GeForce 400 Series

The GeForce 400 Series is the 11th generation of Nvidia's GeForce graphics processing units.

At launch, no product was available with all the stream processors active: the GTX 480 has one group disabled, the GTX 470 has two groups and one memory controller disabled, and the GTX 465 has five groups and two memory controllers disabled.

On 30 September 2009, Nvidia released a white paper describing the architecture: the chip features 16 'Streaming Multiprocessors' each with 32 'CUDA Cores' capable of one single-precision operation per cycle or one double-precision operation every other cycle, a 40-bit virtual address space which allows the host's memory to be mapped into the chip's address space, meaning that there is only one kind of pointer and making C++ support significantly easier, and a 384-bit wide GDDR5 memory interface.
While the GT200 had 16 KB 'shared memory' associated with each shader cluster, and required data to be read through the texturing units if a cache was needed, GF100 has 64 KB of memory associated with each cluster, which can be used either as a 48 KB cache plus 16 KB of shared memory, or as a 16 KB cache plus 48 KB of shared memory, along with a 768 KB L2 cache shared by all 16 clusters.

On February 2, 2010, Nvidia tweeted the official titles of the GF100 (Fermi) retail cards, the GeForce GTX 480 and the GeForce GTX 470.

February 22, 2010: According to Nvidia's twitter update, the Fermi based Geforce GTX 400 series will be "unveiled" at the PAX East 2010, in a later update Nvidia released the launch date of March 26, 2010 for the GTX 470 and GTX 480 to clear up confusion over the PAX announcement.
The quantity of on-board SRAM per ALU actually decreased proportionally compared to the previous G200 generation, despite the increase of the L2 cache from 256kB per 240 ALUs to 768kB per 512 ALUs, since Fermi has only 32768 registers per 32 ALUs (vs.

This allows Nvidia to enable all 16 SMs (all 16 cores), which was previously impossible on the GF100 "NVIDIA GeForce GTX 580".