https://www.techpowerup.com/299089/icymi-nvidia-geforce-rtx-4080-12gb-uses-192-bit-memory-bus Amid the fog of rapid announcements and AIC graphics card launches, this little, interesting detail might have missed you, but the new GeForce RTX 4080 12 GB graphics card announced yesterday; features a memory bus-width of just 192-bit, which is half that of the RTX 3080 12 GB (384-bit). The card uses 21 Gbps GDDR6X memory, which at 192-bit bus-width, works out to just 504 GB/s bandwidth. In comparison, the RTX 3080 12 GB uses 19 Gbps GDDR6X memory, which at 384-bit bus width, produces 912 GB/s. In fact, even the original RTX 3080 with 10 GB of GDDR6X memory across a 320-bit bus, has 760 GB/s on tap.
The bigger RTX 4080 16 GB variant uses 256-bit memory bus, but faster 23 Gbps GDDR6X memory, producing 736 GB/s of memory bandwidth, which again, is less than that of the original 10 GB RTX 3080. It's only the RTX 4090 that has an unchanged amount of memory bandwidth over the previous generation—1008 GB/s, which is identical to that of the RTX 3090 Ti, and a tad higher than the 936 GB/s of the RTX 3090 (non-Ti). Of course, memory bandwidth is no way to compare the RTX 40-series from its predecessors, there are a dozen other factors that weigh into performance, and what matters is you're getting generationally more memory amounts with the RTX 4080-series. The RTX 4080 12 GB offers 20% more memory than the RTX 3080, and the RTX 4080 16 GB offers 33% more than the RTX 3080 12 GB. NVIDIA tends to deliver significant performance gains with each new generation, and we expect this to hold up.
Although the memory bus is lower performance will be much higher.
