AMD Instinct MI300X vs AMD Radeon RX 6850M XT Comparison

Head-to-Head Benchmarks

The recorded data contains a single head-to-head benchmark result between these two parts, and it is decisively one-sided. In the Geekbench OpenCL test, the AMD Instinct MI300X scores 317,994, while the AMD Radeon RX 6850M XT scores 85,040. That is a delta of 273.9% in favor of the Instinct MI300X, meaning the data center accelerator delivers roughly 3.7 times the raw compute throughput of the mobile graphics chip in this workload.

This is not a marginal victory. The MI300X's OpenCL score places it at the 100th percentile of all GPUs in the database, while the RX 6850M XT sits at the 92nd percentile. Both are high performers in absolute terms, but the gap between them is enormous. To put it in context, the MI300X's nearest rivals are all NVIDIA data center parts: the B200 at 345,482 (8% above the MI300X), the H200 NVL at 334,891 (5% above), the L40S at 295,763 (7.5% below), and the RTX 6000 Ada Generation at 287,237 (10.7% below). The RX 6850M XT, by contrast, competes in a much lower tier, with nearest rivals including the NVIDIA Tesla P100 PCIe 12 GB at 79,396 (0.6% below), the Tesla P100 PCIe 16 GB at 79,605 (0.8% below), the GeForce RTX 5090 at 79,842 (1.1% below), and the RTX 5090 D at 77,712 (1.6% above).

The head-to-head delta of 273.9% is far larger than any gap seen among the MI300X's own rival group. The largest delta in that group is 10.7%, between the MI300X and the RTX 6000 Ada. The RX 6850M XT's rival group shows deltas of only 0.6% to 1.6%, indicating a tightly clustered field. This contrast underscores that the two AMD parts are not merely different in performance tier; they are operating in entirely separate competitive arenas.

The RX 6850M XT does have additional benchmark results in the database that the MI300X lacks: a 3DMark Steel Nomad DX12 score of 2,257, a Geekbench Metal score of 128,981, and a Geekbench Vulkan score of 99,483. However, no equivalent tests were run on the MI300X, so direct comparisons on those workloads are not possible from the recorded data. What can be said is that the MI300X's single OpenCL result is so dominant that no other benchmark is needed to establish which part has the higher raw compute ceiling.

Architecture Differences

The fundamental architectural split is between CDNA 3.0 and RDNA 2.0. The MI300X uses AMD's CDNA 3.0 architecture, built on a 5 nm process at TSMC, while the RX 6850M XT uses RDNA 2.0 on a 7 nm node, also at TSMC. This process gap alone explains a substantial portion of the performance difference, as the 5 nm node allows for dramatically higher transistor density.

The transistor counts are staggering in their disparity. The MI300X integrates 153,000 million transistors on a 1017 mm² die, yielding a density of 150.4 million transistors per square millimeter. The RX 6850M XT has 17,200 million transistors on a 335 mm² die, with a density of 51.3 million per square millimeter. That is roughly nine times more transistors in the MI300X, on a die three times larger, with nearly three times the density.

The chips themselves are named Aqua Vanjaram (MI300X) and Navi 22 (RX 6850M XT). The MI300X belongs to the Instinct (MIx) generation, while the RX 6850M XT is part of the Navi Mobile (RX 6000M) generation. The MI300X's predecessor is listed as Radeon Instinct, and the RX 6850M XT's predecessor is Polaris Mobile.

Memory configurations diverge completely. The MI300X packs 192 GB of HBM3 on an 8192-bit bus, delivering 5.32 TB/s of bandwidth. The RX 6850M XT has 12 GB of GDDR6 on a 192-bit bus, with 432.0 GB/s of bandwidth. The MI300X's memory bandwidth is more than twelve times higher, and its capacity is sixteen times larger.

