AMD Instinct MI100 vs AMD Radeon Pro W6800X Comparison

AMD Radeon Pro W6800X and AMD Instinct MI100 are both end-of-life AMD accelerators built on a 7 nm TSMC process, but they target fundamentally different workloads. The data shows the Instinct MI100 holds a clear performance edge in the single shared benchmark, while the Radeon Pro W6800X counters with a much higher clock speed, a full display output suite, and broader API support. The average benchmark scores place the W6800X at 160,671 (97th percentile) versus 139,035 (96th percentile) for the MI100, but the head-to-head OpenCL result tells a different story.

FAQ

Q: Which card wins in the direct head-to-head OpenCL benchmark?

A: The AMD Instinct MI100 wins the geekbench_opencl test with a score of 139,035, beating the Radeon Pro W6800X's 124,498 by 10.5%.

Q: How do the two cards compare in average benchmark score?

A: The Radeon Pro W6800X has a higher average benchmark score of 160,671, while the Instinct MI100 averages 139,035. The W6800X sits at the 97th percentile of all GPUs, and the MI100 at the 96th.

Q: What are the nearest rivals for each card based on average score?

A: The W6800X's closest rival is the NVIDIA A100 PCIe 40 GB, which scores 162,504 and is 1.1% ahead. The MI100's closest rival is the NVIDIA Tesla V100 PCIe 16 GB, which scores 138,063 and is 0.7% behind.

Q: Do both cards have the same memory capacity?

A: Yes, both have 32 GB of memory, but the W6800X uses GDDR6 on a 256-bit bus while the MI100 uses HBM2 on a 4096-bit bus.

Q: Which card supports display outputs?

A: The Radeon Pro W6800X features 1x HDMI 2.1 and 4x Thunderbolt outputs. The Instinct MI100 has no display outputs at all.

Q: What is the difference in thermal design power?

A: The Radeon Pro W6800X has a 200 W TDP, while the Instinct MI100 has a 300 W TDP. The MI100 also requires a 700 W suggested PSU versus 550 W for the W6800X.

Architecture Differences

The two accelerators diverge sharply in architecture, reflecting their distinct design goals. The Radeon Pro W6800X uses the Navi 21 chip based on RDNA 2.0, a graphics-first architecture. The Instinct MI100 uses the Arcturus chip based on CDNA 1.0, a compute-optimized design with no graphics pipeline. Both are fabricated on TSMC's 7 nm process, but the transistor counts and die sizes tell a different story: the W6800X packs 26,800 million transistors on a 520 mm² die (51.5 million per mm²), while the MI100 has 25,600 million transistors on a much larger 750 mm² die (34.1 million per mm²). The larger die with fewer transistors per area suggests the MI100 prioritizes compute density over power efficiency.

Clock speeds are dramatically different. The W6800X runs at a base clock of 1800 MHz and boosts to 2087 MHz, whereas the MI100 has a base of 1000 MHz and a boost of 1502 MHz. The RDNA 2.0 card also carries 60 ray tracing cores, while the CDNA 1.0 card has none. The shading unit counts flip the narrative: the MI100 has 7680 shading units, 480 texture mapping units, and 64 ROPs, versus 3840 shading units, 240 TMUs, and 96 ROPs for the W6800X. The MI100's higher stream processor count, combined with its massive 4096-bit HBM2 memory bus, points to raw compute throughput, while the W6800X's higher clocks and ray tracing hardware target graphics workloads.

The API support also differentiates them. The W6800X supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI100 lists N/A for DirectX, OpenGL, and Vulkan, confirming it is not a graphics card. The memory subsystem is another key split: the W6800X uses 32 GB of GDDR6 with 512.0 GB/s bandwidth, while the MI100 uses 32 GB of HBM2 with 1.23 TB/s bandwidth. The MI100's memory bandwidth is more than double, which matters for compute workloads that stream large datasets.

Head-to-Head Benchmarks

Only one benchmark is available for a direct comparison: geekbench_opencl. In this test, the AMD Instinct MI100 scores 139,035 against the Radeon Pro W6800X's 124,498, giving the MI100 a 10.5% win. This result aligns with the architectural differences: the MI100 has 7680 shading units versus 3840, and its HBM2 memory delivers 1.23 TB/s versus 512.0 GB/s. The W6800X's higher clock speed (2087 MHz boost versus 1502 MHz) cannot compensate for the MI100's doubled shader count and memory bandwidth in this raw compute test.

However, the average benchmark scores across all tests tell a different story. The W6800X's average of 160,671 is 15.6% higher than the MI100's 139,035, driven by the W6800X's additional geekbench_metal result of 196,844. The MI100 has no Metal benchmark listed, suggesting it lacks or does not optimize for that API. In the nearest rival comparisons, the W6800X trails the NVIDIA A100 PCIe 40 GB by just 1.1% (162,504) and the AMD Radeon PRO W7800 by 2.6% (164,894). The MI100 leads the Tesla V100 PCIe 16 GB by 0.7% (138,063) and the Tesla V100 SXM2 32 GB by 0.9% (137,731). The W6800X also beats the AMD Radeon Pro W6800X Duo by 2.4% (135,774) based on the MI100's rival list, though that comparison is indirect.

