Radeon R400 series

ATI Radeon X700/X800 series

Release date	2004–2005
Codename	Loki
Architecture	Radeon R400
Cards
Entry-level	None
Mid-range	X700, X740
High-end	X800
Enthusiast	X850
API support
DirectX	Direct3D 9.0b Shader Model 2.0b
OpenGL	OpenGL 2.0
History
Predecessor	Radeon 9000 series Radeon X300 series Radeon X500 series Radeon X600 series
Successor	Radeon X1000 series
Support status
Unsupported

The R420 GPU, developed by ATI Technologies, was the company's basis for its 3rd-generation DirectX 9.0/OpenGL 2.0-capable graphics cards. Used first on the Radeon X800, the R420 was produced on a 0.13 micrometer (130 nm) low-K photolithography process and used GDDR-3 memory. The chip was designed for AGP graphics cards.

Driver support of this core was discontinued as of Catalyst 9.4, and as a result there is no official Windows 7 support for any of the X700 - X850 products.^[1]