AMD Instinct MI355X vs AMD Radeon RX 9070 XT Comparison

FAQ

Q: What is the architectural generation of each GPU?

A: The AMD Instinct MI355X uses the CDNA 4.0 architecture on the MI350 256CU chip, while the AMD Radeon RX 9070 XT uses RDNA 4.0 on the Navi 48 chip. The MI355X belongs to the Instinct (MIx) generation, and the RX 9070 XT belongs to the Navi IV (RX 9000) generation.

Q: How do the process nodes and transistor counts compare?

A: The MI355X is built on a 3 nm process at TSMC with 185,000 million transistors on a 2380 mm² die. The RX 9070 XT uses a 4 nm process at TSMC with 53,900 million transistors on a 357 mm² die. The MI355X has a transistor density of 77.7M per mm², while the RX 9070 XT has a higher density of 151.0M per mm².

Q: What are the memory configurations of the two cards?

A: The MI355X carries 288 GB of HBM3e memory on an 8192-bit bus with 8.19 TB/s bandwidth. The RX 9070 XT has 16 GB of GDDR6 memory on a 256-bit bus with 644.6 GB/s bandwidth.

Q: Which card has higher FP32 compute throughput?

A: The MI355X delivers 78.64 TFLOPS FP32, compared to 48.66 TFLOPS for the RX 9070 XT. Both cards achieve a 1:1 ratio for FP16, meaning each card's FP16 figure equals its FP32 figure.

Q: What is the average benchmark score for the RX 9070 XT?

A: The RX 9070 XT has an average benchmark score of 13543 across recorded tests, placing it in the 55th percentile of all GPUs in the database. The MI355X has no recorded benchmark scores and sits at the 50th percentile.

Q: What are the power requirements for each card?

A: The MI355X has a TDP of 1400 W with a suggested PSU of 1800 W, and it uses an OAM Module slot width with no power connectors. The RX 9070 XT has a TDP of 304 W with a suggested PSU of 700 W and uses 2x 8-pin power connectors.

Architecture Differences

The MI355X and RX 9070 XT represent two divergent AMD architectures. The MI355X is a compute accelerator built on CDNA 4.0, optimized for dense numerical workloads. The RX 9070 XT is a graphics card using RDNA 4.0, designed for rendering and real-time graphics. The MI355X uses the MI350 256CU chip, while the RX 9070 XT uses the Navi 48 chip.

The process node difference is notable: the MI355X uses TSMC's 3 nm process, while the RX 9070 XT uses TSMC's 4 nm process. The MI355X packs 185,000 million transistors into a 2380 mm² die, a massive area that supports its HBM3e memory stack. The RX 9070 XT integrates 53,900 million transistors into 357 mm², achieving a higher transistor density of 151.0M per mm² versus 77.7M per mm² for the MI355X.

Compute resources differ sharply. The MI355X has 16384 shading units and 1024 texture mapping units, with no ROPs reported. The RX 9070 XT has 4096 shading units, 256 TMUs, and 128 ROPs. The MI355X also lists no RT cores, while the RX 9070 XT includes 64 RT cores. The MI355X's texture rate is 2,457.6 GTexel/s, far above the RX 9070 XT's 760.3 GTexel/s, and its pixel rate is listed as 0 MPixel/s versus 380.2 GPixel/s for the RX 9070 XT.

Memory architecture is a fundamental split. The MI355X uses HBM3e with 288 GB capacity, an 8192-bit bus, and 8.19 TB/s bandwidth. The RX 9070 XT uses GDDR6 with 16 GB capacity, a 256-bit bus, and 644.6 GB/s bandwidth. Clock behavior also differs: the MI355X has a base of 1000 MHz and boost of 2400 MHz, while the RX 9070 XT has a base of 1660 MHz, boost of 2970 MHz, and a game clock of 2400 MHz. The memory clocks are 2000 MHz (8 Gbps effective) for the MI355X and 2518 MHz (20.1 Gbps effective) for the RX 9070 XT.

