Two RTX 4070s
Before we get to the RTX 4080, 2 different variants for the RTX 4070 were spotted a while back. You can read more about it here. Long story short, NVIDIA has been planning to use a 160-bit bus, however, many leakers have contradicted these claims and now we ‘un-officially’ consider the 4070 to ship with a 192-bit bus. Similarly, we have 2 specifications based on the ‘4070’ leaks:
4070 (12GB, 192-bit bus, 7680 Cuda Cores, 285W) [Original]4070 (10GB, 192-bit/160-bit bus, 7168 Cuda Cores, 250W) [New]
The Selection Problem
Coming back to the RTX 4080, Zed__Wang on Twitter gave us 2 possible specifications for this SKU.
note：4080 12G has a completely different pcb design from 4080 16G — MEGAsizeGPU (@Zed__Wang) September 5, 2022 The RTX 4080 comes in 2 flavours, one with 12GB and the other 16GB of G6X VRAM. No specification regarding the bus-width has been given, so we’ll consider it to be 256-bits (As per previous leaks). Now, don’t stress over this too much because NVIDIA even with Ampere had 3 different models for the RTX 3080 (10GB, 12GB and 20GB). These two models are a bit different from one another due to the PCB aic used on them.
10GB Variant – 10 layer PCB aic reference design12GB Variant – 12 layer PCB aic reference design
Could this be the RTX 4070
Many believe that the 10GB model for the RTX 4080 (The new one) features either a 256-bit bus or a 192-bit bus (We chose 256-bits as it made the most sense). This is awfully similar to the RTX 4070. However, the RTX 4080 is powered by the AD103 chip whereas the slower AD104 will be used for the -70 series. All in all, 4GB less VRAM is not something to take lightly. This could essentially be the difference between a smooth 60FPS versus a stutter infested <60FPS experience.
