AMD Radeon Instinct MI25 vs NVIDIA GeForce RTX 4090 Comparison

The AMD Radeon Instinct MI25 and NVIDIA GeForce RTX 4090 are separated by five years, two process nodes, and a fundamental shift in GPU design philosophy. The benchmark data is unambiguous: the RTX 4090 dominates the sole head-to-head test, delivering a Geekbench OpenCL score of 255,416 against the MI25’s 68,562, a 73.2% advantage for NVIDIA. However, the MI25 is not without merit; its 90th percentile ranking among all GPUs, versus the RTX 4090’s 88th, indicates that in specific legacy compute workloads, the older AMD card remains competitive relative to its peers. The data shows a clear generational leap, but also a nuanced picture where architectural strengths and weaknesses dictate use cases beyond raw speed.

Where Each One Wins

The NVIDIA GeForce RTX 4090 wins the only direct benchmark comparison, and it wins decisively. In Geekbench OpenCL, the RTX 4090 scores 255,416 versus the MI25’s 68,562, a 73.2% lead. This single result suggests the RTX 4090 is the superior choice for any modern, OpenCL-based compute task, from machine learning inference to video processing. Its performance percentile of 88, while slightly lower than the MI25’s 90, is misleading; the RTX 4090 sits in a far more crowded and faster field, making its raw score all the more impressive.

The AMD Radeon Instinct MI25, despite losing the head-to-head, has a story to tell. Its 90th percentile ranking indicates that in the broader GPU landscape, it outperforms a significant majority of all other cards. This is particularly relevant for legacy applications or specific compute workloads that are optimized for GCN architecture. The MI25’s nearest rivals—the Intel Arc A770 (0.4% behind), NVIDIA CMP 90HX (0.6% behind), and AMD Radeon Pro WX 8200 (1.9% behind)—are all modern or prosumer cards, yet the MI25 holds its own within 2% of each. For a 2017 product, that speaks to a durable compute design that still finds relevance in niche deployments.

Where the RTX 4090 wins is in sheer throughput and modern feature support. It offers 82.58 TFLOPS FP32 and FP16 performance, a 1:1 ratio that eliminates the MI25’s 2:1 penalty for FP16 work. The RTX 4090 also brings dedicated ray tracing and tensor cores—128 and 512, respectively—which are absent from the MI25 entirely. For any workload leveraging these accelerators, the RTX 4090 is not just faster; it is in a different category. Conversely, the MI25 wins on power efficiency per compute unit in legacy scenarios, though the data does not provide a direct wattage comparison beyond TDP figures of 300W versus 450W.

Architecture Differences

The architectural gulf between these two GPUs is vast. The AMD Radeon Instinct MI25 is built on the Vega 10 chip using GCN 5.0 architecture, fabricated on a 14 nm process at GlobalFoundries. It packs 12,500 million transistors on a 495 mm² die, yielding a transistor density of 25.3 million per mm². The NVIDIA GeForce RTX 4090, by contrast, uses the AD102 chip with Ada Lovelace architecture, built on a 5 nm process at TSMC. It contains 76,300 million transistors on a 609 mm² die, achieving a density of 125.3 million per mm²—a 4.95x improvement in transistor packing.

Memory systems diverge sharply. The MI25 uses 16 GB of HBM2 on a 2048-bit bus, delivering 436.2 GB/s of bandwidth. The RTX 4090 uses 24 GB of GDDR6X on a 384-bit bus, achieving 1.01 TB/s. While the RTX 4090 has a narrower bus, its faster memory technology and larger capacity provide more than double the bandwidth. The MI25’s HBM2 is a legacy choice, but its 2048-bit interface was designed for high-bandwidth compute; the RTX 4090’s GDDR6X achieves superior throughput with a simpler layout.

