AMD Radeon 840M vs AMD Radeon RX 7800M Comparison
AMD Radeon 840M
Radeon RX 7800M
PERFORMANCE BENCHMARKS
Analysis: AMD Radeon 840M vs AMD Radeon RX 7800M
FAQ
Q: What are the core architectural identities of the AMD Radeon 840M and the AMD Radeon RX 7800M?
A: The Radeon 840M is an integrated graphics processor built on the Krackan Point chip using RDNA 3.5 architecture on a 4 nm TSMC process. The Radeon RX 7800M is a discrete mobile GPU based on the Navi 32 chip with RDNA 3.0 architecture on a 5 nm TSMC process.
Q: How do the memory subsystems compare between these two GPUs?
A: The Radeon 840M uses system shared memory with bandwidth described as system dependent. The Radeon RX 7800M has 12 GB of dedicated GDDR6 memory on a 192-bit bus, delivering 432.0 GB/s of bandwidth.
Q: Which GPU has a higher boost clock?
A: The Radeon 840M has a higher boost clock at 2900 MHz, while the Radeon RX 7800M boosts to 2335 MHz. However, the RX 7800M has a much higher base clock at 1295 MHz compared to 400 MHz for the 840M.
Q: What is the performance percentile ranking for each GPU in the database?
A: The Radeon 840M sits at the 50th percentile among all GPUs. The Radeon RX 7800M ranks at the 73rd percentile, placing it well above the median.
Q: What are the thermal design power (TDP) figures for both parts?
A: The Radeon 840M has a TDP of 15 W, reflecting its integrated nature. The Radeon RX 7800M carries a TDP of 180 W, consistent with a high-performance discrete mobile GPU.
Q: Which GPU offers more shading units and ray tracing cores?
A: The Radeon RX 7800M provides 3840 shading units and 60 ray tracing cores. The Radeon 840M provides 256 shading units and 4 ray tracing cores.
Architecture Differences
The two GPUs represent different design philosophies within AMD's mobile lineup. The Radeon 840M uses the newer RDNA 3.5 architecture, fabricated on a 4 nm TSMC process, and is integrated into the Krackan Point chip. This integration means it shares system memory and relies on the host platform for bandwidth, with a bus interface of PCIe 4.0 x8.
The Radeon RX 7800M uses RDNA 3.0 architecture on a 5 nm TSMC process, built around the Navi 32 chip with 28,100 million transistors on a 346 mm² die. It connects via PCIe 4.0 x16 and features a significantly larger execution footprint. The transistor density for the RX 7800M is recorded at 81.2M per mm².
Execution resources differ by an order of magnitude. The 840M contains 256 shading units, 16 texture mapping units, and 8 raster operation units. The RX 7800M contains 3840 shading units, 240 TMUs, and 96 ROPs. Ray tracing hardware follows the same pattern: 4 RT cores for the 840M versus 60 RT cores for the RX 7800M.
The memory architecture is fundamentally different. The 840M uses system shared memory with no dedicated VRAM, making its bandwidth dependent on the host system. The RX 7800M uses 12 GB of GDDR6 on a 192-bit bus, providing 432.0 GB/s of dedicated bandwidth. This distinction drives most of the performance gap in memory-intensive workloads.
Both GPUs support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The 840M's FP32 compute is rated at 1,484.8 GFLOPS, while the RX 7800M reaches 35.87 TFLOPS. Both support FP16 at a 1:1 ratio with FP32. The 840M has no listed predecessors or successors in its generation, while the RX 7800M lists Polarise Mobile as its predecessor.
Where Each One Wins
The Radeon 840M wins in power efficiency and integration. Its 15 W TDP makes it suitable for thin-and-light portable devices where thermal headroom is minimal. The 400 MHz base clock and 2900 MHz boost clock allow it to scale dynamically, and its IGP form factor requires no power connectors. The database places it at the 50th percentile, indicating median performance among all GPUs, which is respectable for an integrated solution.
The Radeon RX 7800M wins decisively in raw performance. It achieves the 73rd percentile in the database, a substantial jump over the 840M. Its nearest rivals include the AMD Radeon Pro Vega 20 (0.2% faster), AMD Radeon Pro W5500X (0.3% faster), NVIDIA GeForce GTX 980 Ti (0.5% faster), and AMD FirePro S7150 (0.8% faster). This clustering suggests the RX 7800M sits at a performance tier comparable to high-end desktop GPUs from previous generations.
