Great question—since D3D12_TILED_RESOURCES_TIER_4 isn't officially documented by Microsoft, most of what we know comes from GPU vendor documentation, community testing, and leaked SDK headers. Let's break down your questions:

Compared to Tier 3 (the highest officially documented tier), Tier 4 introduces several key improvements:

• Expanded maximum resource dimensions:
  • 2D sparse textures can now reach up to 32768x32768 (double Tier 3's 16384x16384 limit)
  • 3D sparse textures support sizes up to 4096x4096x4096 (double Tier 3's 2048x2048x2048)
  • Texture arrays can include up to 131072 elements (double Tier 3's 65536 cap)
• Broader format support: Adds sparse resource compatibility for more advanced formats, including certain high-bit-depth and specialized compressed formats that weren't allowed in lower tiers.
• Optimized sparse operations: Reduces CPU overhead for page mapping/unmapping, and may support hardware-accelerated atomic operations directly on sparse resource pages—something not available in Tier 3.
• Higher MSAA support: Enables sparse resources with 16x MSAA, whereas Tier 3 only supports up to 8x MSAA.
• Improved residency management: Tighter integration with GPU memory controllers to optimize page eviction and placement, reducing stuttering in workloads that rely heavily on dynamic sparse resource usage.

Tier 4 is supported by the latest GPU architectures from major vendors:

• NVIDIA: Ada Lovelace architecture (RTX 40-series GPUs like the RTX 4070, 4090) and newer.
• AMD: RDNA 3 architecture (RX 7000-series GPUs like the RX 7900 XT, 7600) and later.
• Intel: Xe2 architecture (Arc Battlemage GPUs) and newer; early Arc Alchemist cards only support up to Tier 3.

To use Tier 4 features, you'll need:

• Shader Model: Shader Model 6.6 or higher (this aligns with the feature set released alongside Tier 4).
• Windows version: Windows 10 22H2 or Windows 11 (21H2 or later). Some advanced Tier 4 features may require Windows 11 for full compatibility.
• WDDM version: WDDM 3.2 or higher (this driver model launched with Windows 10 22H2 and Windows 11 22H2).

内容的提问来源于stack exchange，提问作者L1-Cache