We are all waiting with massive amounts of anticipation for NVIDIA's next-gen Ada Lovelace GPU architecture and forthcoming GeForce RTX 40 series graphics cards... but before that, we have something interesting.
NVIDIA's second-fastest Ampere flagship GeForce RTX 3090 graphics card has had a custom BIOS installed, to see how it would perform with less memory, and on a slower memory bus. NVIDIA's GeForce RTX 3090 has 24GB of GDDR6X which was reduced to 20GB and 12GB in different tests, as well as its memory bus being dropped.
For the 20GB test, PRO Hi-Tech dropped down to a 320-bit memory bus, while for the 12GB test the memory bus was dropped to 192-bit. This reduced the memory bandwidth from NVIDIA's usual 936GB/sec on the GeForce RTX 3090 down to 780GB/sec with 20GB + 320-bit memory bus, and just 468GB/sec with 12GB + 192-bit memory bus.
The modder tested both 3DMark TimeSpy and 3DMark Port Royal benchmarks, as well as some games. NVIDIA's GeForce RTX 3090 at pure stock settings with its 24GB of GDDR6X memory with no adjustments hits 18388 points in the Graphics score, while the 20GB model + 320-bit memory bus drops to 17686 points, while the 12GB + 192-bit memory bus hits 13996 points: a large 24% or so drop from its normal performance.
It shouldn't be a surprise that gimping the ultra-fast and huge chunk of 24GB of GDDR6X memory on the GeForce RTX 3090 to 12GB + 192-bit memory bus would drop performance so much, but... well... duh. We're looking at somewhere between 76% and 85% of the performance of the regular RTX 3090 with the 12GB + 192-bit memory bus BIOS, while you have most of (95-96%) of the performance dropping to 20GB + 320-bit memory bus.