[Katsunami]

What BWinmill means, is that there are a lot of people who think that Windows XP runs faster because it uses less resources of the computer.

Many people find it a good thing, if the operating system doesn't use any resources. They want the memory to be empty. They don't want it to use the graphics card to draw onto the screen. They don't want it to use the CPU. They think "using less resources" is the same as "running faster because the computer has more time for other things".

That's stupid. Resource usage is not the only thing that determines software speed.

It's the same as saying that BubbleSort is faster than a multithreaded version of QuickSort because BubbleSort is a shorter and simpler algorithm, and uses less CPU power and less memory. It just doesn't work that way.

QuickSort is magnitudes faster than BubbleSort because it's more efficient (despite it being a more complicated algorithm), and a multithreaded version is even faster than that.

But there is an if; a big one.

This is only true *IF* you have the hardware to support that high-powered multithreaded QuickSort software that can use 2GB of RAM.

If you run a multithreaded version of QuickSort that uses loads and loads of RAM on an underpowered single core computer that only has 16MB of RAM, causing it to swap to the drive like an idiot (and a very slow hard drive at that), then yes; the inefficient BubbleSort using 1MB of RAM that doesn't need to swap may actually be faster on that computer.

Then run both algorithms on a current-day quad core computer, offer the algorithms 2GB of RAM, and see how the much more resource-intensive QuickSort blows BubbleSort out of the water. The simple BubbleSort still only uses one CPU core, it still only uses 1MB or RAM, so it's sped up only by the increase in speed of that CPU core, and that's it.

Even better... add graphics card acceleration support to QuickSort (some graphics cards already have over 1000 stream processor cores), thereby making it even more complicated and using even more resources of a modern computer, and then see how it obliterates everything under the sun.

It's the same between Windows XP and Windows Vista (and even more so, 7). If you run XP and Vista or 7 on a PC from 2002, XP will actually be faster. It's what many people did, with Vista, in 2006-2007, causing it to receive the badge of "being slow". (The fact that the driver model changed between XP and Vista, and many manufacturers ignored that up until the very latest bèta version, not being ready with their drivers at launch, is an entirely different matter.)

In the beginning of 2007, many people ran Windows Vista on old hardware for which the OS was not designed. The hardware needed to support Vista was still too high-end to be in most people's home. When 7 came along in the end of 2009, which basically is just an optimized Vista, the required hardware had become standard fare.

As soon as you bring in a multicore computer with enough memory and a good graphics card, then Windows 7 starts to overtake XP because of the fact that it can use stuff that XP can't: better management of large quantities of memory, more memory for caching, more memory per application (if comparing Win7 64-bit to XP 32-bit; almost nobody uses XP 64-bit), graphics hardware acceleration, better support for multicore, better support for hyperthreading, better support for USB3, SATA II / III, and SSD's.

The more powerful your PC becomes, and the heavier and more demanding the software is that you run, the more Windows 7 will overtake Windows XP despite it being a bigger an more resource-intensive OS.

I *want* my OS to use all the sources of the PC as much as possible. Stuff the RAM, use teh graphics card to draw, and so on. The OS is smart enough nowadays to give everything such as memory to an application that wants or needs it.