AMD Instinct MI355X vs NVIDIA B200 SXM6 Comparison

The AMD Instinct MI355X and NVIDIA B200 SXM6 are both purpose-built for dense compute environments, yet they approach the same workload from opposite design philosophies. The MI355X uses a 3 nm process with a massive 2380 mm² die containing 185,000 million transistors, while the B200 SXM6 uses a 5 nm process on a 1628 mm² die with 208,000 million transistors. The density difference is stark: the B200 SXM6 packs 127.8M transistors per mm² versus 77.7M per mm² for the MI355X. That density advantage gives NVIDIA more transistors on a smaller piece of silicon, but AMD counters with a physically larger chip and a higher thermal envelope.

The MI355X draws up to 1400 W with a suggested power supply of 1800 W, while the B200 SXM6 is rated at 1000 W with a suggested 1400 W PSU. The AMD part is a full OAM module measuring 102 mm in length and 165 mm in width, whereas the B200 is an SXM module with no recorded dimensions. Neither card has display outputs, and both expose no graphics APIs, which confirms their accelerator-only status.

Head-to-Head Benchmarks

The database records no direct benchmark scores for either device. Both parts sit at the 50th percentile among all GPUs in the database, and both have an average benchmark score of zero. The absence of recorded measurements means there is no head-to-head performance data to compare directly. The wins counters are also zero for both sides.

Without raw workload scores, the analysis must rely on the architectural specifications that drive compute throughput. In FP32 and FP16 operations, the MI355X delivers 78.64 TFLOPS for both precision types at a 1:1 ratio. The B200 SXM6 delivers 69.34 TFLOPS in both FP32 and FP16, also at 1:1. That places the AMD part 13.4 percent ahead of the NVIDIA part in raw floating-point throughput. Texture rate tells a similar story: the MI355X achieves 2,457.6 GTexel/s against 1,083.4 GTexel/s for the B200, a 126.8 percent advantage. However, the B200 has a pixel rate of 43.92 GPixel/s while the MI355X is recorded at 0 MPixel/s, which indicates the AMD chip does not implement traditional pixel output in this configuration.

The MI355X has 16,384 shading units and 1,024 texture mapping units. The B200 SXM6 has 18,944 shading units, which is 15.6 percent more, but only 592 texture mapping units, which is 42.2 percent fewer. The B200 also has 24 raster output units and 592 tensor cores, while the MI355X lists no tensor core count and zero ROPs. These numbers suggest the AMD part is optimized for shader and texture throughput, while the NVIDIA part dedicates more of its silicon to shading units and tensor operations.

The transistor counts and die sizes do not translate into a simple performance hierarchy. The B200 has 12.4 percent more transistors than the MI355X, but on a 31.6 percent smaller die. The MI355X compensates with a 31.6 percent larger die and a 40 percent higher TDP. Clock speeds also differ significantly. The MI355X has a base clock of 1000 MHz and a boost of 2400 MHz. The B200 SXM6 has a base clock of just 120 MHz and a boost of 1830 MHz. The AMD chip boosts 31.1 percent higher, which explains its advantage in FP32 and FP16 throughput despite having fewer shading units.

Architecture Differences

The two accelerators come from different manufacturing generations. The MI355X uses the CDNA 4.0 architecture on a 3 nm process, fabricated by TSMC. The B200 SXM6 uses the Blackwell architecture on a 5 nm process, also from TSMC. The MI355X belongs to the Instinct (MIx) generation with the MI350 256CU chip, while the B200 is part of the Server Blackwell (Bxx) generation with the GB100 chip.

Transistor density is a key differentiator. The B200 achieves 127.8M transistors per mm², which is 64.5 percent denser than the MI355X at 77.7M per mm². That density comes from the smaller 5 nm node despite it being a larger process node than the 3 nm used by AMD. The MI355X uses a 2380 mm² die, which is 46.2 percent larger than the 1628 mm² die on the B200. The MI355X has 185,000 million transistors, while the B200 has 208,000 million, an 12.4 percent difference in NVIDIA's favor.

Memory configurations are nearly identical in bandwidth but differ in capacity. Both use HBM3e memory with an 8192 bit bus and 8.19 TB/s bandwidth. The MI355X carries 288 GB of memory, which is 60 percent more than the 180 GB on the B200 SXM6. The memory clock is the same for both: 2000 MHz with 8 Gbps effective. The extra 108 GB on the AMD part could matter for workloads that need large model residency without spilling to host memory.

The B200 SXM6 is the only one with a production status of Active. It was released on 2024-10-31, while the MI355X has no recorded production status and a release date of 2025-06-11. The B200 has a predecessor in Server Hopper and a successor in Server Rubin. The MI355X lists Radeon Instinct as its predecessor and has no successor recorded. The B200 also carries a launch MSRP of 34,999 USD, while the MI355X has no recorded launch price.

The bus interfaces differ as well. The MI355X uses PCIe 5.0 x16, while the B200 SXM6 uses PCIe 6.0 x16. Both are single modules, but the MI355X is an OAM module and the B200 is an SXM module. Neither card has power connectors recorded as user-serviceable; the MI355X lists none, and the B200 has no data. The suggested power supplies differ by 400 W, with the MI355X requiring 1800 W and the B200 requiring 1400 W.

FAQ

Q: Which accelerator has higher FP32 throughput?