API support separates the two. The MI355X reports no DirectX, OpenGL, or Vulkan support. The RX 9070 XT supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. Display outputs also differ: the MI355X has no outputs, while the RX 9070 XT provides 1x HDMI 2.1b and 3x DisplayPort 2.1a.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark entries between the MI355X and RX 9070 XT. The MI355X has no benchmark scores recorded, so its average benchmark score is zero. The RX 9070 XT, however, has ten recorded benchmark results across multiple suites.

In 3DMark Steel Nomad DX12, the RX 9070 XT scores 7260. In Geekbench OpenCL, it scores 17428, and in Geekbench Vulkan, it scores 65879. PassMark results for the RX 9070 XT include DirectX 10 at 154, DirectX 11 at 292, DirectX 12 at 78, DirectX 9 at 353, G2D at 1328, G3D at 26795, and GPU Compute at 15864.

The RX 9070 XT's average benchmark score of 13543 places it in the 55th percentile of all GPUs. Its nearest rivals in the database are the AMD Radeon HD 7770M with an average score of 13536 and a delta of 0.1%, the NVIDIA GeForce GTX 570 at 13515 with a delta of 0.2%, the NVIDIA P106-090 at 13470 with a delta of 0.5%, and the AMD Radeon Pro 555 at 13407 with a delta of 1%. These deltas are extremely tight, indicating the RX 9070 XT's average score sits within 1% of these older or lower-tier cards.

Because the MI355X lacks any benchmark entries, no direct comparison of measured performance is possible from the recorded data. The MI355X's percentile of 50 is a neutral placeholder, not a measured result. The compute specifications, such as 78.64 TFLOPS FP32 for the MI355X versus 48.66 TFLOPS for the RX 9070 XT, suggest a theoretical advantage for the MI355X in raw throughput, but no benchmark confirms this.

Specification Differences

The two cards differ across nearly every specification category. The MI355X uses the MI350 256CU chip with CDNA 4.0, while the RX 9070 XT uses the Navi 48 chip with RDNA 4.0. Process nodes are 3 nm for the MI355X and 4 nm for the RX 9070 XT. Transistor counts are 185,000 million versus 53,900 million, and die sizes are 2380 mm² versus 357 mm².

Clock speeds: the MI355X has a base of 1000 MHz and boost of 2400 MHz, while the RX 9070 XT has a base of 1660 MHz, boost of 2970 MHz, and a game clock of 2400 MHz. Memory clocks are 2000 MHz (8 Gbps effective) for the MI355X and 2518 MHz (20.1 Gbps effective) for the RX 9070 XT.

Memory: the MI355X has 288 GB of HBM3e on an 8192-bit bus with 8.19 TB/s bandwidth. The RX 9070 XT has 16 GB of GDDR6 on a 256-bit bus with 644.6 GB/s bandwidth.

Compute units: the MI355X has 16384 shading units and 1024 TMUs, with ROPs listed as 0. The RX 9070 XT has 4096 shading units, 256 TMUs, and 128 ROPs. The MI355X has no RT cores listed, while the RX 9070 XT has 64. Pixel rates are 0 MPixel/s for the MI355X and 380.2 GPixel/s for the RX 9070 XT. Texture rates are 2,457.6 GTexel/s and 760.3 GTexel/s, respectively.

FP32 and FP16 are both 78.64 TFLOPS for the MI355X and 48.66 TFLOPS for the RX 9070 XT, with both maintaining a 1:1 FP16 ratio.

Power: the MI355X has a TDP of 1400 W and suggested PSU of 1800 W, with no power connectors and an OAM Module slot width. The RX 9070 XT has a TDP of 304 W and suggested PSU of 700 W, with 2x 8-pin connectors and a Dual-slot design.

Bus interface is PCIe 5.0 x16 for both. Display outputs: the MI355X has none, while the RX 9070 XT has 1x HDMI 2.1b and 3x DisplayPort 2.1a. APIs: the MI355X has N/A for DirectX, OpenGL, and Vulkan, while the RX 9070 XT supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Dimensions: the MI355X is 102 mm (4 inches) long and 165 mm (6.5 inches) wide, with no height listed. The RX 9070 XT has no dimensions recorded.