Compute resources differ by an order of magnitude. The MI25 has 4,096 shading units, 256 texture mapping units, and 64 ROPs. The RTX 4090 has 16,384 shading units, 512 TMUs, and 176 ROPs—4x, 2x, and 2.75x more, respectively. The RTX 4090 also introduces 128 RT cores and 512 tensor cores, neither of which exist on the MI25. Pixel and texture rates reflect this: the RTX 4090 hits 443.5 GPixel/s and 1,290.2 GTexel/s, versus the MI25’s 96.0 GPixel/s and 384.0 GTexel/s. Clock speeds also favor NVIDIA, with a base of 2235 MHz and boost of 2520 MHz against the MI25’s 1400 MHz base and 1500 MHz boost.

Head-to-Head Benchmarks

The only direct benchmark comparison in the data is Geekbench OpenCL. Here, the NVIDIA GeForce RTX 4090 scores 255,416, while the AMD Radeon Instinct MI25 scores 68,562. The deltaPct is -73.2% for the MI25, meaning it trails by nearly three-quarters. This is not a marginal win; it is a generational obliteration. The RTX 4090’s score is more than 3.7x higher, a gap that cannot be bridged by driver optimizations or workload tuning.

Contextualizing this result: the MI25’s nearest rivals in the broader database are the Intel Arc A770 (68,809, a 0.4% difference) and the NVIDIA CMP 90HX (69,000, a 0.6% difference). The RTX 4090’s nearest rivals are the Intel Arc Pro A60 (60,326, a 0% difference) and the AMD Radeon Pro Vega 48 (60,140, a 0.3% difference). This reveals that the MI25’s score is typical for its class, while the RTX 4090’s score is far above its immediate peers—yet its percentile is lower, suggesting that many other high-end GPUs score even higher. The RTX 4090’s other benchmarks, such as PassMark G3D (38,194) and Geekbench Vulkan (271,631), are not directly comparable to the MI25, but they reinforce its compute leadership.

The RTX 4090 also wins on feature-specific tests, though no head-to-head data exists for those. Its PassMark GPU Compute score of 26,613 and 3DMark Steel Nomad DX12 score of 9,223 indicate strong modern API performance. The MI25 has no equivalent data, so any comparison there would be speculative. The single head-to-head result stands as the definitive measure: the RTX 4090 is the winner.

FAQ

Q: Which GPU has a higher Geekbench OpenCL score?

A: The NVIDIA GeForce RTX 4090 scores 255,416, while the AMD Radeon Instinct MI25 scores 68,562. The RTX 4090 leads by 73.2%.

Q: Does the AMD Radeon Instinct MI25 support ray tracing or tensor cores?

A: No. The MI25 has no RT cores and no tensor cores. The NVIDIA GeForce RTX 4090 includes 128 RT cores and 512 tensor cores.

Q: What is the memory bandwidth difference between the two cards?

A: The MI25 offers 436.2 GB/s of bandwidth via HBM2 on a 2048-bit bus. The RTX 4090 offers 1.01 TB/s via GDDR6X on a 384-bit bus, which is more than double.

Q: How do their transistor densities compare?

A: The MI25 has 25.3 million transistors per mm² on a 14 nm process. The RTX 4090 has 125.3 million per mm² on a 5 nm process, a nearly 5x density advantage.

Q: Which GPU has a higher percentile ranking among all GPUs?

A: The MI25 ranks at the 90th percentile, while the RTX 4090 ranks at the 88th percentile. Despite a lower percentile, the RTX 4090’s absolute scores are far higher.

Q: Are both GPUs end-of-life products?

A: Yes. The MI25 was released in June 2017 and is end-of-life. The RTX 4090 was released in September 2022 and is also end-of-life, with a successor in the GeForce 50 series.

Specification Differences

The following specifications differ between the AMD Radeon Instinct MI25 and the NVIDIA GeForce RTX 4090:

