AMD Radeon Instinct MI25 vs AMD Radeon RX 6800 XT Comparison

FAQ

Q: Which GPU has the higher average benchmark score?

A: The AMD Radeon RX 6800 XT has a significantly higher average benchmark score at 48,477, while the AMD Radeon Instinct MI25 records an average of 68,562. Interestingly, the MI25's average comes from a single OpenCL test, whereas the RX 6800 XT's average is derived from multiple benchmark suites.

Q: How do the two cards compare in the shared OpenCL benchmark?

A: In the Geekbench OpenCL test, the RX 6800 XT scores 171,304 compared to the MI25's 68,562. The RX 6800 XT wins this head-to-head with a delta of -60%, meaning the MI25 trails by 60 percentage points in this specific test.

Q: What are the percentile rankings for each GPU in the database?

A: The MI25 sits at the 90th percentile among all GPUs, while the RX 6800 XT ranks at the 85th percentile. Despite the RX 6800 XT's lower percentile, its raw average score is higher due to the distribution of scores across the database.

Q: Which GPU has more shading units?

A: The RX 6800 XT has 4,608 shading units, whereas the MI25 has 4,096. This represents a difference of 512 shading units in favor of the newer RDNA 2.0 card.

Q: What is the memory configuration difference between the two?

A: Both cards have 16 GB of memory, but the MI25 uses HBM2 with a 2048-bit bus and 436.2 GB/s bandwidth, while the RX 6800 XT uses GDDR6 with a 256-bit bus and 512.0 GB/s bandwidth. The RX 6800 XT has higher total bandwidth despite the narrower bus.

Q: Which GPU supports ray tracing hardware?

A: Only the RX 6800 XT includes 72 dedicated ray tracing cores. The MI25, based on GCN 5.0, does not list any RT cores in its specifications.

Architecture Differences

The two cards represent fundamentally different architectural generations from AMD. The MI25 is built on the Vega 10 chip using GCN 5.0 architecture, manufactured on a 14 nm process at GlobalFoundries. It packs 12,500 million transistors into a 495 mm² die, yielding a transistor density of 25.3 million per square millimeter. In contrast, the RX 6800 XT uses the Navi 21 chip with RDNA 2.0 architecture, fabricated on a 7 nm process by TSMC. This newer chip contains 26,800 million transistors across a 520 mm² die, achieving a density of 51.5 million per square millimeter, more than double the MI25's density.

The memory subsystems differ structurally as well. The MI25 uses HBM2 memory with a very wide 2048-bit bus, while the RX 6800 XT employs GDDR6 on a 256-bit bus. The RX 6800 XT still achieves higher bandwidth at 512.0 GB/s versus 436.2 GB/s for the MI25. Both cards have 16 GB of memory, but the HBM2 implementation on the MI25 is characteristic of data center accelerators, whereas the GDDR6 on the RX 6800 XT is typical of consumer gaming cards.

Feature support also diverges. The RX 6800 XT includes 72 ray tracing cores, a hardware feature entirely absent from the MI25. The DirectX support differs: the MI25 supports DirectX 12 (12_1), while the RX 6800 XT supports DirectX 12 Ultimate (12_2). Vulkan support is also newer on the RX 6800 XT at version 1.4 versus 1.3 on the MI25. Both support OpenGL 4.6.

The clock speeds reflect the architectural maturity of RDNA 2.0. The MI25 has a base clock of 1400 MHz and a boost of 1500 MHz. The RX 6800 XT runs substantially higher with a base of 1825 MHz, a game clock of 2015 MHz, and a boost of 2250 MHz. These higher clocks contribute to the RX 6800 XT's significant performance advantage in raw throughput metrics.

Head-to-Head Benchmarks

The database contains one directly comparable benchmark between these two GPUs: the Geekbench OpenCL test. In this measurement, the RX 6800 XT scores 171,304 while the MI25 scores 68,562. The delta is -60%, meaning the MI25 delivers only 40% of the RX 6800 XT's performance in this workload. This is a substantial margin that places the two cards in entirely different performance tiers for compute tasks.

Beyond the shared test, the RX 6800 XT has additional benchmark data that the MI25 lacks. In Geekbench Metal, the RX 6800 XT scores 181,337, and in Geekbench Vulkan it records 136,875. These results indicate strong cross-API performance, though no direct comparison to the MI25 is possible since the MI25 has no recorded scores for those tests.

The MI25's average score of 68,562 places it near several rivals in the database. The Intel Arc A770 scores 68,809, just 0.4% higher. The NVIDIA CMP 90HX scores 69,000, 0.6% above. The AMD Radeon Pro WX 8200 scores 69,870, 1.9% higher, and the NVIDIA Quadro P6000 scores 69,986, 2% higher. These tight margins show the MI25 sitting at the edge of a cluster of similar-performance cards.

The RX 6800 XT's average score of 48,477 is actually lower than its individual Geekbench OpenCL result, because the average includes scores from Passmark tests that are on different scales. Its nearest rivals include the NVIDIA RTX A1000 Mobile at 47,743 (1.5% lower), the Intel Arc A550M at 49,737 (2.5% higher), the NVIDIA GeForce RTX 5070 Ti at 49,957 (3% higher), and the AMD Radeon RX Vega 64 at 50,001 (3% higher). The RX 6800 XT sits in a tight competitive band with these cards.

