Thirty years into the evolution of the Flight Simulator, all fans of Microsoft's Flight Simulator 2004: A Century of Flight will appreciate all the areas where the King of Simulators was still far from perfect. Most notably these areas included the representation of populated areas, buildings within cities and dynamic scenery on the ground.

Microsoft Flight Simulator X addresses all these issues in a way that, provided your machine can 'take the heat,' will simply take your breath away. Conurbations are now depicted so realistically that you may imagine you are actually looking out of the cockpit windows! Most major world cites are now super-detailed, with unique buildings pertinent to that city, constructed with a level of detail never before witnessed in a commercially available flight simulator. Airports too offer detail on a level that is unmatched in FS 2004, even with add-on airport scenery. Scenery textures too offer more variation and do not just appear in repeating swathes as they did in previous versions. Textures are subtle, refined and load smoothly and sequentially, giving the user no noticeable redraw as they fly around their newfound virtual world. Trees and bushes in FSX are vastly superior to those in FS2004 - now you can even distinguish different varieties!

Users will love the new dynamic scenery, which is totally controllable within the FSX settings panels. You can add dynamic scenery within airports, including fire trucks, buses and fuel tankers, as well as being able to grace your virtual seas with ferries and leisure craft, and put cars and trucks on the roads. There's still no hint of real people milling around at the airports, but no doubt an add-on will soon become available, making your FS X burst with life even more! With that said, this is such a huge step forward that the lack of people is more of an observation than a criticism - graphically this is so much closer to real life that you won't quite believe it at first.

The FS2004 weather effects have always been excellent, and to my mind no-one has produced an add-on that improves upon them. Fly in FS2004 at dusk and the sunsets are simply stunning. FSX adds the extra smoothness to the weather and clouds that was lacking in FS 2004. This improvement cannot be seen unless you sample both products - the transition between night and day through dusk, and reverse though dawn, is executed so smoothly that you don't even notice changes in brightness and contrast. In FS2004 you could noticeably perceive changes in these levels like notches on a volume dial, but this effect has been eliminated here, as FSX handles these cycles with a fluidity that has to be seen to be believed. Cloud formations remain pretty similar to FS2004, but the rate of change within the weather as you travel has been given the same silky smoothness as the transition between night and day.

The night lighting effects have been so vastly improved in FSX that it bears no resemblance to FS2004 whatsoever. Airport taxiways and runways are now positively bathed with light and you will think, again, that your monitor is a window in a real cockpit! The contrast at night is much more refined than in FS2004 and you can really make out the details and subtle shifts between lighter areas and differing levels of shadow.

The sound, as with FS 2004, is excellent here. Again, real jet, turbo-prop and piston-prop engine sounds have been recorded and used in FSX, offering realism comparable to FS2004. However, again these effects have been refined; although you could adjust all of your different sound levels independently in FS2004, there was often confusion as all the sounds (ATC, cockpit, engines, air-con etc) combined to form a noise rather than distinguishable sounds. FSX clearly separates all these audio channels and makes them all crystal clear - even on default settings. Air traffic control, although in essence similar in interface to FS 2004, has also been given a refinement - there are no stutters or hold-ups and radio chatter has been vastly improved.

The flight dynamics and realism within the simulation of flight itself has not changed much within FSX, but it was already very good anyway. However, coupled with all these operational enhancements, the planes seem more realistic because there are no hold ups in recreating the aircraft's pitch and position, a thing sometimes bugged FS2004. Whereas FS 2004 could not be used as a sightseeing tour, FSX is sightseeing tour and for this reason alone if you thought FS2004 was somewhat taxing on your modest machine then I urge you to upgrade your setup, because Microsoft Flight Simulator X (incarnation 10 for the geeks amongst us!) is a beast!

FS2004 would run on fairly mediocre systems, think again if you want to use this latest instalment from Microsoft on an older machine. Jokers within the department responsible for Flight Simulator recommend the reviewer have a machine boasting at least 3GHz with 2GB RAM and a 512MB graphics card (recommended not minimum specs). It would seem that they are joking - but they are deadly serious and if reviewers are urged to use these specs then the general public would also benefit from basing their machines on this absolute minimum.

