The Inquirer is reporting that ATI is busy prepping their Mobility Radeon X1800XT series to battle NVIDIA's GeForce Go 7800 GPU's. Considering the fact that ATI supposedly had to lower core frequencies to an estimated 445MHz (versus the 500MHz of its desktop counterpart), it is more than a bit surprising to see ATI not opting to wait for their mobile R580 part. If R580 is nearly ready as the rumors suggest and it is similar to R520, giving ODM notebook vendors an R580 part with a few minor changes seems like a much more strategic move on ATI's part. Then again, the Inquirer could be right and we could be seeing ATI's mobile part be a pseudo generation behind the desktop parts.
The desktop range will get a refreshment at the end of January, with the launch of Radeon X1900 series (X1800 will be replaced with X1900). The mobile world will get a product "one semi-generation behind" in the form of a Mobility Radeon X1800 range -unless ATi's marchitecture department gets involved in creative name-gaming.
The lower clockspeed on the mobile part isn't a surprise. Due to thermal issues on designing the mobile package, the clock limits are usually ranged at 500MHz for both the core and the video memory chips. ATi couldn't keep the mobile baby at 500MHz with good thermals, so the core works at 445 MHz, while the memory is ticking over at 495MHz DDR, delivering 31.68 GB/s of memory bandwidth.