AMD Instinct MI300X vs AMD Radeon PRO W6800 Comparison

The AMD Instinct MI300X and the AMD Radeon PRO W6800 serve entirely different purposes, and the benchmark data reflects that stark divide. The MI300X is a data-center compute monster, delivering a Geekbench OpenCL score of 317,994, which places it in the 100th percentile of all GPUs. The W6800, by contrast, is a professional workstation card with an average benchmark score of 135,396 (96th percentile), trailing the MI300X by a massive 161.1% in their shared OpenCL test. The verdict is simple: if your workload is raw, massive-scale compute and memory capacity, the MI300X is the only choice. If you need a professional GPU with display outputs, standard PCIe power connectors, and a physical card that fits in a workstation, the W6800 is the one, despite its far lower compute output.

The Verdict

Choose the AMD Instinct MI300X if: your primary metric is peak compute throughput or memory bandwidth. It delivers 81.72 TFLOPS of FP32 performance and 81.72 TFLOPS of FP16 (1:1), compared to the W6800’s 17.83 TFLOPS FP32 and 35.67 TFLOPS FP16 (2:1). In OpenCL, the MI300X scores 317,994 against the W6800’s 121,808, a 161.1% advantage. This card is also the clear winner on memory: 192 GB of HBM3 with 5.32 TB/s bandwidth versus 32 GB of GDDR6 with 512.0 GB/s. The MI300X also ranks 7.5% above the NVIDIA L40S and 10.7% above the NVIDIA RTX 6000 Ada Generation in average score, placing it in elite accelerators’ territory.

Choose the AMD Radeon PRO W6800 if: you need a GPU that behaves like a conventional graphics card. It has a dual-slot form factor, 6x mini-DisplayPort 1.4a outputs, and a 1x 6-pin + 1x 8-pin power connector setup with a 600 W suggested PSU. It also supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4—APIs the MI300X does not support at all. The W6800’s nearest rivals are the NVIDIA A10M and RTX 4000 Ada Generation, both within 0.1% of its average score, so it’s a solid mid-tier professional card. Its 96th percentile ranking is respectable, but it is nowhere near the MI300X’s performance class. The W6800 is end-of-life, which is a consideration for longevity.

Where Each One Wins

The MI300X wins decisively in raw compute and memory. Its 5.32 TB/s memory bandwidth is over ten times the W6800’s 512.0 GB/s, and its 192 GB capacity dwarfs the 32 GB on the W6800. For large model inference or training, that memory advantage is not incremental—it’s the difference between fitting a workload and not. The MI300X also wins in texture rate (2,553.6 GTexel/s vs 557.3 GTexel/s) and FP32 throughput (81.72 vs 17.83 TFLOPS). Its 100th percentile rank means it outperforms all other GPUs in the database, including the NVIDIA B200 (8% higher score than the MI300X, but the MI300X still sits above it in percentile). The single head-to-head benchmark, Geekbench OpenCL, is a clean sweep for the MI300X.

The W6800 wins in practical workstation usability. It has display outputs, which the MI300X lacks entirely—the Instinct card has "No outputs" listed. The W6800 also has a conventional dual-slot design with a 267 mm length, 120 mm height, and 50 mm width, fitting in standard workstation chassis. Its 250 W TDP and 600 W suggested PSU are far more manageable than the MI300X’s 750 W TDP and 1150 W suggested PSU. The W6800 also supports modern graphics APIs, making it usable for rendering or any task that requires DirectX, OpenGL, or Vulkan. It also has 60 ray-tracing cores, which the MI300X does not list. The W6800’s nearest rivals are within 0.1% to 0.8% of its score, showing it’s a competitive card in its own class—just not the MI300X’s class.

Architecture Differences

The MI300X is built on CDNA 3.0 architecture (chip codename Aqua Vanjaram), while the W6800 uses RDNA 2.0 (Navi 21). This is a fundamental split: CDNA is AMD’s compute-optimized architecture, while RDNA is graphics-oriented. The process nodes differ, with the MI300X on TSMC’s 5 nm process and the W6800 on 7 nm. The MI300X packs 153,000 million transistors on a 1017 mm² die, achieving a density of 150.4M transistors per mm². The W6800 has 26,800 million transistors on a 520 mm² die, with a density of 51.5M per mm². That’s a 5.7x transistor count difference.

Memory architectures are completely different. The MI300X uses HBM3 with an 8192-bit bus, while the W6800 uses GDDR6 with a 256-bit bus. This explains the bandwidth gap: 5.32 TB/s versus 512.0 GB/s. Clock speeds also tell a story: the MI300X has a 1000 MHz base and 2100 MHz boost, while the W6800 boosts higher to 2322 MHz. The W6800’s higher clocks are typical of a graphics card optimized for latency-sensitive tasks, while the MI300X relies on massive parallelism. The MI300X has 19,456 shading units and 1,216 TMUs, but 0 ROPs and 0 pixel rate—it’s not designed to output pixels. The W6800 has 3,840 shading units, 240 TMUs, and 96 ROPs, with a 222.9 GPixel/s pixel rate. The MI300X has no API support (DirectX, OpenGL, Vulkan all N/A), while the W6800 supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4.

