AMD Radeon Instinct MI25 vs AMD Radeon RX 6950 XT Comparison

# AMD Radeon Instinct MI25 vs AMD Radeon RX 6950 XT

The AMD Radeon Instinct MI25 and AMD Radeon RX 6950 XT represent two very different eras and purposes within AMD's product stack. The MI25, a GCN 5.0 compute accelerator from 2017, targets data-center workloads with its HBM2 memory and lack of display outputs. The RX 6950 XT, built on RDNA 2.0 and released in 2022, is a gaming flagship with ray tracing hardware and a full suite of display outputs. The benchmark data shows a decisive performance gap, but the architectural story is more nuanced than a single score suggests.

FAQ

Q: Which card has the higher average benchmark score?

A: The AMD Radeon RX 6950 XT has an average benchmark score of 58,392, while the AMD Radeon Instinct MI25 scores 68,562 in its single Geekbench OpenCL test. However, the MI25's average is based on one test, whereas the RX 6950 XT's average spans eleven benchmarks including DirectX, Metal, Vulkan, and PassMark tests.

Q: How do the two cards compare in the Geekbench OpenCL test?

A: The RX 6950 XT scores 205,998 versus the MI25's 68,562, representing a 66.7% advantage for the RX 6950 XT. This is the only head-to-head benchmark available between the two.

Q: What is the percentile ranking of each card among all GPUs?

A: The MI25 sits at the 90th percentile, while the RX 6950 XT ranks at the 88th percentile. Despite the RX 6950 XT's much higher raw scores in individual tests, its average is dragged down by lower scores in some PassMark tests.

Q: Which card has more shading units?

A: The RX 6950 XT has 5,120 shading units compared to 4,096 on the MI25. The RX 6950 XT also has more texture mapping units (320 versus 256) and more render output units (128 versus 64).

Q: What are the closest rivals for each card?

A: The MI25's nearest rival is the Intel Arc A770, which scores 68,809, a 0.4% difference. The RX 6950 XT's nearest rival is the NVIDIA P102-100, scoring 58,528, just 0.2% behind.

Q: Do both cards support the same DirectX version?

A: No. The MI25 supports DirectX 12 (12_1), while the RX 6950 XT supports DirectX 12 Ultimate (12_2). The RX 6950 XT also supports Vulkan 1.4, while the MI25 supports Vulkan 1.3.

Architecture Differences

The two cards are built on fundamentally different architectures and manufacturing processes. The MI25 uses the Vega 10 chip based on GCN 5.0 architecture, fabricated on a 14 nm process at GlobalFoundries. The RX 6950 XT uses the Navi 21 chip based on RDNA 2.0, fabricated on a 7 nm process at TSMC. This process shrink from 14 nm to 7 nm is a major factor in the performance difference.

The transistor counts reflect this generational leap. The MI25 packs 12,500 million transistors on a 495 mm² die, yielding a transistor density of 25.3 million per square millimeter. The RX 6950 XT crams 26,800 million transistors onto a 520 mm² die, achieving 51.5 million per square millimeter. The RX 6950 XT has more than double the transistor density, fitting over twice as many transistors into a similar physical footprint.

Memory architecture diverges sharply. The MI25 uses 16 GB of HBM2 on a 2048-bit bus, delivering 436.2 GB/s of bandwidth. The RX 6950 XT also has 16 GB of memory, but uses GDDR6 on a 256-bit bus, achieving 576.0 GB/s. The RX 6950 XT has 32% more bandwidth despite a bus width that is one-eighth the size, thanks to much higher effective memory clocks (18 Gbps versus 1704 Mbps).

The compute configurations differ substantially. The MI25 has 4,096 shading units, 256 TMUs, and 64 ROPs. The RX 6950 XT has 5,120 shading units, 320 TMUs, and 128 ROPs. Critically, the RX 6950 XT adds 80 ray tracing cores, which the MI25 lacks entirely. Clock speeds also favor the RX 6950 XT, with a base clock of 1860 MHz and boost of 2310 MHz versus the MI25's 1400 MHz base and 1500 MHz boost.

The MI25 is a compute-focused accelerator with no display outputs, while the RX 6950 XT includes 1x HDMI 2.1 and 2x DisplayPort 1.4a outputs. The MI25 uses PCIe 3.0 x16, and the RX 6950 XT uses PCIe 4.0 x16.

Head-to-Head Benchmarks

The only direct benchmark comparison available is the Geekbench OpenCL test. In this test, the RX 6950 XT scores 205,998 against the MI25's 68,562, a delta of 66.7% in favor of the RX 6950 XT. This is a substantial margin, indicating the RX 6950 XT delivers roughly three times the OpenCL compute performance of the MI25.

The MI25's single benchmark score of 68,562 places it at the 90th percentile among all GPUs. Its nearest rivals include the Intel Arc A770 (68,809, 0.4% behind), NVIDIA CMP 90HX (69,000, 0.6% behind), AMD Radeon Pro WX 8200 (69,870, 1.9% behind), and NVIDIA Quadro P6000 (69,986, 2% behind). This clustering suggests the MI25 is competitive with a broad range of professional and consumer cards from its era, but the gap to the RX 6950 XT is enormous.

The RX 6950 XT's benchmark portfolio is much broader. Its Geekbench Vulkan score is 165,212, and its Geekbench Metal score is 222,653. The PassMark tests show significant variance: it scores 28,070 in G3D, 14,199 in GPU Compute, 1,063 in G2D, and lower scores in the DirectX-specific tests (164 in DirectX 10, 300 in DirectX 11, 114 in DirectX 12, 303 in DirectX 9). The 3DMark Steel Nomad DX12 score is 4,235.

