AMD Radeon 820M vs NVIDIA GeForce RTX 4090 Mobile Comparison

Head-to-Head Benchmarks

The database contains no overlapping benchmark scores for the AMD Radeon 820M and the NVIDIA GeForce RTX 4090 Mobile. The Radeon 820M has no recorded benchmark entries, while the RTX 4090 Mobile has nine recorded scores. The comparison therefore relies on the RTX 4090 Mobile's measured performance and the architectural specifications of both parts.

The RTX 4090 Mobile delivers an average benchmark score of 43,667 across its recorded tests. That figure places it at the 84th percentile of all GPUs in the database. Its nearest rivals in the aggregate ranking are the NVIDIA RTX A6000 at 44,075 (0.9% faster), the NVIDIA Quadro M6000 at 43,301 (0.8% slower), the NVIDIA GeForce RTX 5050 Mobile at 43,268 (0.9% slower), and the NVIDIA Quadro M6000 24 GB at 43,262 (0.9% slower). The spread among these five GPUs is remarkably tight, less than 2% from top to bottom.

Looking at individual tests, the RTX 4090 Mobile shows its strongest result in Geekbench OpenCL, scoring 180,831. Its Geekbench Vulkan score is 170,774, which is 5.9% lower than the OpenCL result. In Passmark's suite, the GPU records a G3D score of 27,212 and a compute score of 12,347. The legacy DirectX tests show scores of 310 for DirectX 9, 262 for DirectX 11, 173 for DirectX 10, and 107 for DirectX 12. The 2D test yields 984 points.

The Radeon 820M, by contrast, has zero recorded benchmarks and an average score of 0. Its percentile ranking sits at 50, which reflects its position relative to all GPUs in the database. With no measured data, the database cannot establish any comparative performance delta between the two parts. The Radeon 820M's theoretical peak FP32 throughput is 716.8 GFLOPS, while the RTX 4090 Mobile's FP32 rating is 32.98 TFLOPS. That is a 46x difference in raw shader output. The texture rate likewise differs by a wide margin: 22.40 GTexel/s against 515.3 GTexel/s, a 23x gap. Pixel throughput shows 11.20 GPixel/s versus 189.8 GPixel/s, a 17x difference.

In the absence of head-to-head benchmarks, the recorded data indicates that the RTX 4090 Mobile occupies a performance tier that the Radeon 820M does not approach. The RTX 4090 Mobile's 84th percentile placement places it among the higher-performing mobile GPUs in the database. The Radeon 820M's 50th percentile, with no supporting scores, reflects a mid-pack default ranking rather than a measured result.

The Verdict

The data separates these two GPUs into entirely different categories. The NVIDIA GeForce RTX 4090 Mobile is a high-end discrete-class part with a measured average score of 43,667 and a 84th percentile ranking. The AMD Radeon 820M is an integrated graphics processor with no benchmark records in the database.

Users requiring the performance level indicated by the RTX 4090 Mobile's scores, such as the 180,831 Geekbench OpenCL result or the 27,212 Passmark G3D score, should select that part. The RTX 4090 Mobile's nearest rivals in the database, including the NVIDIA RTX A6000 and Quadro M6000, all cluster within 0.9% of its average score, confirming that it operates at the top tier of recorded mobile GPUs.

Users constrained to an integrated solution would choose the Radeon 820M, but the database provides no measured evidence of its performance. Its 128 shading units, 8 TMUs, and 4 ROPs, along with a 15 W TDP, indicate a fundamentally different performance envelope than the RTX 4090 Mobile's 9,728 shading units, 304 TMUs, 112 ROPs, and 120 W TDP.

The RTX 4090 Mobile also carries architectural advantages beyond raw throughput. It includes 76 ray tracing cores and 304 tensor cores, while the Radeon 820M has 2 ray tracing cores and no tensor cores. For workloads that use these features, the RTX 4090 Mobile is the only viable option between the two. The RTX 4090 Mobile's 16 GB of dedicated GDDR6 memory with 576.0 GB/s bandwidth also contrasts sharply with the Radeon 820M's system-shared memory, whose bandwidth is system dependent.

FAQ

Q: Which GPU has a higher average benchmark score?

A: The NVIDIA GeForce RTX 4090 Mobile has an average benchmark score of 43,667. The AMD Radeon 820M has an average score of 0, with no recorded benchmarks.

Q: What is the RTX 4090 Mobile's best single benchmark result?

A: Its highest recorded score is 180,831 in Geekbench OpenCL. Its Geekbench Vulkan score is 170,774.

