AMD Radeon 840M vs AMD Radeon RX 7800 XT Comparison

The Verdict

The AMD Radeon 840M and AMD Radeon RX 7800 XT occupy entirely different segments of the GPU market, and the recorded data reflects this clearly. The RX 7800 XT is a dedicated add-in board with a 263 W TDP, 16 GB of GDDR6 memory on a 256-bit bus, and 3840 shading units. The 840M is an integrated graphics processor with a 15 W TDP, system-shared memory, and 256 shading units. Their respective percentile rankings against all GPUs in the database are nearly identical at 51 and 50, but this is a misleading surface-level similarity. The RX 7800 XT has a substantial benchmark history with an average score of 11,627, while the 840M has no recorded benchmark scores at all, meaning its percentile is based on specification analysis rather than measured results.

The RX 7800 XT is the clear choice for any workload requiring sustained high-resolution rendering, ray tracing, or compute-heavy tasks. Its 60 RT cores, 96 ROPs, and 37.32 TFLOPS of FP32 performance place it in a different performance class entirely. The 840M, by contrast, is suited only for basic display output and light graphical tasks on a portable device. The data shows no head-to-head benchmark wins for either part, as no direct comparison tests exist in the database. Based on the specification differences and the RX 7800 XT's measured benchmark scores, the discrete card outperforms the integrated solution by an order of magnitude in nearly every measurable category.

FAQ

Q: Which GPU has a higher boost clock?

A: The AMD Radeon 840M has a boost clock of 2900 MHz, which is higher than the RX 7800 XT's boost clock of 2430 MHz. However, the RX 7800 XT compensates with far more shading units and a much higher base clock of 1295 MHz versus 400 MHz.

Q: How much memory bandwidth does each GPU provide?

A: The RX 7800 XT provides 624.1 GB/s of bandwidth from its 16 GB GDDR6 memory on a 256-bit bus. The 840M uses system-shared memory with bandwidth described as "System Dependent," meaning it varies based on the host system's memory configuration.

Q: What is the difference in FP32 floating-point performance?

A: The RX 7800 XT delivers 37.32 TFLOPS of FP32 performance, while the 840M delivers 1,484.8 GFLOPS (approximately 1.48 TFLOPS). This makes the RX 7800 XT roughly 25 times faster in raw FP32 throughput.

Q: Which GPU supports ray tracing?

A: Both GPUs support ray tracing. The 840M has 4 RT cores, while the RX 7800 XT has 60 RT cores. The RX 7800 XT's ray tracing hardware is significantly more robust, which is expected given its discrete design and higher power envelope.

Q: What are the power requirements for each GPU?

A: The 840M has a TDP of 15 W and requires no power connectors, making it suitable for portable devices. The RX 7800 XT has a TDP of 263 W, requires two 8-pin power connectors, and AMD suggests a 600 W power supply unit.

Q: When was each GPU released?

A: The RX 7800 XT was released on September 5, 2023, with a launch MSRP of 499 USD. The 840M was released on February 28, 2025, and has no recorded launch MSRP.

Architecture Differences

The two GPUs come from different architectural generations within AMD's RDNA family. The 840M uses RDNA 3.5 architecture on a 4 nm TSMC process node, while the RX 7800 XT uses RDNA 3.0 on a 5 nm TSMC node. This generational difference means the 840M benefits from a newer architecture iteration, but the RX 7800 XT's massive scale advantage overwhelms any per-architecture efficiency gains.

The RX 7800 XT is built on the Navi 32 chip with 28,100 million transistors on a 346 mm² die, yielding a transistor density of 81.2M per mm². The 840M uses the Krackan Point chip, but its transistor count and die size are listed as unknown in the database. The RX 7800 XT belongs to the Radeon RX 7000 series and the Navi III (RX 7000) generation, with the codename "Wheat Nas." The 840M belongs to the Navi III IGP (Strix Point Mobile) generation and carries no codename.

The 840M is classified as an IGP (integrated graphics processor) with a PCIe 4.0 x8 bus interface, while the RX 7800 XT is a discrete card with a PCIe 4.0 x16 interface. The 840M's display outputs are "Portable Device Dependent," meaning they vary by laptop design, whereas the RX 7800 XT provides 1x HDMI 2.1a and 3x DisplayPort 2.1 outputs. Both support DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Specification Differences

The specification gap between these two GPUs is vast. The RX 7800 XT features 3840 shading units, 240 texture mapping units, and 96 render output units. The 840M has 256 shading units, 16 TMUs, and 8 ROPs. This represents a 15x difference in shader count, a 15x difference in TMUs, and a 12x difference in ROPs.

