |

| Foundry | GlobalFoundries | TSMC |

| Transistors | 4,940 million | 690 million |

| Die Size | 210 mm² | 56 mm² |

| Transistor Density | 23.5M / mm² | 12.3M / mm² |

| Base Clock | 300 MHz | 780 MHz |

| Boost Clock | 1100 MHz | 850 MHz |

| Memory Size | System Shared | 4 GB |

| Memory Type | System Shared | DDR3 |

| Memory Bus Width | System Shared | 64 bit |

| Memory Bandwidth | System Dependent | 16.00 GB/s |

| Memory Clock | System Shared | 1000 MHz (2 Gbps effective) |

| Shading Units | 192 | 320 |

| TMUs | 12 | 20 |

| ROPs | 4 | 8 |

| Pixel Rate | 4.400 GPixel/s | 6.800 GPixel/s |

| Texture Rate | 13.20 GTexel/s | 17.00 GTexel/s |

| FP32 | 422.4 GFLOPS | 544.0 GFLOPS |

| FP16 | 844.8 GFLOPS (2:1) | None |

| TDP | 15 W | Not specified |

| Bus Interface | IGP | PCIe 3.0 x8 |

| DirectX | 12 (12_1) | 12 (11_1) |

| Vulkan | 1.3 | 1.2.170 |

| Display Outputs | Motherboard Dependent | Portable Device Dependent |

| Release Date | 2019-11-19 | 2016-05-14 |

| Predecessor | GCN 3.0 IGP | Solar System |

| Successor | Vega II IGP | Polaris Mobile |

| Avg Benchmark Score | 4268 | 3956 |

| Percentile | 25 | 23 |