Could anyone explain what this is (x32 platform)?
When I run this (x32 platform QT) on windows 7 x64, it crashes and out to windows.
x32 seems to be different from x86, am i right?
secondly, the link to official online installer is extremely sluggish, is the load often too high?
tried that for many several times already.
It's just another example of the naming conventions mess. x86 is an instruction set that exists in many architectures, including 32bit and 64bit flavors. Over the years x86 and 32bit x86 called IA-32 started to be used interchangeably (because it was the only flavor) and then even with win32, which is not entirely correct, as win32 can also refer to ARM instruction set.
Then along came 64bit processors and a new naming hell was born. It is called x86-64, x64 or AMD64(because AMD introduced it first). And then there's also IA-64 which is an incompatible take on 64bit processing from Intel...
The point is very few people get it right these days and when you see something like x32 and x64 it actually means IA-32 and AMD64.
So to answer your question: yes and no. x86 and x32 are not the same thing(I don't think x32 is a "thing" at all) but the person that named these downloads meant it like they were, and to be honest it's just easier on the eyes that way.
As for why it crashes - it's nearly impossible to tell without some details. What actually crashes? The installer, Qt Creator, the compiler or your program using that Qt distro?
I see, so I just ran QtCreator.exe IDE of x32, so it wouldn't run, so it should be normal. But the frustration is I can't get fast download from the QT official link, it takes a great deal of time to download the online installer and the download often times broken randomly and I had to restart and over and over again. So I probably have to wait longer. Are there any alternative download sites for me?
No, the x32 package should work on both 32bit and 64bit Windows.
As for the downloads speed. You can try to switch to "offline installers":http://download.qt-project.org/official_releases/qt/5.2/5.2.1/ and us a browser download manager that can help you with lost connections and restarting (eg. "DownThemAll!":https://addons.mozilla.org/pl/firefox/addon/downthemall/ for firefox).
You can also try one of the "mirrors":http://download.qt-project.org/static/mirrorlist/
x32 generally refers to using a 32 bit memory model with x86-64 architecture extensions like extra registers. It's not an actual separate architecture from x86-64 ("x64"), just a different programming model / binary format. Generally speaking, x32 binaries would require a 64 bit OS to run, certainly a 64 bit CPU. It's relatively obscure, and generally not worth spending time on.
bq. x32 ABI (x32 application binary interface) is an application binary interface project for Linux kernel that allows programs to take advantage of the benefits of x86-64 (larger number of CPU registers, better floating-point performance, faster position-independent code shared libraries, function parameters passed via registers, faster syscall instruction) while using 32-bit pointers and thus avoiding the overhead of 64-bit pointers.
wrosecrans and MuldeR
Yeah, so there is a x32 "thing", but since we're talking about a MinGW (Windows) repo that is clearly divided to 32 and 64 bit I don't think any of those apply here and neither of it was meant in the file names.