https://videocardz.com/newz/nvidia-enables-resizable-bar-on-geforce-rtx-30-graphics-cards
So it looks like Nvidia has now added support for Resizable BAR on their 3000 series GPUs. AMD were first to market with this feature on Windows which they have dubbed "Smart Access Memory" or SAM for short.
With Resizable BAR support games can reach up to 12% additional performance in some edge cases depending on the title while averages tend to be around 3-5% for games that benefit from it. It should also be noted that some games do not show any performance improvement with Resizable BAR enabled and in some cases even lose a slight bit of performance.
Nvidia has specified a list of 17 compatible titles that benefit from this as opposed to AMD who just offer the ability to turn it on wholesale even if it negatively affects the or has no affect on the performance of the title. It looks like for anything above the 3060 both the latest driver and a special firmware update for the cards are required to enable this feature.
Resizable BAR for those not aware allows the CPU to access the full amount of the GPU VRAM rather than smaller chunks at a time as it has traditionally been in Windows operating systems. It should also be noted that Linux has had support for Resizable BAR for a very long time so this has been a part of the PCI-E spec for a long time but has lay dormant until recently.
Exciting times, I'm looking forward to when developers are able to update their engines to take advantage of and optimize for resizable BAR/SAM natively as the current results for both Nvidia and AMD are completely unoptimized for this.
