memory
Architecture Explained
x86 vs x64
Why does x86 mean 32-bit? Why can't your old PC run new games? Explore the battle of bits, buses, and billions of bytes.
Why does x86 mean 32-bit? Why can't your old PC run new games? Explore the battle of bits, buses, and billions of bytes.
The most painful difference.
4 GB Max
Often only ~3.2GB usable
16 Exabytes
Theoretical limit (18 billion GB)
Why is 32-bit called "x86"?
It comes from the model numbers of early Intel processors which all ended in "86":
"x64" is just short for x86-64, the 64-bit extension invented by AMD.
It's about the highway lanes.
More registers = CPU keeps more data close by = Faster processing.
Visualize how width affects throughput. In 32-bit mode, the "highway" is narrow. In 64-bit mode, we double the lanes and the payload size.
Imagine your computer's memory (RAM) is a library where every byte of data needs a unique address card to be found.
The card catalog only has space for 4.29 billion cards. That sounds like a lot, but it fills up fast (approx 4GB). Once full, the librarian physically cannot issue any more cards. Any extra books (RAM) you buy simply cannot be shelved.
The catalog is upgraded to handle 18 quintillion cards. You could build a library the size of earth, fill it with books, and still have empty catalog cards left over. We will effectively never hit this limit in our lifetime.
1. You have a 64-bit Windows laptop. Can you run an old 32-bit game?
2. You dug up an old PC with a 32-bit Windows XP. Can you install a 64-bit version of Photoshop?
Generally, yes. Not just because of the bits, but because x64 CPUs have more registers (working memory slots) and newer instruction sets. However, for very simple, tiny programs, the difference might be negligible, and 64-bit pointers do use slightly more RAM.
On 64-bit Windows, Microsoft separates applications to keep things organized.
Program Files stores native 64-bit apps.Program Files (x86) stores older 32-bit apps running in compatibility mode.ARM is a completely different architecture (RISC vs CISC). Modern ARM chips (like M1/M2/M3) are also 64-bit (ARM64), but they speak a different language than x64. They use translation layers (like Rosetta 2) to run x86/x64 apps.