Since Compaq and Toshiba developed the first laptop computers in the 1980s, manufacturers have been struggling to balance size, weight, portability, power and especially, battery life.
Today's laptops can hardly be compared to those mono-screen, DOS-powered beasts that often did not even feature a hard disk.
The current generation of laptops rip through business applications, and make a fairly decent stab at tasks that even a couple of years ago, were confined to the desktop workstation: video editing, recording music, 3D modelling, scientific visualisation.
The real trade off is now between performance, and battery life. A lightweight and portable computer is of little use if it has to be chained to a power cord, but high performance usually means more recharging.
The chip makers, though, believe they are now close to breaking an important, practical and psychological barrier: the "all day" battery. Intel's Core i series of processors, especially in their Sandy Bridge configuration, combine powerful graphics and multi-core chips that lend themselves to laptops.
Rival AMD thinks it can go a step further. This week, it announced its next generation of accelerated processing units, or APUS, formerly code-named Llano.
The Llano chip can hold up to four x86 CPU cores, and up to 400 Radeon GPU (or graphical processing unit) cores, as well as dedicated hi-def video. AMD claims that this brings supercomputer-class performance, with 400 gigaflops of power in a notebook, as well as more consumer-focused features, such as the ability to smooth out jerky video footage.
The real benefit for mobile workers, and their employers, will be in improved battery life. When chip makers were chasing ever-higher clock speeds, battery life on portable computers suffered. Battery technology has, so far, failed to keep up with Moore's Law, and ever more powerful devices are demanding more power than the battery engineers can deliver.
The move to multi-core processors has helped somewhat and the move to specialist auxiliary processors, especially for graphics, will help further. AMD, for example, is claiming a 50 per cent increase in battery life, without reducing computer performance, through its latest APUs. The new chips should deliver 10.5 hours of "resting battery life", AMD says, or allow PCs to last long enough for users to watch "multiple" HD movies on one charge.
For computer users, the idea of a machine that can be charged overnight, and then run all day, is very appealing. Much of the attraction of tablet devices is actually their long battery life, and the experience of businesses deploying the iPad is that there are applications where portability and "autonomy", or the ability to work without wires, trumps raw performance.
It could be that chips such as Llano and Sandy Bridge tip the balance back from tablets to laptops, at least for a while. And it should cut the queue for the power sockets down at Starbucks.
Stephen Pritchard is a contributing editor at IT PRO.
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