My XP test machine, while running one of the most comprehensive set-ups money can buy, did not fully utilise this program. This software is written to be fully tested on machines running Windows Vista. To this end I rebooted and switched partitions to run Vista Beta and installed FSX on Vista. Although not the final release of this operating system and with certain drivers still waiting for their Vista versions to be released, there was a marked improvement. For installation, be prepared to sacrifice a whopping 14GB of hard-drive space (and you thought 1.8GB was large for FS 2004!) This extra room, needed for scenery files, is well used, as the terrain-mesh is vastly denser than it was in FS2004, where a third party terrain mesh would use approximately 14GB in total - so don't be alarmed at this seemingly hard drive eating standard requirement, because the result is well worth the sacrifice!

Installation is as you would expect from Microsoft - painless and totally automatic - but be prepared to wait for a while to play it; 14GB takes time to install from two DVDs. Once installation and decompression has taken place, the software asks you to activate your installation using the serial number. This is a requirement and FSX uses serial number and DVD disc verification in its quest to prevent piracy. You must be connected to the Internet or have access to a phone to do this and when I tried automatic setup over the Internet the server was repeatedly unavailable an issue that I believe a number of users have encountered. Because of this I had to no choice but to settle with the inconvenience of phone activation.

When all this setting up has finally completed you can launch the game. On first boot it takes a while to load and I noticed an irritating soundtrack had been added to the welcome screen! This minor irritation aside, not very much has changed within the setup screens or general interface with the user and for that I am eternally grateful, as it has taken an age for me to memorise all the shortcuts and switch assignments and I'm glad I won't have to repeat the exercise. There have been some improvements with the interface though, including the fact that FSX does not pause while flicking through the menus and changing view modes like FS2004 does. A nice touch in the ATC window is the default setting of history view, where you can see your conversation laid out as if you were in an ATC chat room! Many improvements like these add to the feeling of slick fluidity that FSX undoubtedly possesses - planes can be previewed before they are loaded and the interface looks much more modern.

To quickly test the software, while not adjusting any display or realism settings, I launched a flight from Gatwick to Manchester. My initial impression was a little disappointed to say the least - my FS2004 runs more detailed and sharper scenery and the planes on FSX default settings were just downright abysmal! Initially I also thought FS2004 ran a lot smoother, so I decided to make some adjustments! After tweaking with the many display settings available and adding a little air traffic, as well as ground and sea traffic, I restarted my flight. And what a difference - as I described earlier, the graphical experience can only be described as photographic!

The planes themselves are well represented and a welcome addition to the large Boeing jets is the Airbus A321, the first Airbus in a standard release of Flight Simulator! Also a nice addition to FSX is the Bombardier CRJ700. All these positives are somewhat tempered, however, by the continued exclusion of real world airlines in the livery line-up, and while I accept that it would have been a massive task to include a good selection of real world airlines, a few would have been appreciated in simulating maximum realism!

The multiplayer mode has now been improved to offer the capability to share aircraft control with a friend online (if you trust them!) Up to eight players can share one set of simulated skies for the ultimate Flight Simulator multiplayer experience, although I was unable to test this feature, as none of my friends have FSX yet, or powerful enough machines to utilise it fully, for that matter!

I cannot recommend FSX to you all just yet, because in order to enjoy all it offers to the full you need a truly mighty PC! If you don't care and opt for this game anyway, and run it on low settings, it will look remarkably like FS2004, except FS 2004 runs much smoother on a modest machine. While many claim that FSX is not the leap forward FS2004 was when it was released, I beg to differ - not just because of many improvements and additions, including 55 great interactive missions and new traffic gracing the land and sea, but fundamentally because of one reason: the incredible terrain mesh! FS2004 by default offers terrain mesh centres of 1.2 km apart and can only be changed by adding new mesh information. FSX on the other hand allows the user to begin at 305m and offers settings down to a fantastic 1m! Add to that the truly beautiful textures offered by FSX by default and you have a monumental package.

I urge all of you to give FSX the time and investment that FS2004 has enjoyed before casting you vote! After all, FS2004 has enormous amounts of add-on material and functionality improvements available to enhance the experience, and at what cost? FSX Deluxe will only set you back £60 but adding all these packages to FS2004 will set you back hundreds! FSX sounds like good value to me. Indeed, how can any of us really argue with Microsoft, who says that "The latest instalment... will serve as the graphical benchmark for games on Windows Vista." There you have it, straight from the horse's mouth! Wait for Windows Vista if you want to enjoy this offering to the full (and throw in a NASA specification machine to boot!) but that aside, Microsoft Flight Simulator X is the most advanced Flight Simulator ever to reside on the PC and the most significant advance in the Flight Simulator franchise to date.

Reviewed by Reuben Glossop for AceGamez (All Rights Reserved).