• Process Node: MI25 is 14 nm (GlobalFoundries); RTX 4090 is 5 nm (TSMC).
• Transistors: MI25 has 12,500 million; RTX 4090 has 76,300 million.
• Die Size: MI25 is 495 mm²; RTX 4090 is 609 mm².
• Transistor Density: MI25 is 25.3M / mm²; RTX 4090 is 125.3M / mm².
• Base Clock: MI25 is 1400 MHz; RTX 4090 is 2235 MHz.
• Boost Clock: MI25 is 1500 MHz; RTX 4090 is 2520 MHz.
• Memory Size: MI25 is 16 GB; RTX 4090 is 24 GB.
• Memory Type: MI25 is HBM2; RTX 4090 is GDDR6X.
• Memory Bus: MI25 is 2048-bit; RTX 4090 is 384-bit.
• Memory Bandwidth: MI25 is 436.2 GB/s; RTX 4090 is 1.01 TB/s.
• Shading Units: MI25 has 4,096; RTX 4090 has 16,384.
• TMUs: MI25 has 256; RTX 4090 has 512.
• ROPs: MI25 has 64; RTX 4090 has 176.
• RT Cores: MI25 has none; RTX 4090 has 128.
• Tensor Cores: MI25 has none; RTX 4090 has 512.
• Pixel Rate: MI25 is 96.00 GPixel/s; RTX 4090 is 443.5 GPixel/s.
• Texture Rate: MI25 is 384.0 GTexel/s; RTX 4090 is 1,290.2 GTexel/s.
• FP32 Performance: MI25 is 12.29 TFLOPS; RTX 4090 is 82.58 TFLOPS.
• FP16 Performance: MI25 is 24.58 TFLOPS (2:1); RTX 4090 is 82.58 TFLOPS (1:1).
• TDP: MI25 is 300 W; RTX 4090 is 450 W.
• Slot Width: MI25 is dual-slot; RTX 4090 is triple-slot.
• Power Connectors: MI25 uses 2x 8-pin; RTX 4090 uses 1x 16-pin.
• Suggested PSU: MI25 is 700 W; RTX 4090 is 850 W.
• Bus Interface: MI25 is PCIe 3.0 x16; RTX 4090 is PCIe 4.0 x16.
• Display Outputs: MI25 has no outputs; RTX 4090 has 1x HDMI 2.13x DisplayPort 1.4a.
• DirectX Support: MI25 is 12 (12_1); RTX 4090 is 12 Ultimate (12_2).
• Vulkan Support: MI25 is 1.3; RTX 4090 is 1.4.
• Dimensions: MI25 is 267 mm (10.5 inches) long and 111 mm (4.4 inches) high; RTX 4090 is 304 mm (12 inches) long, 137 mm (5.4 inches) high, and 61 mm (2.4 inches) wide.

The Verdict

The data points to one clear conclusion: for any modern compute workload, the NVIDIA GeForce RTX 4090 is the superior product. Its 73.2% lead in Geekbench OpenCL is the only direct comparison, but that margin is supported by its architectural advantages—4x the shading units, 2.3x the memory bandwidth, and dedicated RT/tensor cores. The RTX 4090 also offers a 1:1 FP16 ratio, meaning no performance penalty for half-precision work, and its 82.58 TFLOPS FP32 output is nearly 7x the MI25’s. For users running AI inference, ray tracing, or high-throughput compute, the RTX 4090 is the only rational choice, despite its higher TDP of 450W and triple-slot footprint.

The AMD Radeon Instinct MI25 is not obsolete, but its use case is narrow. Its 90th percentile ranking suggests it still outperforms most GPUs in existence, and its 16 GB of HBM2 with a 2048-bit bus provides respectable bandwidth for legacy compute tasks. Its nearest rivals—all within 2% in average score—include modern cards like the Intel Arc A770, indicating that the MI25’s GCN architecture remains optimized for certain OpenCL workloads. For users with existing GCN-specific codebases or those operating in constrained power envelopes (300W TDP), the MI25 remains viable. However, its lack of RT/tensor cores, lower clock speeds, and older PCIe 3.0 interface are insurmountable for future-proofing.

The verdict is clear: the RTX 4090 wins on every measurable metric that matters today. The MI25’s only advantage is its higher percentile ranking, which is a statistical artifact of competing in a less challenging field. If the task is modern, the RTX 4090 is the answer. If the task is legacy and GCN-optimized, the MI25 still works—but the data cannot justify choosing it over the RTX 4090 in a fresh deployment. The RTX 4090’s launch MSRP was 1,599 USD, and for that price, it delivers a performance class that the MI25, at any price, cannot approach.