AMD’s Navi GPUs Confirmed to Retain GCN Design
AMD has already started developing drivers for Navi on the Linux platform. The latest bit of code shows Navi to continue the trend of GCN-based GPUs.
Navi is Set to be Based on GCN
Phoronix recently discovered references to Navi while monitoring various Git repositories. The AMDGPU LLVM back-end is now seeing ‘GFX1010’, and with GFX900 being Vega, GFX1010 could only be Navi.
The snippets of code indicating the usage of GCN are as follows.
- EF_AMDGPU_MACH_AMDGCN_LAST =
Phoronix claims Navi support is unlikely to be seen within the upcoming Linux 5.2 Kernel and may be held back until the Linux 5.3 Kernel release. The current release windows for Linux 5.3 stable is the September release. The Linux 5.3 kernel may be the first Linux kernel bringing mainstream Navi support, and assuming Navi releases sometime between May and July, we may not see much support for these GPUs until Linux 5.3 is released. Until then, Linux users may be required to jump through some hoops to get their shiny new Navi GPUs working properly.
We had previously seen Navi being referred to as a post-GCN design, meaning it could potentially bypass the 4096 SP limit of GCN, but this is not the case. In the past, claims have been made that the GCN architecture would require significant tweaks to allow for additional SPs, to the point where a completely new architecture would have increased appeal. GCN had been designed while 28nm was the cutting edge, and has not been tailored to take advantage of the benefits of 7nm.
GCN is a memory starved design as well, requiring the use of expensive HBM for performance gains, though it has been reported that Navi will take advantage of GDDR6. This can be seen when comparing the Radeon RX Vega 64 and Radeon VII. Both GPUs are based on the Vega architecture, with the Radeon VII clocked slightly higher, but with over double the memory bandwidth.
Navi Release Date
Currently, rumors are pointing at a possible revealing at Computex, followed by the full launch with Ryzen 3000 on 7/7, in reference to 7nm.
What Comes Next? Arcturus
At this point in time, we do not know a whole lot about AMD’s next-generation Arcturus microarchitecture, but what we do know is GPU naming schemes will be returning in a simpler, familiar form, similar to the way Fiji referred to R9 Fury GPUs and Hawaii referred to R9 290 GPUs. Arcturus is believed to be based upon 7nm+.
Alleged AMD Radeon RX 3000 Series Specifications
|Graphics Card||GPU||Compute Units||VRAM||TDP||Performance Class
|RX 3090 XT||Navi 20||64||-||225W||Radeon VII + 10%||$500 US|
|RX 3090||Navi 20||60||-||180W||~Radeon VII||$430 US|
|RX 3080 XT||Navi 10||56||-||190W||~RTX 2070||$330 US|
|RX 3080||Navi 10||52||8GB GDDR6||175W||Vega 64 +10%||$280 US|
|RX 3070 XT||Navi 10||48||-||160W||Vega 64||$250 US|
|RX 3070||Navi 12||40||8GB GDDR6||130W||Vega 56||$200 US|
|RX 3060||Navi 12||32||4GB GDDR6||75W||RX 580||$140 US|