Unveiled over the weekend, Windows Vista RC1 comes barely two weeks after Microsoft's release of the pre-RC1 build 5536 - which was in itself an impressive ‘interim build' that by all rights could just as easily have been dubbed Beta 3.

Indeed, you've got to look very hard to detect the differences. Most of the changes take place under the hood - Microsoft says that its tossed more device drivers into the pot, along with tweaking performance. We can vouch for the later: pretty much everything you do in Vista RC1 is snappier and more responsive than previous milestone builds.

However, boot time remains the same finger-drumming minute-long snoozefest as previous builds. We loaded a standard Vista Ultimate RC1 installation onto a 1.7GHz Pentium M system with 512MB of RAM (ie, a typical off-the-shelf system for today's mainstream users) and clocked 56 seconds from cold boot to the desktop.

Likewise, the upgrade from XP to Vista RC1 is also painfully slow, if you choose to go down that path. It took over two hours on one relatively beefy PC at APC - a dual-core Dell (Pentium D with 2GB RAM).

We can only hope that RC1 is weighed down with massive (and we mean massive) chunks of bug trapping code in the start-up stage which, when removed from the final build, will slash start time to at least one-third of what RC1 delivers.

For what it's worth, once you're sitting at a dormant desktop Vista lists its physical memory usage in the vicinity of 250MB, with 60MB being sucked up by background processes. Load up a bunch of apps like Photoshop, several Word documents, several Excel docs, Windows Media Player and Outlook 2003, and RAM usage soars up to over 1GB (with 140MB being used by the Kernel) Much of this is probably Vista's pre-emptive application caching kicking into action.

Poking around the rest of RC1 we found the help system is almost done, with far fewer placeholders and dead ends. For example, pictured below is a complete help page for User Account Control, where previously builds were littered with instances of "insert help text here".

If you missed out on the pre-RC edition then you'll immediately notice Vista's glossier icons, especially for shell folders (such as documents, pictures and music).

From the earliest Longhorn builds to RC1, Vista's icons have undergone more cosmetic surgery than Michael Jackson. Maybe the UI designers have finally done fiddling. They do look cleaner than the previous icons, though, lessening the visual confusion in Explorer, which is welcome.

If your most recent experience of Vista was with Beta 2 or the 5456 or 5472 refresh editions, RC1 is well worth hunting down. It shows Vista is making progress in confident strides rather than awkward stumbles as it nears the finish line.

For example, upgrading from XP now works much better than before. If you had Windows Desktop Search installed on XP, Vista cleanly uninstalls it and rebuilds indexes using its own inbuilt desktop search. In a recent build (5472), Vista left Windows Desktop Search installed but in a non-working state.

Another problem was that Outlook 2003 couldn't access any PST files we had stored on an external drive. This appears to be a problem with the User Account Protection in Vista, because once we modified the security properties on those files to explicitly add our user account, we could open them again.

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