AMD Instinct MI355X vs NVIDIA GeForce RTX 5080 Comparison

Where Each One Wins

The recorded data splits these two accelerators across entirely different workloads, and the split is not close. The AMD Instinct MI355X is an OAM module with no display outputs and no graphics API support. The database shows its benchmark suite is empty, meaning there are no recorded DirectX, OpenGL, or Vulkan results for the MI355X. Its percentile versus all GPUs sits at 50, with an average benchmark score of 0. This positions it outside the consumer graphics testing methodology entirely.

The NVIDIA GeForce RTX 5080, by contrast, has a full benchmark profile. It records an average benchmark score of 56,083 and sits at the 87th percentile versus all GPUs. Its benchmark results span DirectX 9, 10, 11, and 12, OpenCL, Vulkan, compute, and 2D workloads. The RTX 5080 clearly wins every recorded benchmark in the database, simply because the MI355X has no entries. The MI355X wins in categories the RTX 5080 does not target: memory capacity, memory bandwidth, shading unit count, texture unit count, and raw FP32 throughput. The RTX 5080 wins in every graphics API test, every rasterization test, and all measured gaming-oriented workloads. For compute-specific tasks, the RTX 5080 has a recorded PassMark GPU compute score of 21,789, while the MI355X has no comparable entry. The data indicates that a system builder choosing between these two must decide between a compute-oriented accelerator with no graphics pipeline and a graphics card with a full API stack and measured display output support.

Architecture Differences

The two chips come from different foundries and different process nodes. The MI355X uses a 3 nm process at TSMC, while the RTX 5080 uses a 5 nm process at TSMC. The MI355X carries 185,000 million transistors on a 2380 mm² die, giving a transistor density of 77.7 million per mm². The RTX 5080 carries 45,600 million transistors on a 378 mm² die, for a density of 120.6 million per mm². Despite the smaller node, the MI355X has a lower transistor density because its die is exceptionally large and dominated by memory and compute arrays.

The MI355X uses the CDNA 4.0 architecture on the MI350 256CU chip, part of the Instinct (MIx) generation. The RTX 5080 uses the Blackwell 2.0 architecture on the GB203 chip, part of the GeForce 50 series. The MI355X has 16,384 shading units, 1,024 texture mapping units, and 0 ROPs. Its pixel rate is recorded as 0 MPixel/s. The RTX 5080 has 10,752 shading units, 336 TMUs, and 112 ROPs, with a pixel rate of 293.1 GPixel/s. The MI355X has no RT cores and no tensor cores listed in the database, while the RTX 5080 includes 84 RT cores and 336 tensor cores.

The MI355X supports no DirectX, OpenGL, or Vulkan APIs. The RTX 5080 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. The MI355X has no display outputs and uses a PCIe 5.0 x16 bus interface. The RTX 5080 also uses PCIe 5.0 x16, but includes 1x HDMI 2.1b and 3x DisplayPort 2.1b outputs. The MI355X is an OAM Module with a 1400 W TDP and no power connectors, requiring a suggested 1800 W power supply. The RTX 5080 is a dual-slot card with a 360 W TDP, a single 16-pin connector, and a suggested 750 W power supply. The MI355X measures 102 mm in length and 165 mm in width. The RTX 5080 measures 304 mm in length, 137 mm in height, and 40 mm in width.

Head-to-Head Benchmarks

Direct comparison is limited because the MI355X has no benchmark scores in the database. The nearest rivals listed for the RTX 5080 provide context for its performance tier. The RTX 5080's average score of 56,083 is 0.6% above the AMD Radeon 8060S (55,757), 0.7% above the AMD Radeon RX 6750 GRE 12 GB (55,698), and 2.3% above the AMD Radeon Pro W5700X (54,828). The AMD Radeon RX 9070 GRE scores 57,367, which is 2.2% higher than the RTX 5080.

Within its own benchmark suite, the RTX 5080 shows a varied profile. Its highest raw score is in Geekbench Vulkan at 255,450, followed by Geekbench OpenCL at 235,901. Its PassMark G3D score is 36,565, and its PassMark GPU compute score is 21,789. The DirectX results are lower in absolute terms: PassMark DirectX 12 scores 151, DirectX 11 scores 324, DirectX 10 scores 208, and DirectX 9 scores 389. The PassMark G2D score is 1,415. The 3DMark Steel Nomad DX12 score is 8,637.

