AMD Navi 22 Navy Flounder RDNA 2 GPU With 40 CUs, 2560 Cores & 192-bit Memory Bus Spotted

AMD’s Navi 22 “Navy Flounder” GPU has been spotted in the latest ROCm 3.8 update, revealing the specifications of the chip that would go on to power the Radeon RX 6800 or RX 6700 series graphics cards.

The Navy Flounder GPU isn’t a new name and has been known around the same time we got to hear about Sienna Chiclid. As per the leaks, AMD’s Navi 21 GPU which is also referred to as AMD Big Navi GPU goes by the Sienna Chiclid codename whereas the Navi 22 GPU is a cut-down GPU which is internally codenamed as Navy Flounder.

As per the details spotted by Reddit user, Stlbr (via Videocardz & TUM_APISAK), it looks like we now know what the Navi 22 GPU has to offer in terms of specifications. As per the details, AMD’s Navy Flounder or Navi 22 GPU is expected to feature 40 Compute Units. If AMD keeps the same stream processor count on its RDNA 2 generation of GPUs as the RDNA 1 lineup (which is 64 stream processors per CU), we get 2560 cores in total for the Navi 22 GPU.

 

 

This would get us the same core count as the Radeon RX 5700 XT. In addition to the core count, the GPU is suggested to feature a 192-bit bus interface which is something we have heard on multiple occasions in the last few weeks. As per the rumor mill, the Navi 21 GPUs (Radeon RX 6900 series) is expected to feature a 256-bit bus interface with up to 16 GB GDDR6 memory while the Navi 22 GPU (Radeon RX 6800/6700 series) is expected to feature a 192-bit bus interface with up to 12 GB VRAM.

AMD Navi GPUs Comparison:

Parameter Navi 10 Navi 14 Navi 12 Sienna Cichlid (Navi 21?) Navy Flounder (Navi 22?)
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

There are interesting things to consider with the listed patch as it mentions Navy Flounder GPUs so we can expect several SKUs of the Navi 22 chip and not just one particular configuration which is a common practice by GPU manufacturers. The chip falls in the GFX10.3 architecture generation that is commonly referred to as the GFX103X series for RDNA 2 chips. The Navi 21 GPU is based on the GFX1030 while the Navi 23 GPU is based on the GFX1032 graphics architecture. So one will assume that the Navi 22 GPU will be based on the GFX1031 graphics architecture.

Some major design changes for the Navi 22 ‘Navy Flounder’ GPU are also reported compared to Navi 21 ‘Sienna Cichlid’ GPU. The use of VCN 3.0 (Video Core Next) and DCN 3.0 (Display Core Next) reaffirm that this is an RDNA 2 GPU but there’s supporting evidence that Navi 22 is a lower-tier chip compared to Navi 21. For starters, the Navi 22 GPU only features one instance of VC3 vs two on Navi 21. Also, the SDMA controllers have dropped to two compared to four on the Navi 21 GPU.

Previous rumors have also suggested a die size of around 340mm2 for the Navi 22 GPU but that’s purely speculation at this point. We still have no real details and actual specifications for AMD’s RDNA 2 consumer desktop graphics cards. The expected die sizes of these three GPUs are also listed below:

  • AMD Navi 21 (505mm2)
  • AMD Navi 22 (340mm2)
  • AMD Navi 23 (240mm2)

AMD will officially be unveiling its Radeon RX 6000 series graphics card family on October 28th. The second half of 2020 would definitely be interesting times for all the hardware enthusiasts and mainstream PC gamers who are looking forward to upgrading their PCs with the best hardware.

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