Pascal (microarchitecture)

Pascal is the codename for a GPU microarchitecture developed by Nvidia, as the successor to the Maxwell architecture. The architecture was first introduced in April 2016 with the release of the Tesla P100 (GP100) on April 5, 2016, and is primarily used in the GeForce 10 series, starting with the GeForce GTX 1080 and GTX 1070 (both using the GP104 GPU), which were released on May 17, 2016 and June 10, 2016 respectively. Pascal was manufactured using TSMC's 16nm FinFET process, and later Samsung's 14nm FinFET process.
The architecture is named after the 17th century French mathematician and physicist, Blaise Pascal. 
On March 18, 2019, Nvidia announced that in a driver due for April 2019, they would enable DirectX Raytracing on Pascal-based cards starting with the GTX 1060 6 GB, and in the 16 series cards, a feature reserved to the Turing-based RTX series up to that point.
Details.
In March 2014, Nvidia announced that the successor to Maxwell would be the Pascal microarchitecture; announced on May 6, 2016 and released on May 27 of the same year. The Tesla P100 (GP100 chip) has a different version of the Pascal architecture compared to the GTX GPUs (GP104 chip). The shader units in GP104 have a Maxwell-like design.
Architectural improvements of the GP100 architecture include the following:
Architectural improvements of the GP104 architecture include the following:
Overview.
Graphics Processor Cluster.
A chip is partitioned into Graphics Processor Clusters (GPCs). For the GP104 chips, a GPC encompasses 5 SMs.
Streaming Multiprocessor "Pascal".
A "Streaming Multiprocessor" corresponds to AMD's Compute Unit. An SMP encompasses 128 single-precision ALUs ("CUDA cores") on GP104 chips and 64 single-precision ALUs on GP100 chips.
What AMD calls a CU (compute unit) can be compared to what Nvidia calls an SM (streaming multiprocessor). While all CU versions consist of 64 shader processors (i.e. 4 SIMD Vector Units (each 16-lane wide)= 64), Nvidia (regularly calling shader processors "CUDA cores") experimented with very different numbers:
Polymorph-Engine 4.0.
The Polymorph Engine version 4.0 is the unit responsible for Tessellation. It corresponds functionally with AMD's Geometric Processor. It has been moved from the shader module to the TPC to allow one Polymorph engine to feed multiple SMs within the TPC.
Chips.
On the GP104 chip an SM consists of 128 single-precision ALUs ("CUDA cores"), on the GP100 of 64 single-precision ALUs. Due to different organization of the chips, like number of double precision ALUs, the theoretical double precision performance of the GP100 is half of the theoretical one for single precision; the ratio is 1/32 for the GP104 chip.
Performance.
The theoretical single-precision processing power of a Pascal GPU in GFLOPS is computed as 2 X (operations per FMA instruction per CUDA core per cycle) × number of CUDA cores × core clock speed (in GHz).
The theoretical double-precision processing power of a Pascal GPU is 1/2 of the single precision performance on Nvidia GP100, and 1/32 of Nvidia GP102, GP104, GP106, GP107 & GP108.
The theoretical half-precision processing power of a Pascal GPU is 2× of the single precision performance on GP100 and 1/64 on GP104, GP106, GP107 & GP108.
Successor.
The Pascal architecture was succeeded in 2017 by Volta in the HPC, cloud computing, and self-driving car markets, and in 2018 by Turing in the consumer and business market.