Even if Intel's Turbo Memory hasn't been quite the hit thatwas expected, most people agree that solid state storage will one day replace50-year-old hard disk technology. But the question is - when?

Just around thecorner, for the last decade

The Solid State Disk (SSD) has been lurking in the wings sincethe 1990s. I can remember meeting a company in about 1996 which was touting thetechnology. Back then, a few grand would get you a few MB. It made forinteresting news, but was only viable for some very specialised applications,where low power of shock resistance were paramount.

But now we are starting to see SSDs offered as an optionwith high-end enthusiast desktops and notebooks. For example, Dell's latestInspiron XPS notebook, the M1730,offers a 64GB SSD as an alternative to the standard 200GB SATA drive. Or Vadim's Fusion LQX has a couple of 32GB and 64GB SSD options alongside the more usual parade of WesternDigital Raptors and Hitachi or Seagate 1TB monsters.

So, if you really care about performance hardware, shouldyour next PC have a Flash memory hard disk? Well, it's still not a cheap choice. Dell's 64GB SSD is a whopping £750 premium, and where a 1TB desktophard disk is around £200, a Samsung SSD is closer to £300 - for just 32GB. The Mtron drives available from Vadim start at £800.

Flash by name, butnot by nature?

Aside from price and capacity, SSDs haven't generally managedto trounce hard disks on performance just yet, either. With sub-1ms accesstimes, they are great at finding files. But the sustained throughput with mostcurrent models is still behind hard disks.

For example, Samsung's 32GB SSD can only manage a 50MB/sec read rate and about half that when writing. Western Digital's Raptor 150 achieves75.5MB/sec on average reading or writing - and 90MB/sec in its fastest sectors.

This is where the new Mtron MSP 7000 SSD models are gaining interest.They are nearly triple the price of Samsung's, but the sustained read is closeto 110MB/sec across the entire disk, and writing is only about 20MB/sec behind.So the Mtron drives, currently only available up 64GB, really are a viablealternative to a Raptor.

But that's only if you happen to have a grand to spend on ahard disk. Most of us don't really want to spend that much on the whole PC. Theslower Samsung SSDs aren't so astronomical, but they aren't a performanceupgrade. They could improve the battery life on your notebook, but putting onein your desktop will only save the planet a bit.

In other words, the hard disk is still in no danger of beingreplaced by Flash memory anytime soon, unless you're a speed freak with verydeep pockets. But in taking the performance crown, the SSD has surmountedanother important hurdle. Now all we need is much larger ones for much lessmoney... so see you in 2009.