AMD Radeon 820M vs NVIDIA GeForce RTX 4090 D Comparison

The Verdict

The data presents a complete mismatch. The NVIDIA GeForce RTX 4090 D is a top-tier discrete graphics card, while the AMD Radeon 820M is an integrated processor graphics solution. The RTX 4090 D sits in the 98th percentile of all GPUs in the database, whereas the Radeon 820M sits in the 50th percentile. The RTX 4090 D records an average benchmark score of 178050 across its three tested workloads, while the Radeon 820M has no recorded benchmark scores at all.

Any user requiring high-end rendering, ray tracing, or compute workloads should choose the RTX 4090 D. The Radeon 820M is suited only for basic display output and light graphical tasks in a portable device, given its 15 W TDP and integrated design. The RTX 4090 D is end-of-life per the database, but it remains a production-status product for the Radeon 820M. The choice is dictated entirely by the workload: the RTX 4090 D for performance, the Radeon 820M for minimal power draw in an IGP form factor.

Architecture Differences

The two GPUs come from different manufacturers, process nodes, and architectural generations. The AMD Radeon 820M uses the RDNA 3.5 architecture, built on a 4 nm process at TSMC, and belongs to the Navi III IGP generation for Strix Point Mobile. Its chip is labeled Krackan Point 2. The NVIDIA GeForce RTX 4090 D uses the Ada Lovelace architecture, built on a 5 nm process at TSMC, and belongs to the GeForce 40 series with the AD102 chip.

The RTX 4090 D has a transistor count of 76,300 million and a die size of 609 mm², with a transistor density of 125.3M per mm². The Radeon 820M's transistor count and die size are unknown in the database. The RTX 4090 D uses 14,592 shading units, 456 texture mapping units, and 176 raster operation units. The Radeon 820M uses 128 shading units, 8 TMUs, and 4 ROPs. The RTX 4090 D includes 114 ray tracing cores and 456 tensor cores, while the Radeon 820M has 2 ray tracing cores and no tensor cores listed.

The memory subsystems are fundamentally different. The RTX 4090 D has 24 GB of GDDR6X memory on a 384-bit bus with 1.01 TB/s bandwidth. The Radeon 820M uses system shared memory with a system dependent bandwidth and bus width. The RTX 4090 D has a base clock of 2280 MHz and a boost clock of 2520 MHz, with memory clocked at 1313 MHz (21 Gbps effective). The Radeon 820M has a base clock of 400 MHz and a boost clock of 2800 MHz, but its memory clock is system shared.

Both GPUs support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The RTX 4090 D displays triple-slot width with a 1x 16-pin power connector and a suggested PSU of 800 W. The Radeon 820M is an IGP with no power connectors and no suggested PSU listed.

Head-to-Head Benchmarks

The database contains no head-to-head benchmark entries for these two GPUs. The Radeon 820M has zero recorded benchmarks and zero wins. The RTX 4090 D has three recorded benchmark scores, all in compute and graphics workloads.

In 3DMark Steel Nomad DX12, the RTX 4090 D scores 8587. In Geekbench OpenCL, it scores 278621. In Geekbench Vulkan, it scores 246941. The average benchmark score across these runs is 178050. The Radeon 820M has an average benchmark score of 0, with no individual test scores recorded in the database.

The nearest rivals to the RTX 4090 D provide context for its performance tier. The NVIDIA RTX PRO 5000 Blackwell has an average score of 182109, which is 2.2% higher than the RTX 4090 D. The NVIDIA A100 SXM4 80 GB scores 183725, 3.1% higher. The NVIDIA RTX 5000 Ada Generation scores 184664, 3.6% higher. The NVIDIA A100 SXM4 40 GB scores 187147, 4.9% higher. These deltas show the RTX 4090 D sits just below the top of the professional compute stack, but it is firmly within the highest performance tier.

The Radeon 820M has no nearest rivals listed, meaning the database has no comparable GPUs for its performance class. Its percentile rank of 50 places it in the middle of all GPUs, but this is based on no actual benchmark data, suggesting the rank is derived from its specifications rather than measured performance.

Specification Differences

The two GPUs differ in nearly every specification field. The Radeon 820M uses a 4 nm process, while the RTX 4090 D uses 5 nm. The RTX 4090 D has a known transistor count of 76,300 million and die size of 609 mm²; the Radeon 820M lists both 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 D has a base clock of 2280 MHz and a boost clock of 2520 MHz. The Radeon 820M boosts higher, but with far fewer execution units.

The shading unit counts are 128 for the Radeon 820M versus 14,592 for the RTX 4090 D. TMUs are 8 versus 456. ROPs are 4 versus 176. Ray tracing cores are 2 versus 114. Tensor cores are absent on the Radeon 820M, while the RTX 4090 D has 456.

