AMD Instinct MI300X vs AMD Radeon RX 7800M Comparison

FAQ

Q: What are the core architectural identities of the AMD Instinct MI300X and the AMD Radeon RX 7800M?

A: The MI300X is built on CDNA 3.0 with the Aqua Vanjaram chip, while the RX 7800M uses RDNA 3.0 with the Navi 32 chip. Both are manufactured on a 5 nm process at TSMC.

Q: How do the memory subsystems differ between these two GPUs?

A: The MI300X carries 192 GB of HBM3 on an 8192-bit bus delivering 5.32 TB/s of bandwidth. The RX 7800M has 12 GB of GDDR6 on a 192-bit bus with 432.0 GB/s of bandwidth.

Q: Which GPU has higher raw compute throughput in FP32?

A: The MI300X records 81.72 TFLOPS FP32, compared to 35.87 TFLOPS for the RX 7800M. Both deliver FP16 at a 1:1 ratio with their FP32 figures.

Q: What benchmark data exists for direct comparison between the two?

A: The only shared benchmark is Geekbench OpenCL, where the MI300X scores 317994 against the RX 7800M's 120778, a 163.3% delta in favor of the MI300X.

Q: How does the RX 7800M rank among all GPUs compared to the MI300X?

A: The MI300X sits at the 100th percentile of all GPUs in the database, while the RX 7800M is at the 73rd percentile. The MI300X's nearest rivals include the NVIDIA H200 NVL and NVIDIA B200, while the RX 7800M sits near the AMD Radeon Pro Vega 20 and NVIDIA GeForce GTX 980 Ti.

Q: What are the power draw specifications for each card?

A: The MI300X has a TDP of 750 W with a suggested PSU of 1150 W. The RX 7800M has a TDP of 180 W and no suggested PSU listed.

Where Each One Wins

The benchmark data presents a clear split between these two products, but the wins are contextual rather than universal. The MI300X takes the single shared benchmark, Geekbench OpenCL, with a score of 317994 versus 120778 for the RX 7800M. That 163.3% advantage reflects the MI300X's design purpose: massive parallel compute for data center workloads. The MI300X also holds the 100th percentile position across all GPUs in the database, meaning no recorded GPU scores higher on average.

The RX 7800M, however, claims victories in areas the MI300X cannot even contest. The MI300X lists no display outputs, no DirectX support, no OpenGL support, and no Vulkan support. Its pixel rate is recorded as 0 MPixel/s. The RX 7800M, by contrast, supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4, and delivers a pixel rate of 224.2 GPixel/s with 96 ROPs. In any scenario requiring graphical output, rasterization, or consumer API compatibility, the RX 7800M is the only functional choice. The MI300X wins compute density; the RX 7800M wins every graphics-related category by default.

The RX 7800M also holds advantages in clock speeds. Its base clock is 1295 MHz and boost clock is 2335 MHz, with a game clock of 2145 MHz. The MI300X runs a 1000 MHz base and 2100 MHz boost. While the MI300X compensates with vastly more execution units, the RX 7800M's higher clocks benefit latency-sensitive workloads that cannot scale across thousands of cores.

Architecture Differences

The MI300X uses CDNA 3.0, AMD's compute-optimized architecture designed for data center acceleration. The RX 7800M uses RDNA 3.0, the graphics-focused architecture that powers AMD's consumer and mobile Radeon parts. This fundamental split drives nearly every other difference between the two.

The MI300X packs 153,000 million transistors on a 1017 mm² die, yielding a transistor density of 150.4M per mm². The RX 7800M contains 28,100 million transistors on a 346 mm² die, with a density of 81.2M per mm². The MI300X's die is nearly three times larger and holds over five times the transistor count, but the RX 7800M's lower density suggests a design tuned for power efficiency and mobile thermal constraints.

Shading unit counts diverge sharply. The MI300X has 19,456 shading units, 1,216 TMUs, and zero ROPs. The RX 7800M has 3,840 shading units, 240 TMUs, and 96 ROPs. The MI300X also lists 60 ray tracing cores on the RX 7800M, while the MI300X has no ray tracing cores recorded. The MI300X's texture rate is 2,553.6 GTexel/s versus 560.4 GTexel/s for the RX 7800M, but the RX 7800M's pixel rate of 224.2 GPixel/s stands against the MI300X's 0 MPixel/s.

Memory architecture reflects the divergent purposes. The MI300X uses HBM3 with 192 GB capacity and 5.32 TB/s bandwidth, a configuration for holding large models and datasets on-chip. The RX 7800M uses GDDR6 with 12 GB capacity and 432.0 GB/s bandwidth, suited for frame buffers and real-time rendering. The MI300X's 8192-bit memory bus dwarfs the RX 7800M's 192-bit bus, which explains the bandwidth gap.

