ATI Mobility Radeon Preview

Some Specialties

The Mobility Radeon also has some aspects that ATI is betting will be extremely popular in the mobile market. First off is a hardware feature of the chip known as inverse discrete cosine transform, or iDCT for short. As we showed in our DVD Roundup, iDCT is able to significantly reduce the amount of work that a CPU has to do when performing DVD playback. By offloading some of the work normally placed on the CPU, ATI claims that iDCT is able to increase battery life by 20 to 30 minutes when playing back DVD movies.

The second new technology that the Mobility Radeon brings to the table is its power management technology. Much like Intel's SpeedStep technology, the power management on the Mobility Radeon allows the core to operate at two different clock speeds and voltages: a "low" speed when running on battery and a "high" speed when plugged in. Also added is the ability for the user to dynamically change the clock speed and voltage to anything he or she wants. Naturally, we will have to wait before we see what kind of difference this technology makes, but it should prove to be interesting.

A Few Downsides

You may have noticed that while discussing what features the Mobility Radeon gets from the desktop Radeon, the Radeon's Charisma engine was left out. The reason for this is that ATI essentially cut this part of the chip out in order to save space, money, and power.

By cutting out the Charisma engine, ATI essentially removed the Mobility Radeon's T&L support. Considering how much the Mobility Radeon shares with the Radeon, we were surprised to hear that the T&L engine had been cut. It was only six months ago that ATI was proclaiming that their T&L engine was superior to all others.

The biggest disappointment with the loss of the T&L engine is the Mobility Radeon's inability to move the common transform, lighting, and clipping calculations from the CPU to the graphics chip. Doing so would undoubtedly offloaded some strain placed on the CPU and diverted it to the less power hungry and much more available graphics chip, in a similar manner that iDCT was able to do during DVD playback.

As we have mentioned before, T&L support does not drastically alter the nature of gameplay currently, but it seems that it is just a matter of time before it does. Although right now the lack of T&L support may cost the Mobility Radeon very little when it comes to performance and battery life, things may change as games continue to evolve.