These numbers show the RTX 5080's compute-oriented APIs (OpenCL and Vulkan) deliver substantially higher scores than its legacy DirectX tests. The MI355X, with no recorded benchmarks, cannot be compared on any of these tests directly. The database does indicate the MI355X's FP32 throughput at 78.64 TFLOPS, which is 39.7% higher than the RTX 5080's 56.28 TFLOPS. The MI355X also records FP16 at 78.64 TFLOPS (1:1), identical to its FP32 rate. The RTX 5080 also records FP16 at 56.28 TFLOPS (1:1). The texture rate of the MI355X is 2,457.6 GTexel/s versus 879.3 GTexel/s for the RTX 5080. The MI355X's memory bandwidth is 8.19 TB/s from 288 GB of HBM3e on an 8192-bit bus. The RTX 5080 has 960.0 GB/s from 16 GB of GDDR7 on a 256-bit bus. The MI355X delivers 8.5 times the memory bandwidth of the RTX 5080, a gap that matters for large data movement workloads.

FAQ

Q: Which GPU has better raw FP32 compute throughput?

A: The AMD Instinct MI355X records 78.64 TFLOPS FP32, while the NVIDIA GeForce RTX 5080 records 56.28 TFLOPS FP32. The MI355X is 39.7% higher in this metric.

Q: Does the AMD Instinct MI355X support DirectX or Vulkan?

A: No. The database lists the MI355X's DirectX, OpenGL, and Vulkan APIs as N/A. The RTX 5080 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4.

Q: How does the RTX 5080 compare to its nearest rivals in average benchmark score?

A: The RTX 5080 averages 56,083. It is 0.6% above the AMD Radeon 8060S, 0.7% above the AMD Radeon RX 6750 GRE 12 GB, 2.3% above the AMD Radeon Pro W5700X, and 2.2% below the AMD Radeon RX 9070 GRE.

Q: What memory configurations do the two cards use?

A: The MI355X uses 288 GB of HBM3e on an 8192-bit bus with 8.19 TB/s bandwidth. The RTX 5080 uses 16 GB of GDDR7 on a 256-bit bus with 960.0 GB/s bandwidth.

Q: What are the power requirements for each card?

A: The MI355X has a 1400 W TDP and a suggested power supply of 1800 W. The RTX 5080 has a 360 W TDP and a suggested power supply of 750 W.

Q: Does the MI355X have any display outputs?

A: No. The MI355X lists "No outputs" in its display outputs field. The RTX 5080 includes 1x HDMI 2.1b and 3x DisplayPort 2.1b.

Specification Differences

The two accelerators differ in nearly every recorded specification field. The MI355X uses a 3 nm process node, the RTX 5080 a 5 nm node, both at TSMC. Transistor count is 185,000 million versus 45,600 million. Die size is 2380 mm² versus 378 mm². Transistor density is 77.7 million per mm² versus 120.6 million per mm². The MI355X has a base clock of 1000 MHz and boost of 2400 MHz. The RTX 5080 has a base clock of 2295 MHz and boost of 2617 MHz. Memory clock differs: 2000 MHz (8 Gbps effective) for the MI355X versus 1875 MHz (30 Gbps effective) for the RTX 5080.

Memory capacity is 288 GB versus 16 GB. Memory type is HBM3e versus GDDR7. Bus width is 8192 bit versus 256 bit. Bandwidth is 8.19 TB/s versus 960.0 GB/s. Shading units are 16,384 versus 10,752. TMUs are 1,024 versus 336. ROPs are 0 versus 112. The MI355X lists no RT cores or tensor cores; the RTX 5080 has 84 RT cores and 336 tensor cores. Pixel rate is 0 MPixel/s versus 293.1 GPixel/s. Texture rate is 2,457.6 GTexel/s versus 879.3 GTexel/s. FP32 is 78.64 TFLOPS versus 56.28 TFLOPS. FP16 is 78.64 TFLOPS (1:1) versus 56.28 TFLOPS (1:1). TDP is 1400 W versus 360 W.

Slot width is OAM Module versus dual-slot. Power connectors are none versus 1x 16-pin. Suggested PSU is 1800 W versus 750 W. Display outputs are none versus 1x HDMI 2.1b and 3x DisplayPort 2.1b. The MI355X has no graphics API support; the RTX 5080 supports DirectX 12 Ultimate (12_2), OpenGL 4.6, and Vulkan 1.4. Dimensions differ: the MI355X is 102 mm long and 165 mm wide, while the RTX 5080 is 304 mm long, 137 mm high, and 40 mm wide. The MI355X has no launch MSRP recorded. The RTX 5080 has a launch MSRP of 999 USD. The MI355X released on June 11, 2025, while the RTX 5080 released on January 29, 2025. The MI355X's predecessor is Radeon Instinct; the RTX 5080's predecessor is GeForce 40 and its successor is GeForce 60.