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Xtrem unveils 1.2GHz Mac

Liquid cooling to leave Mac fans drooling?

A little-known Swedish start-up is claiming to have crashed the 1GHz barrier ahead of Apple - and by using only a single PowerPC processor.

Xtrem's claims its XtremMac G4 is based on a single PowerPC 7400 chip operating at 1.2GHz. Essentially, the machine appears to be a regular, off-the-shelf Power Mac G4 mobo, processor, memory, PCI cards and peripherals slotted into a new case and overclocked threefold.

To ensure the chip doesn't burn out in a microsecond, the XtremMac uses what Xtrem calls an "active cooling system", but doesn't discuss in detail. Given the degree of overclocking involved here - the motherboard's frontside bus and the graphics card appear to be overclocked too - suggests to us some kind of liquid cooling system. The machine's steel case - 3D rendered, not photographed on the company's Web site, contrary to the site's claim - presumably acts like a large radiator too.

Xtrem isn't the first to try this, though it is the first to do so commercially with a Mac-based system (we seem to recall seeing a liquid-cooled Power Mac based on Exponential's ill-fated PowerPC clone some years back). US-based KryoTech has been offering a AMD Athlon-based box - dubbed the SuperG - overclocked to 1GHz and liquid-cooled down to minus 40 degrees Celsius. The PowerPC 7400 shouldn't require quite such harsh cooling, but it can't be that far off if Xtrem wants to take a 500MHz chip up to 1200MHz and ensure the processor has a reasonably lifespan. The point is, Xtrem's claims aren't unfeasible, despite the fact that some observers reckon the whole thing is a hoax.

Incidentally, that degree of overclocking makes the XtremMac's CPU 140 per cent faster, not 240 per cent, as the developer claims. Still, maths miscalculations aside, the overclocking process does have the benefit of powering all applications, unlike Apple's shift to two processors per box, which will benefit relatively few of them.

Still, Apple will get its kit out more quickly than Xtrem, which has a "by the end of 2000" schedule for the availability of XtremMac. Since the machines are customised off-the-shelf Macs, expect the XtremMac to be offered in a dual-CPU configuration too, and maybe exclusively so, if Apple drops its low-end single-processor G4 by year's end.

KryoTech, meanwhile, is working on an updated version of its 1GHz system that we assume will chill a 1GHz Athlon up to 2GHz and beyond. The new SuperG is set to be released later this summer. We haven't seen either this machine or the XtremMac, but if the perform anything like the 1GHz SuperG, they'll go like the proverbial off a shovel. ®

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