Release dates differ: the MI355X launched on 2025-06-11, and the RX 9070 XT launched on 2025-03-05. The RX 9070 XT has a launch MSRP of 599 USD. The MI355X has no launch MSRP recorded.

Where Each One Wins

The MI355X wins on raw compute capacity. Its FP32 throughput of 78.64 TFLOPS is 61.7% higher than the RX 9070 XT's 48.66 TFLOPS. Its texture rate of 2,457.6 GTexel/s is more than three times the RX 9070 XT's 760.3 GTexel/s. Memory bandwidth is dramatically higher: 8.19 TB/s versus 644.6 GB/s, a difference of over 12 times. Memory capacity is 288 GB versus 16 GB. The MI355X also uses a newer 3 nm process versus 4 nm, and it has a larger transistor count of 185,000 million versus 53,900 million.

The RX 9070 XT wins on graphics-specific features. It has 128 ROPs and 64 RT cores, enabling pixel rendering and ray tracing, while the MI355X has zero ROPs and no RT cores. The RX 9070 XT supports modern graphics APIs including DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI355X supports none. Display outputs are present on the RX 9070 XT (1x HDMI 2.1b, 3x DisplayPort 2.1a), absent on the MI355X. The RX 9070 XT also has a higher boost clock of 2970 MHz versus 2400 MHz, and a higher base clock of 1660 MHz versus 1000 MHz.

The RX 9070 XT has measured benchmark data, with an average score of 13543 and a 55th percentile standing. The MI355X has no benchmarks recorded, so its actual performance in any workload cannot be confirmed from the database.

Power efficiency favors the RX 9070 XT. Its TDP of 304 W is far lower than the MI355X's 1400 W. The suggested PSU is 700 W for the RX 9070 XT versus 1800 W for the MI355X. The RX 9070 XT also uses standard 2x 8-pin power connectors and a Dual-slot design, while the MI355X is an OAM Module with no connectors.

The Verdict

The data indicates two entirely different products with minimal overlap. The MI355X is a compute accelerator with enormous memory capacity, bandwidth, and FP32 throughput, but it lacks any graphics output, ROPs, or API support. Its 288 GB HBM3e memory and 8.19 TB/s bandwidth suit workloads that require massive data movement, and its 78.64 TFLOPS FP32 positions it for dense compute tasks. The absence of benchmark scores means its practical performance is unknown from the database, but its specifications place it in a compute-oriented category.

The RX 9070 XT is a graphics card with measured benchmark results. Its average score of 13543 and 55th percentile ranking come from real tests, including 3DMark Steel Nomad DX12 at 7260, Geekbench Vulkan at 65879, and PassMark G3D at 26795. It supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, and it provides display outputs. Its 16 GB GDDR6 memory and 644.6 GB/s bandwidth are conventional for a graphics card, and its 304 W TDP is manageable with a 700 W PSU.

A user needing compute acceleration, massive memory capacity, or extreme bandwidth would look at the MI355X, based on its memory and throughput specifications. A user needing a graphics card with rendering, ray tracing, and API support would use the RX 9070 XT, based on its ROPs, RT cores, API list, and benchmark scores. The MI355X has no recorded wins in benchmarks, and the RX 9070 XT has no recorded losses, but the comparison is limited by the MI355X's lack of test data.

The MI355X's launch date of 2025-06-11 and the RX 9070 XT's launch date of 2025-03-05 indicate the RX 9070 XT entered the market earlier. The RX 9070 XT has a production status of Active, while the MI355X has no production status recorded. The MI355X's predecessor is Radeon Instinct, and the RX 9070 XT's predecessor is Navi III. Neither has a successor listed.

The data does not support a direct performance ranking between the two. The MI355X offers superior raw specifications for compute, and the RX 9070 XT offers superior graphics functionality and verified benchmark performance. Each card wins in its own domain, and the selection depends on whether the workload is compute-oriented or graphics-oriented. The MI355X's higher FP32 and memory bandwidth make it the choice for compute-heavy tasks, while the RX 9070 XT's API support, display outputs, and benchmark scores make it the choice for graphics workloads.