Compute resources follow the same pattern. The MI300X has 19,456 shading units and 1,216 texture mapping units, but zero ROPs, reflecting its compute-first design with no display output. The RX 6850M XT has 2,560 shading units, 160 TMUs, and 64 ROPs, plus 40 ray tracing cores. The MI300X has no ray tracing cores listed. Pixel rate for the MI300X is 0 MPixel/s, while the RX 6850M XT delivers 165.2 GPixel/s. Texture rates are 2,553.6 GTexel/s for the MI300X versus 413.0 GTexel/s for the RX 6850M XT.

FP32 throughput is 81.72 TFLOPS for the MI300X and 13.21 TFLOPS for the RX 6850M XT. FP16 is also 81.72 TFLOPS (1:1 ratio) for the MI300X, while the RX 6850M XT achieves 26.43 TFLOPS at a 2:1 ratio. The MI300X has no API support listed (DirectX, OpenGL, Vulkan all N/A), because it is not designed for graphics rendering. The RX 6850M XT supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Clock speeds also differ: the MI300X runs at 1000 MHz base and 2100 MHz boost, while the RX 6850M XT runs at 2321 MHz base and 2581 MHz boost. The mobile part has higher clocks, but the MI300X compensates with vastly more compute units. Memory clocks are 1300 MHz (5.2 Gbps effective) for the MI300X versus 2250 MHz (18 Gbps effective) for the RX 6850M XT.

FAQ

Q: Which GPU has the higher OpenCL benchmark score?

A: The AMD Instinct MI300X scores 317,994 in Geekbench OpenCL, which is 273.9% higher than the AMD Radeon RX 6850M XT's score of 85,040.

Q: What is the memory capacity difference between the two?

A: The MI300X has 192 GB of HBM3 memory, while the RX 6850M XT has 12 GB of GDDR6. The MI300X also has a much wider 8192-bit bus versus the RX 6850M XT's 192-bit bus.

Q: Do both GPUs support ray tracing?

A: The RX 6850M XT has 40 ray tracing cores and supports DirectX 12 Ultimate. The MI300X lists no ray tracing cores and has no API support for DirectX, OpenGL, or Vulkan, as it is designed for compute workloads.

Q: Which GPU uses a smaller manufacturing process?

A: The MI300X is built on a 5 nm process at TSMC, while the RX 6850M XT uses a 7 nm process, also at TSMC.

Q: What is the power consumption difference?

A: The MI300X has a TDP of 750 W, while the RX 6850M XT has a TDP of 165 W. The MI300X also suggests a 1150 W power supply, while the RX 6850M XT has no suggested PSU listed.

Q: Are there any benchmark tests where the RX 6850M XT wins?

A: In the recorded head-to-head data, the MI300X wins the only shared benchmark (Geekbench OpenCL). The RX 6850M XT has additional scores in 3DMark Steel Nomad DX12 (2,257), Geekbench Metal (128,981), and Geekbench Vulkan (99,483), but the MI300X has no corresponding results for those tests.