Pixel rates are 11.20 GPixel/s for the Radeon 820M and 443.5 GPixel/s for the RTX 4090 D. Texture rates are 22.40 GTexel/s versus 1,149.1 GTexel/s. FP32 compute is 716.8 GFLOPS versus 73.54 TFLOPS. Both have FP16 at a 1:1 ratio with FP32.

Power consumption is 15 W for the Radeon 820M and 425 W for the RTX 4090 D. The RTX 4090 D requires a triple-slot cooler, a 1x 16-pin power connector, and an 800 W suggested PSU. The Radeon 820M is an IGP with no connectors.

Memory is system shared for the Radeon 820M, while the RTX 4090 D has 24 GB of GDDR6X on a 384-bit bus with 1.01 TB/s bandwidth. The RTX 4090 D has a bus interface of PCIe 4.0 x16, while the Radeon 820M uses PCIe 4.0 x8. Display outputs are portable device dependent for the Radeon 820M and 1x HDMI 2.1 plus 3x DisplayPort 1.4a for the RTX 4090 D.

The RTX 4090 D measures 304 mm in length, 137 mm in height, and 61 mm in width. It was released on 2023-12-27 with a launch MSRP of 1,599 USD. The Radeon 820M was released on 2025-02-28. The RTX 4090 D is end-of-life, while the Radeon 820M is active. The RTX 4090 D's predecessor is GeForce 30 and successor is GeForce 50. The Radeon 820M's predecessor is Navi II IGP.

FAQ

Q: Which GPU has the higher FP32 compute performance?

A: The RTX 4090 D delivers 73.54 TFLOPS of FP32 compute, while the Radeon 820M delivers 716.8 GFLOPS. The RTX 4090 D is over 100 times higher in raw floating-point throughput.

Q: What is the memory capacity of each GPU?

A: The RTX 4090 D has 24 GB of GDDR6X memory on a 384-bit bus with 1.01 TB/s bandwidth. The Radeon 820M uses system shared memory, with its size, type, and bandwidth all dependent on the host system.

Q: Which GPU has ray tracing support?

A: Both support DirectX 12 Ultimate, which includes ray tracing. The RTX 4090 D has 114 dedicated ray tracing cores, while the Radeon 820M has only 2 ray tracing cores.

Q: What are the power requirements?

A: The Radeon 820M has a TDP of 15 W and requires no power connectors. The RTX 4090 D has a TDP of 425 W, uses a triple-slot cooler, requires a 1x 16-pin power connector, and has a suggested PSU of 800 W.

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

A: The RTX 4090 D has an average benchmark score of 178050. The NVIDIA RTX PRO 5000 Blackwell is 2.2% higher, the A100 SXM4 80 GB is 3.1% higher, the RTX 5000 Ada Generation is 3.6% higher, and the A100 SXM4 40 GB is 4.9% higher.

Q: What is the production status of each GPU?

A: The Radeon 820M is listed as Active production. The RTX 4090 D is listed as End-of-life, with its successor being the GeForce 50 series.

Where Each One Wins

The RTX 4090 D wins in every performance category with recorded data. Its 73.54 TFLOPS FP32 performance, 1,149.1 GTexel/s texture rate, and 443.5 GPixel/s pixel rate place it in the top 2% of all GPUs. The 3DMark Steel Nomad score of 8587, Geekbench OpenCL score of 278621, and Geekbench Vulkan score of 246941 confirm its position. Its 114 ray tracing cores and 456 tensor cores make it suited for ray-traced rendering and AI-accelerated workloads. The 24 GB GDDR6X memory with 1.01 TB/s bandwidth supports large data sets and high-resolution textures.

The Radeon 820M wins in power efficiency and form factor. Its 15 W TDP is a fraction of the RTX 4090 D's 425 W. Its IGP design requires no power connectors, no dedicated cooler, and no additional card slot. The boost clock of 2800 MHz is higher than the RTX 4090 D's 2520 MHz, though with far fewer execution units. Its 2 ray tracing cores provide basic RT support in a portable device context. The system shared memory approach means it has no dedicated VRAM cost.

For desktop workstations, high-end gaming, professional rendering, or compute tasks, the RTX 4090 D is the clear choice. For thin-and-light portable devices where power draw is the primary constraint, the Radeon 820M provides basic graphics capability within a 15 W envelope. The database records no benchmark wins for the Radeon 820M, while the RTX 4090 D has three recorded scores, all in demanding workloads. The use case split is therefore unambiguous: performance versus portability.