The RX 6950 XT's average benchmark score of 58,392 is lower than the MI25's 68,562, but this is misleading because the averages are computed over different test sets. The RX 6950 XT's nearest rivals include the NVIDIA P102-100 (58,528, 0.2% ahead), Intel Arc A570M (58,239, 0.3% behind), AMD Radeon PRO V710 (58,657, 0.5% ahead), and AMD Radeon RX 5600 OEM (58,085, 0.5% behind).

Specification Differences

The two cards differ in nearly every measurable specification. The MI25 uses a 14 nm process from GlobalFoundries, while the RX 6950 XT uses a 7 nm process from TSMC. Transistor counts are 12,500 million versus 26,800 million, and die sizes are 495 mm² versus 520 mm². Transistor density is 25.3M per mm² versus 51.5M per mm².

Clock speeds: the MI25 runs at 1400 MHz base and 1500 MHz boost, while the RX 6950 XT runs at 1860 MHz base and 2310 MHz boost. The RX 6950 XT also has a game clock of 2100 MHz. Memory clocks are 852 MHz (1704 Mbps effective) for the MI25 versus 2250 MHz (18 Gbps effective) for the RX 6950 XT.

Memory configuration: both have 16 GB, but the MI25 uses HBM2 on a 2048-bit bus with 436.2 GB/s bandwidth, while the RX 6950 XT uses GDDR6 on a 256-bit bus with 576.0 GB/s bandwidth. The MI25 has 4,096 shading units, 256 TMUs, and 64 ROPs. The RX 6950 XT has 5,120 shading units, 320 TMUs, and 128 ROPs, plus 80 ray tracing cores.

Fill rates and compute throughput: the MI25 achieves 96.00 GPixel/s pixel rate and 384.0 GTexel/s texture rate, with 12.29 TFLOPS FP32 and 24.58 TFLOPS FP16. The RX 6950 XT achieves 295.7 GPixel/s and 739.2 GTexel/s, with 23.65 TFLOPS FP32 and 47.31 TFLOPS FP16. The RX 6950 XT roughly doubles the MI25's compute throughput.

Power and physical specs: the MI25 has a 300 W TDP, while the RX 6950 XT has a 335 W TDP. Both use 2x 8-pin power connectors and recommend a 700 W PSU. The MI25 is dual-slot, while the RX 6950 XT is triple-slot. Both are 267 mm long, but the RX 6950 XT is taller (120 mm versus 111 mm) and has defined width (50 mm versus none listed). The MI25 has no display outputs; the RX 6950 XT has 1x HDMI 2.1 and 2x DisplayPort 1.4a. The MI25 uses PCIe 3.0 x16; the RX 6950 XT uses PCIe 4.0 x16.

Where Each One Wins

The RX 6950 XT wins decisively in raw compute performance. Its Geekbench OpenCL score is 66.7% higher than the MI25's, and its FP32 throughput of 23.65 TFLOPS versus 12.29 TFLOPS represents a 92% advantage. The RX 6950 XT also has higher texture rate (739.2 GTexel/s versus 384.0 GTexel/s) and pixel rate (295.7 GPixel/s versus 96.00 GPixel/s). For gaming, the RX 6950 XT's ray tracing cores, DirectX 12 Ultimate support, and display outputs make it the clear choice. Its 576.0 GB/s memory bandwidth and 18 Gbps effective memory clock are also superior.

The MI25 wins in a few specific areas. Its 90th percentile ranking is higher than the RX 6950 XT's 88th percentile, though this reflects the different benchmark sets. The MI25's average benchmark score of 68,562 is higher than the RX 6950 XT's 58,392, again due to test composition. The MI25 has a lower TDP (300 W versus 335 W) and a smaller physical footprint (dual-slot versus triple-slot). Its HBM2 memory on a 2048-bit bus may offer advantages in certain compute workloads that benefit from wide memory interfaces, though the RX 6950 XT's higher bandwidth suggests this is not a practical advantage.

For compute-focused applications where OpenCL performance is the primary metric, the RX 6950 XT's 66.7% lead in Geekbench OpenCL is the dominant factor. The MI25's lack of display outputs and older GCN 5.0 architecture limit its relevance outside of specific data-center workloads.

The Verdict

The data points to a clear winner: the AMD Radeon RX 6950 XT outperforms the AMD Radeon Instinct MI25 by a wide margin in the available benchmark. The 66.7% delta in Geekbench OpenCL, combined with roughly double the FP32 and FP16 throughput, makes the RX 6950 XT the superior choice for most workloads. Its 7 nm process, 5,120 shading units, 80 ray tracing cores, and 576.0 GB/s memory bandwidth represent a generational leap over the MI25's 14 nm GCN 5.0 design.

The MI25's higher percentile ranking (90 versus 88) and higher average benchmark score (68,562 versus 58,392) are artifacts of its limited benchmark portfolio, not evidence of superior performance. When directly compared on the same test, the RX 6950 XT dominates.

Who should pick the MI25? Users with legacy compute workloads specifically optimized for GCN 5.0 and HBM2 memory, or those requiring a lower-power dual-slot accelerator with no display outputs for headless servers, might find it adequate. Its 436.2 GB/s bandwidth and 12.29 TFLOPS FP32 are still respectable for certain data-center tasks.

Who should pick the RX 6950 XT? Anyone needing maximum compute performance, gaming capability, or modern API support. The RX 6950 XT's DirectX 12 Ultimate, Vulkan 1.4, ray tracing cores, and display outputs make it a versatile card for both gaming and compute. Its 23.65 TFLOPS FP32 performance is nearly double the MI25's, and its 47.31 TFLOPS FP16 throughput is similarly dominant. For any user choosing between these two cards based on the benchmark data, the RX 6950 XT is the rational selection.