AMD Instinct MI455X vs NVIDIA RTX 4500 Ada Generation Comparison

AMD Instinct MI455X and NVIDIA RTX 4500 Ada Generation occupy separate corners of the hardware landscape, and the recorded data reflects that divide. The MI455X is an accelerator module with no display outputs, no standard graphics API support, and a power envelope that requires a 2700 W suggested power supply. The RTX 4500 Ada is a dual-slot workstation card with four DisplayPort 1.4a outputs, DirectX 12 Ultimate support, and a 550 W suggested power supply. The database contains benchmark scores for the RTX 4500 Ada, while the MI455X has no recorded benchmark entries, which shapes the analysis that follows.

Where Each One Wins

The MI455X wins in sheer compute scale. Its 32,768 shading units dwarf the RTX 4500 Ada’s 7,680, and its FP32 throughput of 157.3 TFLOPS is roughly four times the RTX 4500 Ada’s 39.63 TFLOPS. The MI455X also holds a massive memory advantage with 432 GB of HBM4 across a 24,576-bit bus, delivering 23.3 TB/s of bandwidth. The RTX 4500 Ada offers 24 GB of GDDR6 on a 192-bit bus with 432.0 GB/s. In texture processing, the MI455X posts 2,457.6 GTexel/s against the RTX 4500 Ada’s 619.2 GTexel/s.

The RTX 4500 Ada wins in practical workstation utility. It has 80 ROPs and a pixel rate of 206.4 GPixel/s, while the MI455X records 0 ROPs and a pixel rate of 0 MPixel/s. The RTX 4500 Ada includes 60 RT cores and 240 tensor cores, features entirely absent from the MI455X’s specification sheet. The RTX 4500 Ada also supports graphics APIs including DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4, while the MI455X lists N/A for all three. The RTX 4500 Ada carries a 97th percentile ranking among all GPUs in the database, with an average benchmark score of 166,094, whereas the MI455X sits at the 50th percentile with an average benchmark score of 0.

Architecture Differences

The MI455X uses the MI450 256CU chip built on CDNA 5.0 architecture, fabricated by TSMC on a 2 nm process. The RTX 4500 Ada uses the AD103 chip on Ada Lovelace architecture, also from TSMC but on a 5 nm process. The MI455X packs 320,000 million transistors on a 2,990 mm² die, giving a transistor density of 107.0M per mm². The RTX 4500 Ada contains 45,900 million transistors on a 379 mm² die, with a higher density of 121.1M per mm².

Clock behavior differs markedly. The MI455X has a base clock of 1000 MHz and a boost clock of 2400 MHz. The RTX 4500 Ada starts higher at 2070 MHz base and reaches 2580 MHz boost. Memory clocks also diverge: the MI455X runs at 1900 MHz with 7.6 Gbps effective, while the RTX 4500 Ada runs at 2250 MHz with 18 Gbps effective. The MI455X uses HBM4 memory, the RTX 4500 Ada uses GDDR6.

The MI455X is an EAM Module with no power connectors and no display outputs. The RTX 4500 Ada is a dual-slot card with no power connectors listed, four DisplayPort 1.4a outputs, and physical dimensions of 245 mm length and 112 mm height. The MI455X uses PCIe 6.0 x16, while the RTX 4500 Ada uses PCIe 4.0 x16. The MI455X lists its predecessor as Radeon Instinct, released 2026-07-22. The RTX 4500 Ada lists its predecessor as Workstation Ampere, its successor as Blackwell PRO W, and its release date as 2023-08-08. Its production status is Active.

Head-to-Head Benchmarks

The database contains no direct head-to-head benchmark results between the MI455X and the RTX 4500 Ada. The wins tally shows 0 for the MI455X and 0 for the RTX 4500 Ada in direct comparison. However, the RTX 4500 Ada has two recorded Geekbench scores: 160,786 in OpenCL and 171,401 in Vulkan. These produce an average benchmark score of 166,094, placing it at the 97th percentile among all GPUs.

The MI455X has no benchmarks listed, an average benchmark score of 0, and a 50th percentile ranking. The nearest rivals for the RTX 4500 Ada provide context for its scores. The NVIDIA RTX A5500 averages 165,217, which is 0.5% behind the RTX 4500 Ada. The AMD Radeon PRO W7800 averages 164,894, 0.7% behind. The AMD Radeon Pro W6900X averages 168,574, which is 1.5% ahead of the RTX 4500 Ada. The NVIDIA A100 PCIe 40 GB averages 162,504, 2.2% behind.

The RTX 4500 Ada’s Vulkan score of 171,401 exceeds its OpenCL score of 160,786 by roughly 6.6%. This indicates the card’s driver and hardware handle both compute interfaces competently, with a slight edge in Vulkan workloads. The MI455X’s lack of recorded benchmark data means no comparable analysis is possible from the database.

FAQ

Q: Which card has more shading units?