A: The AMD Instinct MI355X delivers 78.64 TFLOPS in FP32, which is 13.4 percent higher than the 69.34 TFLOPS recorded for the NVIDIA B200 SXM6.

Q: How do the memory capacities compare?

A: The MI355X has 288 GB of HBM3e memory, while the B200 SXM6 has 180 GB. Both use an 8192 bit bus and achieve 8.19 TB/s bandwidth.

Q: Which chip has more transistors?

A: The NVIDIA B200 SXM6 has 208,000 million transistors, which is 12.4 percent more than the 185,000 million on the AMD MI355X.

Q: Is there a difference in texture processing capability?

A: Yes. The MI355X records 2,457.6 GTexel/s, which is 126.8 percent higher than the 1,083.4 GTexel/s on the B200 SXM6.

Q: What are the power requirements?

A: The MI355X is rated at 1400 W with a suggested PSU of 1800 W. The B200 SXM6 is rated at 1000 W with a suggested PSU of 1400 W.

Q: Do these cards support display outputs or graphics APIs?

A: Neither card has display outputs. Both record N/A for DirectX, OpenGL, and Vulkan support.

Specification Differences

The process nodes differ: the MI355X uses 3 nm, the B200 SXM6 uses 5 nm, both from TSMC. Die size differs by 752 mm², with the MI355X at 2380 mm² and the B200 at 1628 mm². Transistor counts are 185,000 million for the MI355X and 208,000 million for the B200. Transistor density is 77.7M per mm² for the MI355X and 127.8M per mm² for the B200.

Base clocks are 1000 MHz for the MI355X and 120 MHz for the B200. Boost clocks are 2400 MHz and 1830 MHz respectively. Memory size is 288 GB versus 180 GB. Shading units number 16,384 on the MI355X and 18,944 on the B200. Texture mapping units are 1,024 versus 592. Raster output units are 0 on the MI355X and 24 on the B200. Tensor cores are not recorded on the MI355X, while the B200 has 592.

Pixel rate is 0 MPixel/s on the MI355X and 43.92 GPixel/s on the B200. Texture rate is 2,457.6 GTexel/s versus 1,083.4 GTexel/s. FP32 and FP16 are both 78.64 TFLOPS on the MI355X and 69.34 TFLOPS on the B200. TDP is 1400 W versus 1000 W. Slot width is OAM Module for the MI355X and SXM Module for the B200. Power connectors are listed as none on the MI355X and not recorded on the B200. Suggested PSU is 1800 W versus 1400 W. Bus interface is PCIe 5.0 x16 on the MI355X and PCIe 6.0 x16 on the B200.

Dimensions are recorded only for the MI355X: 102 mm length and 165 mm width. The B200 has no recorded dimensions. Production status is not recorded for the MI355X and is Active for the B200. Release dates are 2025-06-11 for the MI355X and 2024-10-31 for the B200. The predecessor is Radeon Instinct for the MI355X and Server Hopper for the B200. The B200 has a successor, Server Rubin, while the MI355X has none recorded. The B200 has a launch MSRP of 34,999 USD; the MI355X has no recorded MSRP.

The Verdict

The recorded data draws a clear line between two different acceleration strategies. The AMD Instinct MI355X leads in raw floating-point throughput, texture rate, memory capacity, and boost clock. Its 78.64 TFLOPS in FP32 and FP16 puts it ahead of the B200 SXM6 by 13.4 percent, and its 2,457.6 GTexel/s texture rate is more than double the NVIDIA part. The 288 GB memory capacity is a 60 percent advantage over the 180 GB on the B200. These numbers position the MI355X for workloads that scale with shader throughput, texture work, and large in-memory datasets.

The NVIDIA B200 SXM6 counters with higher shading unit count, tensor cores, pixel output, transistor density, and a more mature production status. Its 18,944 shading units exceed the MI355X by 15.6 percent, and its 592 tensor cores provide a hardware path for matrix operations that the MI355X does not record. The 43.92 GPixel/s pixel rate confirms that the B200 implements a full raster pipeline, while the MI355X records zero pixel output. The B200 also consumes 400 W less power, which lowers the suggested PSU requirement from 1800 W to 1400 W.

The transistor data favors NVIDIA on density, but AMD on die area. The B200 fits 12.4 percent more transistors into a die that is 31.6 percent smaller, which explains its higher density figure. The MI355X uses a larger, higher-power design to reach its performance numbers. Both parts share identical memory bandwidth at 8.19 TB/s and the same HBM3e memory type, so memory speed is not a differentiator.

The release timeline favors the B200, which is Active in production and was released on 2024-10-31. The MI355X has a later release date of 2025-06-11 and no recorded production status. The B200 also has a successor planned in Server Rubin, while the MI355X has none listed. Neither card offers display outputs or graphics APIs, which marks both as pure compute accelerators.

For workloads that depend on FP32 and FP16 throughput, texture rate, or memory capacity, the MI355X is the stronger choice based on the recorded data. For workloads that rely on tensor cores, pixel output, or lower power draw, the B200 SXM6 has the specification advantage. The lack of direct benchmark scores leaves the final performance ranking open, but the architectural data indicates that each card targets a different compute profile. The MI355X maximizes shader and texture throughput on a large die with a high power budget. The B200 SXM6 balances a dense transistor layout with tensor acceleration and a lower thermal footprint.