RDNA 2 (Released November 18, 2020) is AMD’s breakthrough GPU microarchitecture, powering the Radeon RX 6000 series and next-gen consoles (PlayStation 5, Xbox Series X/S, Steam Deck).

It marked AMD’s return to high-end GPU competitiveness with significant innovations in efficiency, caching, and feature support 128. Below is a detailed analysis of its key aspects:

⚙️ 1. Architectural Innovations

Compute Units (CUs) and Workgroup Processors (WGPs)

• Enhanced CU Design: Each RDNA 2 CU contains 64 shader cores, with up to 80 CUs in flagship dies (e.g., Navi 21). This doubled the CU count from RDNA 1’s max of 40 CUs 16.
• WGP Organization: Two CUs form a WGP, sharing 32 KB L0 cache (16 KB vector + 16 KB scalar). WGPs operate in two modes:
  • WGP Mode: Unified 128 KB Local Data Store (LDS).
  • CU Mode: Split 64 KB LDS halves for finer task handling 5.
• Efficiency Gains: RDNA 2 achieved 54% higher performance-per-watt vs. RDNA 1, with 21% attributed to Infinity Cache and 30% to clock-speed optimizations 16.

Infinity Cache

• Purpose: A global L3 cache (16–128 MB) designed to reduce reliance on GDDR6 memory bandwidth. It allowed AMD to use a narrower 256-bit bus instead of power-hungry 512-bit designs 168.
• Performance:
  • 128 MB cache (Navi 21) delivered 56% hit rates at 4K, reducing latency by 34% vs. RDNA 1 6.
  • Peak bandwidth of 1,986.6 GB/s, enabling effective bandwidth 2.17× higher than raw GDDR6 specs 18.
  • Lower-tier GPUs (e.g., Navi 23: 32 MB; Navi 22: 96 MB) scaled cache size for cost efficiency 8.

🚀 2. Key Technologies

Ray Tracing

• Ray Accelerators: Dedicated units per CU handling 4 ray/box intersections or 1 ray/triangle intersection per clock. Accessed via DirectX Raytracing (DXR) or VulkanRT 18.
• Performance: Initially lagged behind Nvidia’s Ampere but gained up to 40% improvement via driver updates in 2023 18.

Clock Speeds and Power Efficiency

• Frequency Boost: RDNA 2 GPUs hit >2.1 GHz (e.g., RX 6800 XT: 2,250 MHz boost), a 30% increase over RDNA 1 at same power 168.
• Optimizations: Fine-grain clock gating, redesigned data paths, and CPU-GPU collaboration on TSMC’s 7 nm process 6.

Media Engine

• VCN 3.x Block: Added AV1 decoding (up to 8K) but omitted encoding until RDNA 3. Lower-end dies (Navi 24) lack media encoders entirely 18.

💻 3. Product Lineup and Specifications

RDNA 2 GPUs spanned four dies, targeting desktop, mobile, and workstation markets:

Desktop GPUs (Select Models)

*Post-2023 price cuts reduced MSRPs by 5–30% (e.g., RX 6900 XT: $699) 9.*

Console Integration

• PlayStation 5 / Xbox Series X|S: Custom RDNA 2 APUs with 36 CUs (PS5) and 52 CUs (Xbox Series X), optimized for console-specific memory and cooling 18.

⚖️ 4. Competitive Analysis

• vs. Nvidia Ampere:
  • Strengths: Higher rasterization performance at 1440p (thanks to Infinity Cache), lower VRAM latency, and aggressive pricing 68.
  • Weaknesses: Ray tracing and AI (e.g., DLSS) lagged behind Ampere 8.
• Efficiency: Matched Nvidia in power efficiency despite using GDDR6 (vs. power-hungry GDDR6X) 8.

🌍 5. Impact and Legacy

• Market Position: Restored AMD’s competitiveness in high-end GPUs after a decade of trailing Nvidia 68.
• Developer Ecosystem: Supported DirectX 12 Ultimate (ray tracing, mesh shaders) and AMD’s FidelityFX tools, enhancing game optimization 2.
• Successor: RDNA 3 (2022) built on this foundation with chiplet design and >50% perf-per-watt gains