Mobility Radeon 7500 unveiled

As notebooks have come down in price and started to rival desktop PCs in performance, the mobile market has become the fastest growing part of the PC industry. Many new notebooks have processors clocked at or near 1GHz but still have older 8MB graphics chips and are not upgradeable, which makes them less than ideal for 3D gaming. ATI's Mobility Radeon, announced earlier this year, is just now starting to appear in some notebooks. But the company's next step, the Mobility Radeon 7500, seems even more capable of competing with Nvidia's GeForce2 Go for high-end notebook performance.

The Mobility Radeon 7500 has much more graphics power than the current Mobility Radeon, matching the specs of the desktop Radeon 7500. The .15 micron chip hits a top clock speed of 270MHz and has two pixel pipelines with three texture units each. The current Mobility Radeon maxes out at 200MHz on its single-pipeline design, which means the 7500 has more than double the fill-rate capacity. In addition, the fastest configurations of the Mobility Radeon 7500 will use 128-bit DDR, as is typical in desktop boards. Current mobile graphics chips are limited to 64-bit DDR memory, because a wider data path would take up too much room on tiny notebook motherboards. The Mobility Radeon 7500 gets around this obstacle with a dual-channel design that uses16MB or 32MB of internal 64-bit memory in combination with 16MB or 32MB 64-bit memory on the main board. More good news is that the Mobility Radeon 7500 will include transform and lighting, an important feature that its earlier cousin does not have.

For preliminary testing purposes, ATI showed us two similar 1.13GHz notebooks by a major PC maker, one equipped with the fastest current GeForce2 Go and the other with the Mobility Radeon 7500 module substituted in for an earlier ATI chip. We had the chance to run 3DMark 2001 on the two systems at the benchmark's default settings. The Nvidia-based notebook scored 1973, while the ATI-equipped notebook scored 3887--a very good result for a system without DirectX 8-compliant hardware.

In mobile computing, it's not always possible to run at full power. The power-saving features of the Mobility Radeon 7500, dubbed PowerPlay, will drop the chip's speed down to 66MHz by default when the battery is in use. PowerPlay will also dynamically turn off parts of the chip that aren't required by the current workload. These power-saving features will decrease the chip's battery usage even over the current Mobility Radeon. Furthermore, effective DVD acceleration in the Mobility Radeon 7500 can help reduce the CPU's workload and power consumption. Playing a scene from The Matrix on the comparable demo systems resulted in CPU utilization of around 50 percent on the GeForce2 Go machine and only 15 percent on the Mobility Radeon 7500 system.

ATI graphics chips ship in about half of all notebooks, and the company clearly wants to defend its market share at the high-end from Nvidia's GeForce2 Go. The Mobility Radeon 7500 is now in production; however, it does usually take about six months for new graphics chips to make their way into shipping notebooks. This long delay is typical of notebook production, because the system motherboards must be significantly reworked and qualified for each revision. Well before the Mobility Radeon 7500 ships in systems, we'll likely see Nvidia announce its next step for mobile graphics.