FAQ

Q: Which card is faster in OpenCL?

A: The AMD Instinct MI300X scores 317,994 in Geekbench OpenCL, which is 161.1% higher than the Radeon PRO W6800’s 121,808. The MI300X also ranks in the 100th percentile of all GPUs, while the W6800 sits in the 96th.

Q: Can I connect a monitor to either card?

A: No for the MI300X—it has no display outputs. Yes for the W6800, which features 6x mini-DisplayPort 1.4a outputs. The MI300X is an OAM Module with no pixel rate, making it unsuitable for any display task.

Q: Which card has more memory bandwidth?

A: The MI300X has 5.32 TB/s of bandwidth from 192 GB of HBM3 on a 8192-bit bus. The W6800 has 512.0 GB/s from 32 GB of GDDR6 on a 256-bit bus. The MI300X’s bandwidth is more than ten times higher.

Q: What are the power requirements?

A: The MI300X has a 750 W TDP and requires a 1150 W suggested PSU, with no power connectors on the card itself (it uses an OAM Module interface). The W6800 has a 250 W TDP with a 600 W suggested PSU and uses standard 1x 6-pin + 1x 8-pin connectors.

Q: Which card supports ray tracing?

A: The W6800 has 60 ray-tracing cores and supports DirectX 12 Ultimate. The MI300X does not list any ray-tracing cores, and its DirectX support is N/A.

Q: What is the transistor density difference?

A: The MI300X has a density of 150.4 million transistors per mm², while the W6800 has 51.5 million per mm². The MI300X uses a 5 nm process with 153,000 million transistors, while the W6800 uses 7 nm with 26,800 million.

Head-to-Head Benchmarks

The only shared benchmark is Geekbench OpenCL, and it is a blowout. The MI300X scores 317,994, while the W6800 scores 121,808. That’s a delta of 161.1% in favor of the MI300X. To put that in context, the MI300X’s nearest rival is the NVIDIA H200 NVL, which scores 334,891—the MI300X is only 5% behind that, but 7.5% ahead of the NVIDIA L40S and 10.7% ahead of the NVIDIA RTX 6000 Ada Generation. The W6800’s nearest rival is the NVIDIA A10M at 135,230 (0.1% behind) and the AMD Radeon Pro W6800X Duo at 135,774 (0.3% ahead). The gap between the MI300X and the W6800 is not a close race; it’s a different league.

The MI300X also wins on raw throughput metrics that aren’t directly benchmarked but derived from specs. Its FP32 of 81.72 TFLOPS is 4.6 times the W6800’s 17.83 TFLOPS. Its FP16 of 81.72 TFLOPS (1:1) is 2.3 times the W6800’s 35.67 TFLOPS (2:1). Texture rate is 2,553.6 GTexel/s versus 557.3 GTexel/s. The W6800 does win on pixel rate (222.9 GPixel/s vs 0 MPixel/s) and boost clock (2322 MHz vs 2100 MHz), but those are irrelevant for compute-focused workloads. The MI300X wins 1 out of 1 head-to-head benchmarks, and the W6800 wins 0.

Specification Differences

The two cards differ in nearly every measurable specification. Chip and process: MI300X uses Aqua Vanjaram on CDNA 3.0 at 5 nm; W6800 uses Navi 21 on RDNA 2.0 at 7 nm. Transistors: 153,000 million vs 26,800 million. Die size: 1017 mm² vs 520 mm². Transistor density: 150.4M / mm² vs 51.5M / mm². Clocks: MI300X base 1000 MHz / boost 2100 MHz; W6800 base 1575 MHz / boost 2322 MHz. Memory: 192 GB HBM3 vs 32 GB GDDR6; 8192-bit vs 256-bit bus; 5.32 TB/s vs 512.0 GB/s bandwidth. Shading units: 19,456 vs 3,840. TMUs: 1,216 vs 240. ROPs: 0 vs 96. Ray tracing cores: none vs 60. Pixel rate: 0 MPixel/s vs 222.9 GPixel/s. Texture rate: 2,553.6 GTexel/s vs 557.3 GTexel/s. FP32: 81.72 TFLOPS vs 17.83 TFLOPS. FP16: 81.72 TFLOPS (1:1) vs 35.67 TFLOPS (2:1). TDP: 750 W vs 250 W. Slot width: OAM Module vs Dual-slot. Power connectors: None vs 1x 6-pin + 1x 8-pin. Suggested PSU: 1150 W vs 600 W. Bus interface: PCIe 5.0 x16 vs PCIe 4.0 x16. Display outputs: No outputs vs 6x mini-DisplayPort 1.4a. APIs: N/A vs DirectX 12 Ultimate, OpenGL 4.6, Vulkan 1.4. Dimensions: W6800 is 267 mm x 120 mm x 50 mm; MI300X dimensions are not listed. Release date: MI300X on 2023-12-05 vs W6800 on 2021-06-07. Production status: MI300X not listed vs W6800 end-of-life. Launch MSRP: W6800 at 2,249 USD; MI300X has no listed MSRP. Benchmarks: MI300X has one OpenCL score (317,994); W6800 has three scores (OpenCL 121,808, Metal 174,420, Vulkan 109,961).