While modern systems have gotten more powerful, and a CPU bottleneck with the OS is unlikely, if you are on a lower cost system that is still using an HDD, then windows XP will perform faster.Windows XP is far less IO intensive. the assets for basic functioning, including the kernel, only takes up around 40MB of RAM. Because there is so little to load for the majority of the OS functions, things are very snappy.Upgrading to a newer OS such as windows 7 is more than just dealing with legacy software. It is also heavily dependent on the hardware. Unless you have workers who upgrade their systems every few months, the business will consider the cost of the computers to be something to avoid as much as possible,and thus, will only purchase systems which meet the requirements for the job, and not much more.This also means that when upgrading, the hardware may not handle a new OS without becoming excessively sluggish, and thus reducing productivity.and regaining productivity with faster computers is not worth the cost, if the same thing can be achieved more cheaply, by simply not upgrading the OS to begin with.On a modern PC, and a good HDD, windows XP can offer SSD like snappiness that people come to experience from windows 7 running an SSD. and when you run windows XP on an SSD, things become pretty much instant for all OS functions. If you disable all animations, you will be hard pressed to find something that did not finish loading before the audible click from the release of your mouse button is finished.For many, the goal of the OS is to not get in the way. you simply need something that will start quickly, and allow you to run the applications you want, and provide an efficient UI to manage it all.The OS in its self, is not the goal. (would you run windows 7 or 8 if you can install no additional applications other than what the vanilla OS comes with?)Would you run any of the OS if it came with no applications other than the base OS, and did not alloy you to install anything?Windows Xp is still popular, because it is a good OS.Most people who argue against that, only seem to come up with the argument that the Os is old. they can never give a valid argument explaining why they feel the OS is bad.For the past few years, windows XP had a better security track record than windows vista, 7, and 8. Virtually every new exploit discovered, worked on windows XP, vista, 7, and 8, with the exception of a few exploits that exploited a new feature that only vista, 7, and 8 had.Newer versions of windows, have not made people any safer. it has not reduce the computer repair business cash flow. Users are getting infected the same or more than with windows XP.Think about this suppose you own a business, and everything is working file with 500 workers using windows XP, then someone comes along and tells you to upgrade to windows 7, but doing so will require new hardware, it will not improve security (windows 7 has new security features, but no evidence to show it having and positive impact), all just so the workers can do the same thing they are doing now, at the same pace that they are doing it now.You would likely say no. it is like someone telling you to take apart your laptop completely, in order to replace a CPU heatsink screw, with a new, more shiny one. it will not improve performance in any way, but it will take a lot of work, and time, and money (if you ascribe to the saying, time is money).