AMD is touting the R600 will feature 700 million transistors (compared to the Radeon X1900 series" 384 million) and a full 512-bit memory interface with support for GDDR3 and GDDR4. On March 30, 2007, AMD will initially debut the R600 as the ATI Radeon X2900 XTX in two separate configurations: one for OEMs (12" layout) and another for retail (9.5" layout). ATI guidance claims the X2900 XTX retail card will come as a two-slot design with a vapor chamber cooler while the OEM version features a quiet fan cooler. 1GB of GDDR4 memory (supplied by Samsung) is the reference configuration for Radeon X2900 XTX.
Approximately one month later, the company will launch the GDDR3 version, dubbed the Radeon X2900 XT. This card features 512MB of GDDR3, lower clock frequencies than the X2900 XTX and is one of the first Radeons to feature heatpipes on the reference design. AMD anticipates the target driver for X2900 XT to be Catalyst 8.36, WHQL expected around March. Radeon X2900 will feature native CrossFire support via an internal bridge interface (no longer a need for the external cable). There is no Master card needed althought any Radeon X2900 can act as the Master card. All three versions of Radeon X2900 are expected to include native HDMI and one 6-pin and one 8-pin (2x4) VGA power connector (both connectors are also backwards compatible with 6-pin power supply cables).