Computers: PowerPC tries to shift the paradigm: This week's launch of the PowerMac is Apple's bid to claw back market position. David Hewson poses the key questions

I thought PowerMac was actually called PowerPC. What's the difference?

PowerPC is a computer processor chip developed jointly by computer manufacturers IBM and Apple and chip-maker Motorola. PowerMac is the computer made by Apple using the PowerPC chip.

PowerPC runs much faster and is cheaper to produce than conventional processor chips from companies like Intel, the world's leading chip manufacturer. PowerPC machines will come from many companies, not just Apple, and will run operating systems - the basic software that makes all the components of the computer work together - other than the Macintosh's System 7 operating system. Expect Unix and Windows PowerPC machines over the next year - and completely new operating systems, too. If PowerPC takes off, look to companies like Compaq and Dell, leading suppliers of PC-compatible systems, making machines with the chip inside.

So why should I buy PowerMac instead of an ordinary Macintosh?

PowerMac runs existing Mac applications as fast as an 'old' high-range Mac, but 'native' PowerMac applications - designed for the new chip - go faster than anything seen on a personal computer before. Native applications may be thin on the ground to start with, but should be plentiful by summer. If you need one now, look out for WordPerfect 3.0 which is available for native PowerMac and costs pounds 29 (including VAT) for the upgrade from the normal Mac version, or pounds 140 new.

Will PowerMac software cost more?

In principle, no. Most companies will sell one package for both and the installation software will know which to install. Not everyone is being as sensible as WordPerfect about this, though, so watch out for upgrade rip-offs. Some companies are limiting the upgrade availability period: if you do not fork out the cash now, you have to buy a completely new version for PowerMac. So if you intend to buy PowerMac next year, it may make sense to upgrade earlier.

And the adverts say I can run Windows on my Mac.

Whoa, there. This is not a Windows computer with an Apple system on the front. If you shell out the best part of five hundred quid you will get an extra 8 megabytes of main memory (ram) and a piece of emulation software that lets you run a real version of Windows, but only in 'standard', slower, mode.

Don't I normally run Windows in 'standard' mode?

Not unless you are still running it on a 286-processor PC, which is the electronic equivalent of still life. Most Windows applications run in '386 enhanced' mode on PCs based on 386 or 486 processor chips. PowerMac emulation will not be able to do this before the end of the year. This means it will run Windows applications rather slowly and a few not at all. If it is vital, check first.

If you want to run Windows at breakneck speed go out and part with the best part of pounds 3,000 for a PC based on the latest Pentium chip from Intel, with all the bells and whistles. It will still be slower than a PowerMac running native software and costing half the price. The Windows emulation is there for people who need the ability to run the odd Windows application and maybe something in Dos, the PC's basic text-based operating system, which apparently runs very fast indeed. But why buy a Mac to run something inferior in the first place?

Because I like Windows software.

In fact, Windows software and Mac software are increasingly indivisible. Microsoft will have native PowerPC versions of Word, Excel, PowerPoint and Works on the market later this year and they will be identical, arguably superior, to the same versions running under Windows. All the big Mac software favourites - FileMaker Pro, ClarisWorks, XPress, PageMaker et al - are making the jump too. What is more, the basic Mac operating system is still much better than Windows in most respects. Imagine never having to bother with a Config. sys file again.

So why is Windows so much more popular than Macintosh?

Because Apple, in its wisdom, spent the best part of a decade making everyone pay through the nose for the Mac and only recently realised that this hurt their sales. It may be too late to make much of a dent in the opposition, of course.

Talking of opposition, Microsoft is releasing a new super version of Windows called Chicago later this year that may beat the pants off PowerMac.

The word is that Chicago will put an Intel-based PC on par with the Mac as far as ease of use is concerned, but the power problem still remains. I doubt Chicago will run adequately on anything less than an 8-megabyte DX66 PC, the current top of the range. All of us who were persuaded to buy a 4-megabyte 486 SX25 - the bottom of the 486 processor range - me included, face a good pounds 500 upgrade to get Chicago working properly. But it probably will be excellent. Microsoft, though it is rarely given credit for this, desperately wants to get away from the complexities of Dos. It is expensive employing all those people to yawn and then tell you to change your Files=10 line to Files=20.

But I can't live without Minesweeper.

OK. Wait till next year. Microsoft will bring out Windows NT native to PowerPC machines produced by people like IBM. This will run Windows applications at high speeds and let you play games like Minesweeper without a Config. sys file.

But I want to buy something now.

They love your sort of people back in San Jose. The choice, then, is this. PowerPC is a very, very fast Mac if it is running native software, but do not expect wonders from the Windows emulation. If you want fast Windows, buy an Intel-based PC and if you are looking forward to Chicago, make it a fast one, with plenty of memory, and - am I really writing this? - expect to pay more than you would for an Apple.