Q: How does the RTX 4090 Mobile compare to its nearest rivals?

A: The NVIDIA RTX A6000 is 0.9% faster, the Quadro M6000 is 0.8% slower, the GeForce RTX 5050 Mobile is 0.9% slower, and the Quadro M6000 24 GB is 0.9% slower.

Q: Does the Radeon 820M support ray tracing?

A: Yes, it has 2 ray tracing cores. The RTX 4090 Mobile has 76 ray tracing cores.

Q: What memory configurations do the two GPUs use?

A: The RTX 4090 Mobile uses 16 GB of GDDR6 memory on a 256-bit bus with 576.0 GB/s bandwidth. The Radeon 820M uses system-shared memory with system-dependent bandwidth.

Q: What are the TDP ratings?

A: The Radeon 820M has a TDP of 15 W. The RTX 4090 Mobile has a TDP of 120 W.

Specification Differences

The two GPUs differ in nearly every measured specification. The Radeon 820M uses a 4 nm process node, while the RTX 4090 Mobile uses 5 nm. The RTX 4090 Mobile has 45,900 million transistors on a 379 mm² die, giving a transistor density of 121.1M per mm². The Radeon 820M's transistor count and die size are listed as unknown.

Clock speeds differ substantially. The Radeon 820M has a base clock of 400 MHz and a boost clock of 2800 MHz. The RTX 4090 Mobile has a base clock of 1335 MHz and a boost clock of 1695 MHz. The RTX 4090 Mobile's memory clock is 2250 MHz (18 Gbps effective), while the Radeon 820M's memory clock is system shared.

The RTX 4090 Mobile uses a PCIe 4.0 x16 interface, while the Radeon 820M uses PCIe 4.0 x8. Both have no power connectors and an IGP slot width. Both are portable-device dependent for display outputs. The RTX 4090 Mobile was released on 2023-01-02, while the Radeon 820M was released on 2025-02-28.

The RTX 4090 Mobile has a predecessor (GeForce 30 Mobile) and a successor (GeForce 50 Mobile). The Radeon 820M has a predecessor (Navi II IGP) and no successor. The Radeon 820M belongs to the Navi III IGP generation with a Krackan Point 2 chip, while the RTX 4090 Mobile uses the AD103 chip in the GeForce 40 Mobile generation.

Architecture Differences

The Radeon 820M uses AMD's RDNA 3.5 architecture, fabricated on TSMC's 4 nm process. The RTX 4090 Mobile uses NVIDIA's Ada Lovelace architecture, fabricated on TSMC's 5 nm process. Both support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

The core configurations diverge dramatically. The Radeon 820M has 128 shading units, 8 texture mapping units, and 4 render output units. The RTX 4090 Mobile has 9,728 shading units, 304 TMUs, and 112 ROPs. That means the RTX 4090 Mobile has 76x more shaders, 38x more TMUs, and 28x more ROPs.

Ray tracing hardware differs by an order of magnitude. The Radeon 820M has 2 ray tracing cores. The RTX 4090 Mobile has 76 ray tracing cores. Tensor cores exist only on the RTX 4090 Mobile, which has 304 of them. The Radeon 820M has no tensor cores.

The FP16 and FP32 throughput ratios are identical at 1:1 for both GPUs, but the magnitudes differ. The Radeon 820M delivers 716.8 GFLOPS in both FP16 and FP32. The RTX 4090 Mobile delivers 32.98 TFLOPS in both precision formats. The RTX 4090 Mobile's texture rate is 515.3 GTexel/s versus 22.40 GTexel/s for the Radeon 820M. Pixel rates are 189.8 GPixel/s and 11.20 GPixel/s, respectively.

Memory architecture also differs fundamentally. The Radeon 820M relies on system-shared memory with no dedicated VRAM, while the RTX 4090 Mobile has 16 GB of GDDR6 on a 256-bit bus delivering 576.0 GB/s. The Radeon 820M's bandwidth is system dependent, meaning it varies with the host platform's memory configuration. The RTX 4090 Mobile's memory clock is fixed at 2250 MHz (18 Gbps effective).

The power envelopes reflect the performance gap. The Radeon 820M is rated at 15 W TDP, while the RTX 4090 Mobile is rated at 120 W TDP. Both are classified as IGP slot width with no power connectors. The Radeon 820M's production status is Active, as is the RTX 4090 Mobile's. Both GPUs are portable-device dependent for display outputs, meaning their video output capabilities depend on the host laptop or handheld device.