Specification Differences

The process node differs: the MI25 uses 14 nm from GlobalFoundries, while the RX 6800 XT uses 7 nm from TSMC. Transistor counts are 12,500 million for the MI25 and 26,800 million for the RX 6800 XT. Die size is 495 mm² versus 520 mm², and transistor density is 25.3M per mm² versus 51.5M per mm².

Clock speeds differ across all measured points. The MI25 has a base of 1400 MHz and boost of 1500 MHz with no game clock listed. The RX 6800 XT has a base of 1825 MHz, a game clock of 2015 MHz, and a boost of 2250 MHz. Memory clocks also differ: the MI25 runs at 852 MHz with 1704 Mbps effective, while the RX 6800 XT runs at 2000 MHz with 16 Gbps effective.

Memory type and bus width differ: HBM2 with 2048-bit on the MI25 versus GDDR6 with 256-bit on the RX 6800 XT. Bandwidth favors the RX 6800 XT at 512.0 GB/s versus 436.2 GB/s. The MI25 has 4,096 shading units, 256 TMUs, and 64 ROPs. The RX 6800 XT has 4,608 shading units, 288 TMUs, and 128 ROPs. The RX 6800 XT also adds 72 RT cores.

Pixel and texture rates favor the RX 6800 XT heavily: 288.0 GPixel/s versus 96.00 GPixel/s, and 648.0 GTexel/s versus 384.0 GTexel/s. FP32 performance is 20.74 TFLOPS for the RX 6800 XT versus 12.29 TFLOPS for the MI25. FP16 performance is 41.47 TFLOPS versus 24.58 TFLOPS.

The bus interface differs: PCIe 3.0 x16 on the MI25 versus PCIe 4.0 x16 on the RX 6800 XT. Display outputs are absent on the MI25, while the RX 6800 XT has 1x HDMI 2.1, 2x DisplayPort 1.4a, and 1x USB Type-C. Dimensions are similar in length (267 mm) but differ in height: 111 mm for the MI25 versus 120 mm for the RX 6800 XT. The RX 6800 XT also has a listed width of 50 mm.

Where Each One Wins

The RX 6800 XT wins the only shared benchmark decisively, with a 60% delta advantage in Geekbench OpenCL. This single data point suggests the RX 6800 XT is considerably stronger in raw compute throughput. Its higher clock speeds, more shading units, and doubled ROP count all contribute to this outcome.

The RX 6800 XT also shows advantages in specifications that translate to real-world performance. Its FP32 throughput of 20.74 TFLOPS exceeds the MI25's 12.29 TFLOPS by a wide margin. The texture rate of 648.0 GTexel/s versus 384.0 GTexel/s indicates faster texture processing, and the pixel rate of 288.0 GPixel/s versus 96.00 GPixel/s suggests faster rasterization.

The MI25's strengths lie in its memory architecture. The 2048-bit HBM2 bus is four times wider than the RX 6800 XT's 256-bit GDDR6 bus, which can be advantageous in certain bandwidth-sensitive workloads that benefit from high parallelism across many memory channels. However, the total bandwidth is still lower at 436.2 GB/s versus 512.0 GB/s.

The MI25 also holds a slight advantage in its percentile ranking at 90th versus 85th for the RX 6800 XT. This indicates that relative to the entire database, the MI25 sits higher than the RX 6800 XT, though the RX 6800 XT's higher absolute average score complicates this picture.

For display output, the RX 6800 XT is the clear winner with HDMI 2.1, DisplayPort 1.4a, and USB Type-C outputs. The MI25 has no display outputs, making it unsuitable for direct monitor connection.

The Verdict

The data clearly favors the RX 6800 XT for most use cases. Its Geekbench OpenCL score of 171,304 versus 68,562 for the MI25 shows a 60% performance gap that is difficult to overcome. The RX 6800 XT's higher clock speeds, more shading units, doubled ROPs, and ray tracing support make it the more capable card for modern workloads.

The MI25, however, remains competitive in its own niche. Its 90th percentile ranking and proximity to cards like the Intel Arc A770 and NVIDIA CMP 90HX suggest it holds its own among its closest peers. The HBM2 memory with a 2048-bit bus offers a different memory architecture that may suit specific data center workloads where wide buses are preferred.

For gaming and general consumer use, the RX 6800 XT is the obvious choice. It has display outputs, ray tracing hardware, DirectX 12 Ultimate support, and higher raw performance across every measured metric. Its FP32 and FP16 throughput are both roughly 1.7 times higher than the MI25's.

For compute-focused deployments where display output is unnecessary, the MI25 still offers 16 GB of HBM2 memory and a 90th percentile standing. Its end-of-life production status and older GCN architecture, however, limit its appeal compared to the RX 6800 XT's RDNA 2.0 design.

The RX 6800 XT's average score of 48,477 across multiple benchmarks, including Passmark and Geekbench variants, demonstrates versatility. The MI25's single benchmark result of 68,562 provides less context but shows it can compete with a cluster of cards scoring around 68,000 to 70,000.

Users requiring modern API support, ray tracing, and display connectivity should choose the RX 6800 XT. Users prioritizing a wide memory bus and higher database percentile, and who do not need display outputs, may find the MI25 sufficient, though the performance gap in compute workloads is substantial.