Evaluating the Infinity Cache in AMD Strix Halo
16 hours ago
- #GPU Performance
- #Infinity Cache
- #AMD
- AMD Strix Halo is a high-end mobile chip combining 16 Zen 5 cores and a 20 RDNA 3.5 WGPs GPU.
- Strix Halo uses a 256-bit LPDDR5X-8000 setup with 32 MB Infinity Cache to manage GPU bandwidth demands.
- Infinity Cache, introduced in RDNA2, helps reduce DRAM bandwidth needs but was hard to evaluate until Strix Halo.
- Strix Halo's accessible performance monitoring tools allow analysis of Infinity Cache's effectiveness in graphics workloads.
- Performance monitoring involves comparing traffic at Coherent Stations (CS) and Unified Memory Controllers (UMC) to estimate cache hits.
- Results show Infinity Cache captures ~73% of memory traffic, keeping DRAM bandwidth demands below theoretical limits.
- Higher resolutions reduce Infinity Cache hit rates but bandwidth demands remain manageable across tested workloads.
- AMD's 32 MB cache and 256 GB/s DRAM bandwidth balance performance well for Strix Halo's target use cases.
- Infinity Cache's behavior aligns with AMD's data, showing larger caches and higher bandwidth benefit high-resolution workloads.
- The article calls for AMD to provide direct Infinity Cache hit rate data in developer tools for better optimization.