MAME-NES v1.7 is released. This branch contains a major NES/Famicom accuracy update for MAME. The main M6502/NES CPU timing path, APU, and PPU have been heavily reworked toward cycle-accurate behavior. The goal of this work is to improve hardware accuracy while keeping the implementation compatible with MAME's existing NES/Famicom architecture.

MAME-NES Changelog:
Major Mapper updates and PPU Updates
Reworked some mappers
MMC5 is more hardware like
Other mappers have been updated for new PPU code

Download: MAME-NES v1.7
Source: Here