Could you tell me something about x86 operating systems?

You probably means that Vista 32-bit and 64-bit.

32-bit known as the number of bits (the smallest unit of information in a machine) that can be processed or transmitted in parallel, or the number of bits used for a single item in a data format. The term when used in conjunction with a microprocessor indicates the width of the records, a special high-speed storage area within the CPU. A 32-bit microprocessor can manage data and memory addresses are represented by 32 bits.

64-bit therefore refers to a processor with registers that store 64-bit numbers. A generalization would be to suggest that the 64-bit architecture would two times amount of data that the CPU can process per clock cycle. Users will notice increased performance due to a 64-bit CPU can handle more memory and larger files. One of the most attractive features 64-bit processors is the amount of system memory can support. 64-bit architecture will allow systems to address up to 1,000 GB of memory. In the current systems of 32-bit desktop, you can have up to 4 GB of RAM (provided your motherboard can handle that much RAM) which is divided between applications and the operating system (OS).

x86 is a CPU architecture. Originally, this code refers to the Intel x86 series of processors(eg, 286, 386, 486). X86 refers to any processor that supports the instruction with the Intel 8086 and higher. This includes the Pentium, Pentium II, Celeron, Pentium III, Pentium-4, Pentium D, Core-Duo, Core 2 Duo, Core-i7, Atom, AMD Athlon, Sempron, Athlon 64, Phenom, and Geode.

If your CPU supports 64-bit processing, then yes, you can install the 32 bit and 64 bit Vista.