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AMD Navy Flounder and Sienna Cichlid Specifications Leak in ROCm Update

A sharp-eyed redditor found a listing in the new ROCm (Radeon open compute) firmware update that reveals some of the specs for the highly-anticipated RDNA2 Sienna Cichlid (Big Navi) and Navy Flounder (Navi 22 or 23) graphics cards. Things could change over the next month as AMD fine-tunes its gear, so take these specs with a grain of salt – even though the numbers come from an official firmware update, these specs aren’t confirmed.

The firmware update indicates Sienna Cichlid (Navi 21, i.e., Big Navi) will feature 80 CUs and a 256-bit memory bus. The CU count for this GPU is interesting, indicating all that we know on Big Navi could be legit, with most signs pointing to 80 CUs (or around 80 CUs) to be the spec for Big Navi. If this is true, not to mention if the GPU runs on TSMC’s latest 7nm process, we could see RTX 3080-levels of performance, but with much better efficiency.

Navi GPU Specifications from Linux Kernel Firmware Update:
Parameter Navi 10 Navi 14 Navi 12 Sienna Cichlid (Big Navi) Navy Flounder (Navi 22/23)
gc_num_se 2 1 2 4 2
gc_num_cu_per_sh 10 12 10 10 10
gc_num_sh_per_se 2 2 2 2 2
gc_num_rb_per_se 8 8 8 4 4
gc_num_tccs 16 8 16 16 12
gc_num_gprs 1024 1024 1024 1024 1024
gc_num_max_gs_thds 32 32 32 32 32
gc_gs_table_depth 32 32 32 32 32
gc_gsprim_buff_depth 1792 1792 1792 1792 1792
gc_double_offchip_lds_buffer 1024 512 1024 1024 1024
gc_wave_size 32 32 32 32 32
gc_max_waves_per_simd 20 20 20 16 16
gc_lds_size 64 64 64 64 64
num_sc_per_sh 1 1 1 1 1
num_packer_per_sc 2 2 2 4 4

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