Zephyr was the second revision. 90nm on both CPU and GPU. Better heatsink and first HDMI model...
I believe the Falcon is the one you have, the first HDMI model to have a 65nm process... Same as mine
Falcons had the 90nm GPU but a 65nm CPU.
Jaspers had 65nm on both.
You can tell them apart by their power requirements (listed near the power socket on the rear)...
Original Models...
Xenon------90 nm------90 nm------No----203 W----------November 2005--------Original release.
Zephyr-----90 nm------90 nm------Yes---203 W----------July 2007--------------Introduced HDMI port. Improved GPU heatsink.
Falcon------65 nm------90 nm------Yes---175 W---------Late September 2007---Introduced 65 nm CPU. Power consumption lowered.
Opus-------65 nm------90 nm-------No----175 W--------June 2008--------------Available as a replacement for Xenon motherboards which have been sent in to Microsoft repair centers. (no HDMI)
Jasper------65 nm------65 nm-------Yes---150 W--------September 2008--------Introduced 65 nm GPU. Introduced on-board flash based memory. Further reduced power consumption.
360 Slim...
Trinity (360s)---Both 45 nm---------Yes--135 W----------May 2010--------------Motherboard redesign used in the Xbox 360 S
Corona (360s)--Both 45 nm---------Yes--115 W----------August 2011------------No more HANA Chip; integrated into southbridge. PSU is 9.86A, down from 10.83A (Only ones manufactured now)