AMD (via Kepler_L2) released a new Linux patch that exposes the cache configuration for its Navi 21, Navi 22 and Navi 23 silicon. The last is rumored to power the chipmaker's upcoming Radeon RX 6600 series (or maybe RX 6500 series).
The description for the patch reads: "The L1 cache information has been updated and the L2/L3 information has been added. The changes have been made for Vega10 and newer ASICs. There are no changes for the older ASICs before Vega10." Therefore, it holds a ton of valuable information on both existing and future AMD products.
Introduced with RDNA 2, Infinity Cache basically acts as a big L3 cache that's accessible by the GPU. It's there to help improve performance since AMD's RDNA 2 graphics cards employ relatively narrow memory interfaces. The Radeon RX 6800 XT for example uses a 256-bit bus, but manages to mostly keep pace with the GeForce RTX 3080's 320-bit bus that also includes higher clocked GDDR6X memory.
Navi 21 (Sienna Cichlid) and Navi 22 (Navy Flounder) sport 128MB and 96MB of Infinity Cache, respectively. According to the new information, Navi 23 will wield 32MB of Infinity Cache. In comparison to Navi 22, we're looking at a 66.7% reduction on Navi 23. That should also help cut down the die size, though at the cost of performance.
The jury is still out on whether AMD will use Navi 23 for the Radeon RX 6600 series, though. Some think that Navi 23 could find its way into the Radeon RX 6500 series instead. Regardless, AIDA64, a popular monitoring and diagnostics tool, recently received support for Radeon RX 6600 series. Assuming that the software's release notes are accurate, the Radeon RX 6600 XT and RX 6600 will indeed be based around the Navi 23 die.
ASRock registered a couple of Radeon RX 6600 XT models with the Eurasian Economic Commission (EEC) not so long ago. It's important to highlight that not every product makes it to the market, but if what ASRock submitted is true, the Radeon RX 6600 XT may feature 12GB of GDDR6 memory. Realistically, it makes more sense for the Radeon RX 6600 XT to have 8GB of GDDR6 memory across a 128-bit memory interface.
The fact that AIDA64 already supports the Radeon RX 6600 series hints that a potential launch may not be too far around the corner. We're still waiting for a trimmed down Radeon RX 6700 using Navi 22, which we expect to see some time in April.