AMD Radeon RX 6500 or RX 6600 GPUs to feature 32 MB Infinity Cache; no bandwidth amplifier capabilities for the Van Gogh architecture
AMD has updated AMDKFD, the Linux kernel Heterogeneous System Architecture (HSA) driver for its APUs. The patch adds L2 and L3 cache information for GPUs, and updates the L1 cache information that was already present. The patch may seem fairly innocuous, but L3 cache appears to refer to Infinity Cache, which RDNA 2 GPUs use as a 'massive bandwidth amplifier'.
Accordingly, AMDKFD describes Sienna Cichlid (Navi 21) as having 128 MB of Infinity Cache, and Navy Flounder (Navi 22) 96 MB. Additionally, the file contains L3 cache information for Dimgrey Cavefish, which is believed to be Navi 23, the GPU that AMD will be using for the RX 6500 or RX 6600 series. AMDKFD states that Dimgrey Cavefish has 32 MB of Infinity Cache, so it should follow that this is how much AMD has allotted for its entry-level RDNA 2 desktop cards.
Moreover, AMDKFD contains references to Van Gogh, a mobile architecture expected to be AMD's first with RDNA-based GPUs. While AMD's iGPUs have outperformed Intel's in recent years, they have done so using the older Vega architecture (5th generation GCN). Van Gogh is expected to feature Zen 2 CPU cores too, so it is unclear how it will slot into AMD's product stack.
However, AMDKFD does not show any L3 cache for Van Gogh. It remains to be seen what AMD will use Van Gogh for, but it looks like it does not possess Infinity Cache. AMDKFD implies that Van Gogh has 8 Compute Units (CUs) too, which is the same volume as the Radeon RX Vega 8 (Ryzen 4000) has.
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