Specification Differences

| Field | AMD Instinct MI300X | AMD Radeon RX 6850M XT |

|-------|---------------------|------------------------|

| Architecture | CDNA 3.0 | RDNA 2.0 |

| Process Node | 5 nm | 7 nm |

| Transistors | 153,000 million | 17,200 million |

| Die Size | 1017 mm² | 335 mm² |

| Transistor Density | 150.4M / mm² | 51.3M / mm² |

| Base Clock | 1000 MHz | 2321 MHz |

| Boost Clock | 2100 MHz | 2581 MHz |

| Memory Size | 192 GB | 12 GB |

| Memory Type | HBM3 | GDDR6 |

| Memory Bus | 8192 bit | 192 bit |

| Memory Bandwidth | 5.32 TB/s | 432.0 GB/s |

| Shading Units | 19,456 | 2,560 |

| TMUs | 1,216 | 160 |

| ROPs | 0 | 64 |

| RT Cores | N/A | 40 |

| Pixel Rate | 0 MPixel/s | 165.2 GPixel/s |

| Texture Rate | 2,553.6 GTexel/s | 413.0 GTexel/s |

| FP32 | 81.72 TFLOPS | 13.21 TFLOPS |

| FP16 | 81.72 TFLOPS (1:1) | 26.43 TFLOPS (2:1) |

| TDP | 750 W | 165 W |

| Slot Width | OAM Module | IGP |

| Bus Interface | PCIe 5.0 x16 | PCIe 4.0 x16 |

| Display Outputs | No outputs | Portable Device Dependent |

| DirectX | N/A | 12 Ultimate (12_2) |

| OpenGL | N/A | 4.6 |

| Vulkan | N/A | 1.4 |

| Release Date | 2023-12-05 | 2022-01-03 |

| Production Status | Not listed | End-of-life |

The Verdict

The data is unambiguous. The AMD Instinct MI300X is a compute accelerator with a 273.9% OpenCL advantage over the AMD Radeon RX 6850M XT, placing it at the 100th percentile of all GPUs. The RX 6850M XT, at the 92nd percentile, is a strong mobile GPU but is outclassed by an order of magnitude in raw throughput.

The MI300X is designed for data center workloads: 192 GB of HBM3 with 5.32 TB/s bandwidth, 81.72 TFLOPS of FP32, no display outputs, no graphics API support, and a 750 W TDP. The RX 6850M XT is a mobile part with 12 GB of GDDR6, 13.21 TFLOPS of FP32, 40 ray tracing cores, full DirectX 12 Ultimate support, and a 165 W TDP. These are not competing products in any meaningful sense. One is a server accelerator, the other is a laptop GPU.

The nearest rival data reinforces this separation. The MI300X competes against NVIDIA's H200 NVL, B200, L40S, and RTX 6000 Ada Generation, all with average scores between 287,237 and 345,482. The RX 6850M XT competes against Tesla P100 variants and GeForce RTX 5090 variants, with average scores between 77,712 and 79,842. The MI300X's rivals are 3.6 to 4.3 times faster than the RX 6850M XT's rivals.

Where Each One Wins

The MI300X wins decisively in any compute-heavy workload that can leverage massive parallelism. Its 273.9% OpenCL advantage, combined with 192 GB of HBM3 memory and 81.72 TFLOPS of FP32, makes it the choice for large-scale inference, training, scientific simulation, or any task where memory capacity and bandwidth are the limiting factors. Its 100th percentile ranking means it outperforms virtually every other GPU in the database on the recorded OpenCL test. The 5 nm process and 153,000 million transistors provide the raw foundation for this dominance.

The RX 6850M XT wins in the domains of graphics rendering and mobile deployment. It has 64 ROPs and a 165.2 GPixel/s pixel rate, compared to zero for the MI300X. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, none of which the MI300X supports. It has 40 ray tracing cores for real-time ray tracing. Its 165 W TDP and IGP form factor make it suitable for a laptop, while the MI300X is an OAM module with no display outputs and a 750 W TDP. The RX 6850M XT also has higher clock speeds (2321 MHz base, 2581 MHz boost), which benefit latency-sensitive workloads that do not scale across thousands of cores.

The RX 6850M XT's additional benchmark results, including a 3DMark Steel Nomad DX12 score of 2,257 and a Geekbench Vulkan score of 99,483, demonstrate capability in graphics-focused tests. Its Geekbench Metal score of 128,981 is notably higher than its OpenCL score, suggesting the part performs relatively better on Apple's Metal API. However, since the MI300X has no equivalent results for these tests, any comparison on those workloads would be speculative.

In summary, the MI300X is the winner for pure compute density and memory-bound tasks. The RX 6850M XT is the winner for graphics rendering, ray tracing, and mobile applications. Users requiring both capabilities would need to deploy both parts, as neither can substitute for the other's core strengths.