Alongside its desktop and laptop GPU announcements at CES 2021, Nvidia has revealed that it will start supporting Resizable BAR functionality from February.
Resizable BAR has been part of the PCIe specification for years, but AMD were the first to utilize it last year with what it called Smart Access Memory. This allowed Radeon RX 6000 GPUs and Ryzen 5000 CPUs to directly communicate, letting the processor access the entire batch of GPU memory instead of it being served up in 256MB chunks. This overcomes one of the biggest I/O limitations in PC hardware today.
Smart Access Memory requires specific hardware to work, but Nvidia is proposing a solution that works across both Intel and AMD CPUs. Intel has already confirmed support with its new 11th generation H and S series processors, while AMD has yet to officially announce which CPUs it will support.
Nvidia is launching support for Resizable BAR with its new RTX 3060 in late February, along with support for its new RTX 30-series laptop chips. Nvidia is also working with motherboard manufacturers to help them provide VBIOS updates for the rest of the RTX 30-series desktop GPUs later in March.
Smart Access Memory has had mixed results in games thus far, with AMD hardware showing performance increases of up to 20% in some cases while losing performance in others.