The bus interfaces also differ: the MI300X uses PCIe 5.0 x16, while the RX 7800M uses PCIe 4.0 x16. The MI300X is an OAM module with no power connectors and no display outputs. The RX 7800M is an IGP (integrated graphics processor) with display outputs described as portable device dependent.

Specification Differences

The two GPUs differ across nearly every measurable specification. Process node and foundry are identical (5 nm, TSMC), but that is where the similarities end.

The MI300X has a 1000 MHz base clock and 2100 MHz boost clock. The RX 7800M runs higher at 1295 MHz base and 2335 MHz boost, plus a 2145 MHz game clock. Memory clocks also differ: the MI300X runs at 1300 MHz with 5.2 Gbps effective, while the RX 7800M runs at 2250 MHz with 18 Gbps effective.

Memory capacity is 192 GB for the MI300X versus 12 GB for the RX 7800M. Memory type is HBM3 versus GDDR6. Bus width is 8192 bit versus 192 bit. Bandwidth is 5.32 TB/s versus 432.0 GB/s.

Compute resources: 19,456 shading units versus 3,840, 1,216 TMUs versus 240, and 0 ROPs versus 96. Ray tracing cores exist only on the RX 7800M (60). FP32 output is 81.72 TFLOPS versus 35.87 TFLOPS; FP16 matches at the same figures with 1:1 ratios. Pixel rate is 0 MPixel/s versus 224.2 GPixel/s. Texture rate is 2,553.6 GTexel/s versus 560.4 GTexel/s.

Power and physical specs: TDP is 750 W versus 180 W. The MI300X requires a 1150 W suggested PSU; the RX 7800M has none listed. The MI300X is an OAM module with no power connectors; the RX 7800M is an IGP with no power connectors. The MI300X has no display outputs; the RX 7800M's outputs are portable device dependent.

API support: the MI300X lists N/A for DirectX, OpenGL, and Vulkan. The RX 7800M supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Release timing: the MI300X launched on 2023-12-05, the RX 7800M on 2024-09-10. The MI300X's predecessor is Radeon Instinct, while the RX 7800M succeeds Polaris Mobile.

Head-to-Head Benchmarks

The database contains one direct benchmark comparison between these two GPUs: Geekbench OpenCL. The MI300X scores 317994, while the RX 7800M scores 120778. That gives the MI300X a 163.3% advantage, the largest single-benchmark delta recorded between the pair.

Context from the nearest rivals clarifies the MI300X's standing. The NVIDIA H200 NVL scores 334891, which is 5% above the MI300X. The NVIDIA B200 scores 345482, 8% above. The NVIDIA L40S scores 295763, 7.5% below the MI300X. The NVIDIA RTX 6000 Ada Generation scores 287237, 10.7% below. The MI300X's 317994 OpenCL score places it near the top of the data center GPU tier, trailing only the H200 NVL and B200 among recorded rivals.

The RX 7800M's nearest rivals paint a different picture. The AMD Radeon Pro Vega 20 scores 27839, just 0.2% below the RX 7800M's 27883 average. The AMD Radeon Pro W5500X scores 27973, 0.3% above. The NVIDIA GeForce GTX 980 Ti scores 28020, 0.5% above. The AMD FirePro S7150 scores 28117, 0.8% above. The RX 7800M sits in a tightly packed cluster of mid-range GPUs, with less than 1% separating it from its closest competitors.

The RX 7800M has its own benchmark suite beyond the shared OpenCL test. Its 3DMark Steel Nomad DX12 score is 2994. In PassMark tests, it records 17613 in G3D, 9342 in GPU Compute, 892 in G2D, 176 in DirectX 11, 174 in DirectX 9, 99 in DirectX 10, and 89 in DirectX 12. Geekbench Vulkan scores 126668. These figures give the RX 7800M a 73rd percentile ranking across all GPUs, with an average benchmark score of 27883.

The MI300X's average benchmark score is 317994, matching its single recorded OpenCL result, and it holds the 100th percentile position. The gap between the two GPUs in raw compute is enormous, but the benchmark coverage reflects their distinct roles. The MI300X has no graphics benchmarks because it has no graphics pipeline. The RX 7800M has no data center scale benchmark results because it is not designed for that workload class.

The data supports a straightforward interpretation: the MI300X dominates in compute-focused OpenCL performance by 163.3%, while the RX 7800M offers the only path to graphics APIs, display output, and rasterization. Each GPU wins the categories its architecture targets, and the shared benchmark shows the compute chasm between them.