- No, it does not make your computer hardware run any faster.
- It may make the common software applications they provide for you run faster, depending on how your old machine is configured.
As indicated in their How It Works page, it is actually a USB key holding a Live USB Linux Distribution.
There is thus no hardware involved to make the computer faster (and they do not claim there is), except if your hard drive is slower than a flash USB stick. It is only a replacement for the software that is currently installed on your computer by (supposedly) lighter and faster software.
Your PC will thus remain as fast as it used to be (from a hardware point of view), and a benchmark would probably not show much difference between a clean system and Xtra-PC.
It might feel faster though, thanks to the alternate software Xtra-PC runs – the actual result will depend on how bloated your computer currently is, as stated in their FAQ. As they indicate too, you might not be able to run the same software you are used to, so you would not be able to compare the speed of those.
As to whether it is a scam, anyone can judge considering the following points:
- They do not advertise what Xtra-PC actually does on the main and ordering pages;
- You basically pay for a 8 to 128GB USB key, preloaded with a lightweight Live USB Linux Distribution;
- They provide support and a money-back guarantee;
- They indicate that they provide the source code on request, so it looks like they respect the GPL.
I could not find any actual performance tests online (only a blog post indicating a 29% boot speed improvement over Windows XP). It would be especially useful to compare the different models of Xtra-PC, as they claim some are faster.