The RX 7800M's 12 GB of dedicated GDDR6 memory with 432.0 GB/s bandwidth makes it the clear choice for texture-heavy workloads, high-resolution rendering, and compute tasks that require large working sets. The 840M, with system shared memory, must contend with bandwidth limitations imposed by the host system's memory controller.
The RX 7800M also delivers far higher fill rates: 224.2 GPixel/s versus 23.20 GPixel/s for the 840M, and 560.4 GTexel/s versus 46.40 GTexel/s. These numbers indicate that the RX 7800M is substantially better suited for rasterization-heavy workloads.
Specification Differences
The two GPUs differ across nearly every measurable specification. The 840M uses a 4 nm process node, while the RX 7800M uses 5 nm. The 840M's transistor count and die size are unknown in the database, while the RX 7800M has 28,100 million transistors on a 346 mm² die.
Clock behavior diverges significantly. The 840M has a base clock of 400 MHz and a boost clock of 2900 MHz. The RX 7800M has a base clock of 1295 MHz, a game clock of 2145 MHz, and a boost clock of 2335 MHz. The 840M boosts higher, but the RX 7800M maintains much higher sustained clocks.
Memory configurations are entirely different: the 840M uses system shared memory with no dedicated VRAM, while the RX 7800M has 12 GB of GDDR6 at 2250 MHz (18 Gbps effective) on a 192-bit bus. Bandwidth is system dependent for the 840M versus a fixed 432.0 GB/s for the RX 7800M.
Compute resources differ by a factor of 15 in shading units (256 versus 3840), 15 in TMUs (16 versus 240), and 12 in ROPs (8 versus 96). RT cores differ by a factor of 15 (4 versus 60). FP32 throughput is 1,484.8 GFLOPS for the 840M versus 35.87 TFLOPS for the RX 7800M.
TDP is 15 W for the 840M versus 180 W for the RX 7800M. Both are listed as IGP slot width with no power connectors. The bus interface is PCIe 4.0 x8 for the 840M and PCIe 4.0 x16 for the RX 7800M. Both have portable device dependent display outputs. The 840M released on 2025-02-28, while the RX 7800M released earlier on 2024-09-10.
Head-to-Head Benchmarks
The database does not include direct head-to-head benchmark results between these two GPUs. However, the Radeon RX 7800M has a substantial set of recorded benchmark scores that establish its performance tier. Its average benchmark score is 27,883, with a percentile rank of 73.
The RX 7800M's strongest recorded result is in Geekbench Vulkan with a score of 126,668, followed by Geekbench OpenCL at 120,778. These compute-oriented tests show the GPU's raw throughput capabilities. In 3DMark Steel Nomad DX12, it scores 2,994, which reflects modern gaming workload performance.
PassMark results for the RX 7800M show a G3D score of 17,613 and a GPU compute score of 9,342. DirectX 11 performance is recorded at 176, DirectX 9 at 174, DirectX 10 at 99, and DirectX 12 at 89. The G2D score is 892.
The closest rivals to the RX 7800M, based on average scores, are the AMD Radeon Pro Vega 20 at 27,839 (0.2% faster), AMD Radeon Pro W5500X at 27,973 (0.3% slower), NVIDIA GeForce GTX 980 Ti at 28,020 (0.5% slower), and AMD FirePro S7150 at 28,117 (0.8% slower). This tight clustering indicates the RX 7800M performs within approximately 1% of these established desktop and workstation GPUs.
The Radeon 840M has no recorded benchmark scores in the database and no nearest rivals listed. Its percentile rank of 50 places it at the median of all GPUs, but without individual test results, the data cannot quantify its performance in specific workloads. The absence of benchmark entries for the 840M means the database currently only supports performance conclusions for the RX 7800M. Based on the available data, the RX 7800M delivers a large performance advantage over the 840M, consistent with its 15x advantage in shading units, 15x advantage in TMUs, and 12x advantage in ROPs. The 840M remains a capable integrated solution for power-constrained devices, while the RX 7800M occupies a performance tier near the top of the mobile GPU range.