The FP32 and FP16 compute figures reinforce the MI100's dominance in pure math: it delivers 23.07 TFLOPS FP32 and 46.14 TFLOPS FP16 (2:1), versus 16.03 TFLOPS FP32 and 32.06 TFLOPS FP16 (2:1) for the W6800X. That is a 44% advantage in both FP32 and FP16 throughput for the MI100. The W6800X counters with higher pixel rate (200.4 GPixel/s versus 96.13 GPixel/s) but lower texture rate (500.9 GTexel/s versus 721.0 GTexel/s).

Specification Differences

The two cards differ on nearly every measurable specification. The most striking contrasts are in clock speed, memory type, and bus width. The W6800X runs at 1800 MHz base and 2087 MHz boost, while the MI100 runs at 1000 MHz base and 1502 MHz boost. Memory type is GDDR6 on the W6800X with a 256-bit bus and 512.0 GB/s bandwidth; the MI100 uses HBM2 on a 4096-bit bus with 1.23 TB/s bandwidth.

Shading units: 3840 on the W6800X versus 7680 on the MI100. TMUs: 240 versus 480. ROPs: 96 versus 64. Ray tracing cores: 60 on the W6800X, none on the MI100. The pixel rate is 200.4 GPixel/s for the W6800X and 96.13 GPixel/s for the MI100. Texture rate is 500.9 GTexel/s for the W6800X and 721.0 GTexel/s for the MI100.

FP32 performance is 16.03 TFLOPS versus 23.07 TFLOPS; FP16 is 32.06 TFLOPS versus 46.14 TFLOPS (both 2:1). TDP is 200 W versus 300 W. The W6800X is a quad-slot card using an Apple MPX power connector and bus interface, while the MI100 is dual-slot with 2x 8-pin power and PCIe 4.0 x16 bus. The W6800X has display outputs (1x HDMI 2.1, 4x Thunderbolt); the MI100 has none. The W6800X supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4; the MI100 supports none of these APIs. The W6800X measures 267 mm by 120 mm, while the MI100 is 267 mm by 111 mm. The W6800X launched on 2021-08-02 with a launch MSRP of 2,799 USD; the MI100 launched on 2020-11-15 with no MSRP listed. The MI100 has a predecessor (Radeon Instinct), while the W6800X has none.

Where Each One Wins

The AMD Instinct MI100 wins in raw compute throughput. Its 23.07 TFLOPS FP32 and 46.14 TFLOPS FP16 figures are 44% higher than the W6800X's 16.03 and 32.06 TFLOPS. The 1.23 TB/s memory bandwidth is more than double the W6800X's 512.0 GB/s, which is critical for data-intensive workloads. The MI100 also wins the only direct benchmark comparison, the geekbench_opencl test, with a 10.5% margin. Its 7680 shading units and 480 TMUs give it a clear edge in parallel compute tasks. The dual-slot form factor and standard PCIe 4.0 x16 interface make it easier to integrate into server platforms, despite the higher 300 W TDP.

The AMD Radeon Pro W6800X wins in graphics-oriented scenarios. It has display outputs (1x HDMI 2.1 and 4x Thunderbolt), which the MI100 lacks entirely. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, making it usable for gaming and professional graphics applications, while the MI100 has no such API support. The W6800X has a higher pixel rate (200.4 GPixel/s versus 96.13 GPixel/s) and 60 ray tracing cores, which are absent on the MI100. Its higher boost clock of 2087 MHz versus 1502 MHz helps in latency-sensitive tasks. The W6800X also has a lower TDP of 200 W versus 300 W, and its average benchmark score of 160,671 is 15.6% higher than the MI100's 139,035, driven by the strong geekbench_metal result of 196,844.

The Verdict

From the data, the choice depends entirely on workload. The AMD Instinct MI100 is the pick for pure compute acceleration. It wins the only head-to-head benchmark, delivers 44% higher FP32 and FP16 throughput, and offers more than double the memory bandwidth. Its 96th percentile ranking and lead over the Tesla V100 variants confirm it as a strong compute part. The lack of display outputs and graphics API support is irrelevant in a server context.

The AMD Radeon Pro W6800X is the pick for professional graphics and macOS environments. Its 97th percentile ranking, higher average benchmark score, and full display output suite make it the only viable choice for tasks that require rendering, ray tracing, or any visual output. The 2,799 USD launch MSRP reflects its workstation positioning. The Metal benchmark score of 196,844 indicates strong performance in Apple's ecosystem, which the MI100 does not address. The W6800X's lower TDP and power connector requirements also make it easier to deploy in workstation chassis.

The 10.5% deficit in OpenCL for the W6800X is a notable weakness, but it is offset by the card's versatility. For users who need both compute and graphics, the W6800X is the only option. For users who need maximum compute density and memory bandwidth in a headless server, the MI100 is superior. The data does not support a single winner; it supports two different tools for two different jobs.