Memory configurations differ completely. The RX 7800 XT has 16 GB of GDDR6 memory on a 256-bit bus with 624.1 GB/s bandwidth. The 840M uses system-shared memory with a system-dependent bandwidth figure. The RX 7800 XT's memory clock is 2438 MHz (19.5 Gbps effective), while the 840M's memory clock is listed as "System Shared."

Clock speeds show an interesting inversion. The 840M has a higher boost clock at 2900 MHz versus 2430 MHz for the RX 7800 XT, but the RX 7800 XT has a much higher base clock at 1295 MHz versus 400 MHz. The RX 7800 XT also has a game clock of 2124 MHz, a figure the 840M does not list.

Pixel and texture rates further illustrate the performance gap. The RX 7800 XT achieves 233.3 GPixel/s and 583.2 GTexel/s, while the 840M manages 23.20 GPixel/s and 46.40 GTexel/s. FP32 throughput is 37.32 TFLOPS for the RX 7800 XT versus 1,484.8 GFLOPS for the 840M, with both offering 1:1 FP16 ratios.

Power and physical specifications diverge sharply. The RX 7800 XT has a 263 W TDP, occupies a dual-slot form factor, measures 267 mm in length, 111 mm in height, and 50 mm in width, and requires two 8-pin power connectors with a suggested 600 W PSU. The 840M has a 15 W TDP, is classified as an IGP with no slot width, requires no power connectors, and has no recorded dimensions.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark results between the 840M and RX 7800 XT. The wins counter shows 0 for both GPUs, and the headToHeadBenchmarks array is empty. Consequently, this analysis relies on the RX 7800 XT's recorded benchmark scores and the 840M's complete lack of benchmark data.

The RX 7800 XT's benchmark results provide a clear picture of its capabilities. In PassMark G3D, it scores 24,176. In Geekbench Vulkan, it achieves 54,228. Geekbench OpenCL shows 18,290. The 3DMark Steel Nomad DX12 test yields 4,157. PassMark GPU Compute records 13,473. Legacy DirectX tests show 304 in DirectX 9, 249 in DirectX 11, 121 in DirectX 10, and 93 in DirectX 12, while PassMark G2D scores 1,177.

Its average benchmark score of 11,627 places it at the 51st percentile of all GPUs. The nearest rivals in the database are the AMD Radeon RX 6500 XT with an average score of 11,842 (1.8% faster), the NVIDIA GeForce GTX 1660 with 11,680 (0.5% faster), the AMD Radeon Pro 5500M with 11,528 (0.9% slower), and the NVIDIA Tesla K20c with 11,479 (1.3% slower). These deltas are all within 2%, indicating the RX 7800 XT sits in a tightly contested performance band among these particular GPUs.

The 840M has no benchmark scores, no average score, and no nearest rivals listed. Its percentile of 50 is derived from specification analysis rather than measured performance. This absence of data means the database cannot quantify its real-world performance relative to any other GPU.

Where Each One Wins

The RX 7800 XT wins in every scenario where measured performance matters. Its 37.32 TFLOPS FP32 throughput, 233.3 GPixel/s pixel rate, and 583.2 GTexel/s texture rate make it suitable for high-fidelity gaming, 3D rendering, video editing, and compute workloads. The 60 RT cores provide substantial ray tracing capability, and the 16 GB GDDR6 frame buffer with 624.1 GB/s bandwidth supports large textures and high-resolution assets without memory pressure. Its dual-slot design and 263 W TDP reflect a component designed for desktop systems with adequate cooling and power delivery.

The 840M wins only in scenarios involving power efficiency, portability, and physical footprint. Its 15 W TDP allows it to operate within the thermal and power constraints of a laptop or compact portable device. The system-shared memory eliminates the need for dedicated VRAM, reducing cost and complexity in the host system. Its PCIe 4.0 x8 interface, while narrower than the RX 7800 XT's x16 link, is appropriate for an integrated solution. The 4 RT cores and 1,484.8 GFLOPS of FP32 performance are sufficient for basic display output, video playback, and light 2D workloads, but the data offers no evidence of capability beyond that.

The 840M's higher boost clock of 2900 MHz does not translate into practical performance advantages given its limited shader count and memory bandwidth. The RX 7800 XT's lower boost clock but vastly larger execution resources produce the benchmark scores that define its position in the database. For any workload requiring more than basic graphical output, the RX 7800 XT is the only viable option between these two based on the recorded measurements.