Mac OS X 1057 may have Nehalem Radeon HD 4000 support

In addition to expected fixes, Apple's upcoming 10.5.7 update to Mac OS X Leopard is now claimed to recognize Intel's newer Nehalem architecture as well as AMD's ATI Radeon HD 4000 graphics chipsets.

From:
http://www.appleinsider.com/articles/09/02/28/mac_os_x_10_5_7_may_have_nehalem_radeon_hd_4000_support.html