A: The AMD Instinct MI455X has 32,768 shading units, while the NVIDIA RTX 4500 Ada Generation has 7,680.

Q: What memory configurations do these cards use?

A: The MI455X uses 432 GB of HBM4 on a 24,576-bit bus with 23.3 TB/s bandwidth. The RTX 4500 Ada uses 24 GB of GDDR6 on a 192-bit bus with 432.0 GB/s bandwidth.

Q: Does the MI455X support graphics APIs?

A: No. The MI455X lists DirectX, OpenGL, and Vulkan as N/A. The RTX 4500 Ada supports DirectX 12 Ultimate, OpenGL 4.6, and Vulkan 1.4.

Q: What is the power requirement difference?

A: The MI455X has a TDP of 2300 W and a suggested power supply of 2700 W. The RTX 4500 Ada has a TDP of 210 W and a suggested power supply of 550 W.

Q: How does the RTX 4500 Ada compare to its nearest rivals?

A: The RTX 4500 Ada averages 166,094. The NVIDIA RTX A5500 is 0.5% behind, the AMD Radeon PRO W7800 is 0.7% behind, the AMD Radeon Pro W6900X is 1.5% ahead, and the NVIDIA A100 PCIe 40 GB is 2.2% behind.

Q: What are the process nodes for each card?

A: The MI455X uses a 2 nm process from TSMC. The RTX 4500 Ada uses a 5 nm process from TSMC.

Specification Differences

The two cards differ across nearly every measurable specification. The MI455X has 32,768 shading units versus 7,680 on the RTX 4500 Ada. Texture mapping units number 1,024 on the MI455X versus 240 on the RTX 4500 Ada. The MI455X has 0 ROPs, while the RTX 4500 Ada has 80. The RTX 4500 Ada has 60 RT cores and 240 tensor cores; the MI455X lists none for both.

FP32 performance is 157.3 TFLOPS on the MI455X and 39.63 TFLOPS on the RTX 4500 Ada. FP16 performance is 157.3 TFLOPS (1:1) on the MI455X and 39.63 TFLOPS (1:1) on the RTX 4500 Ada. Texture rate is 2,457.6 GTexel/s versus 619.2 GTexel/s. Pixel rate is 0 MPixel/s versus 206.4 GPixel/s.

Memory size is 432 GB versus 24 GB. Memory type is HBM4 versus GDDR6. Bus width is 24,576 bit versus 192 bit. Bandwidth is 23.3 TB/s versus 432.0 GB/s. Base clock is 1000 MHz versus 2070 MHz. Boost clock is 2400 MHz versus 2580 MHz. Memory clock is 1900 MHz with 7.6 Gbps effective versus 2250 MHz with 18 Gbps effective.

Transistor count is 320,000 million versus 45,900 million. Die size is 2,990 mm² versus 379 mm². Transistor density is 107.0M per mm² versus 121.1M per mm². Process node is 2 nm versus 5 nm. TDP is 2300 W versus 210 W. Suggested PSU is 2700 W versus 550 W. Slot width is EAM Module versus Dual-slot. Bus interface is PCIe 6.0 x16 versus PCIe 4.0 x16. Display outputs are none versus 4x DisplayPort 1.4a. The RTX 4500 Ada has dimensions of 245 mm length and 112 mm height; the MI455X lists none.

The Verdict

The recorded data points to two distinct intended uses. The MI455X delivers massive raw compute resources: 432 GB of HBM4 memory, 23.3 TB/s bandwidth, and 157.3 TFLOPS of FP32 throughput. It has no display outputs, no graphics API support, and no ROPs, which confirms it is not designed for rendering to a screen. Its 2300 W TDP and 2700 W suggested power supply indicate a server or datacenter installation where power density is not the primary constraint. The RTX 4500 Ada, by contrast, is a workstation card with display outputs, graphics API support, RT cores, and tensor cores, operating within a 210 W TDP and a 550 W suggested power supply.

The RTX 4500 Ada’s benchmark results place it at the 97th percentile among all GPUs, with an average score of 166,094. Its nearest rivals sit within a narrow 2.2% band, showing competitive performance in its class. The MI455X has no benchmark scores in the database, so its real-world performance cannot be quantified here. Its specification sheet indicates a focus on memory capacity and compute throughput rather than graphics features or energy efficiency.

For workloads that require graphics output, API support, or ray tracing, the RTX 4500 Ada is the only option with the necessary hardware. For workloads that prioritize massive memory capacity, extreme bandwidth, and raw FP32 compute, the MI455X provides the larger resource pool. The absence of benchmark data for the MI455X and the presence of two Geekbench scores for the RTX 4500 Ada means the database can confirm the RTX 4500 Ada’s standing among its peers, but cannot offer a measured comparison between these two cards. The specification sheets show a clear split: the MI455X is a compute module, the RTX 4500 Ada is a workstation graphics card.