What does "32-bit" mean?

yekendea pandey 

wow this is the real lecture

Rayane Djeha 

You said that the Athlon 64 had a 64bit register , doesn't that mean that this CPU could access 2^64 of RAM ?

Matthew Suffidy 

I was looking around for something describing how the 386 had 32 bit capability when Linux could use it and not windows. I assume it was just done prospectively and microsoft was behind on it. I think it is important to mention how starting with 32 bit, the preemptive capability existing, and the ability to access address in a straight, non memory segmented manner are the biggest differences.

mohamad saif 

thaaaaanks keep it up

a j 

Good stuff but I prefer to have the simple picture in my head that 64 bit means registers of 64 bit so that you can access 2^64 different pieces of memory. That is still explainable to the sales person that sells the software in my company.

Tamas Szabo 

thanks for taking the time to do this

hans muster 

Hint: With a x86-64 we can use the 64 bit mode, the 32 bit mode and the 16 bit mode. With a 80386+ we can use the 32 bit mode and the 16 bit mode.

Using a 80386+ within the 16 bit mode we can use the 16 bit instruction set and the 32 bit instruction set together with address size and operand size prefixes for to address 4 GB within the 16 bit mode. The only one difference between the 16 bit mode and the 32 bit mode on a 80386+ is the default address and operand size and the usage of the address size and operand size prefixes.

Starting with the Pentium MMX (32 bit CPU) we can additional use the MMX instruction set with eight 64 bit MMX register within the 32 bit mode and also within the 16 bit mode using MMX instruction prefixe.

Using a x86-64 within the 32 bit mode we can use the 32 bit instruction set and the 16 bit instruction set, but we can´t use the 64 bit instruction set within the 32 bit mode or within the 16 bit mode. So the difference between the 64 bit mode and the 32 bit

Joseph Glenn 

Thank you very much.

Juan Medina 

great tutorial ! i love it... thanks for share this video!


Thank you. It really helped.

Albin Håkansson 

nice video, but isn't it the register bit size that determines how much memory can be accessed? Rather than the instruction set bit size?

Peanut Von Nut 

I got 8 gb ram and can only use half so if i upgrade the cpu i can use it?

Israel Karity 

it would be good if you explained about ls\st

so it will be clear why and how longer commands realate to bigger RAM

Mino Marazzini 

So clear and well explained ;)!

mad cobra 

cant we merge 2 2 bit registers to access a 4 bit memory? I remember merging 2 8 bit registers to access 16 b it memory in microprocessors course.

Siwen Zhang 

Clear, Instructive, Great!

Chem Oudom 

thank for good video

Joe Gandhi 

That was a great explanation, thank you!

Rohit Sharma 

good one


Awesome tutorial!


This was the clearest explanation I have found on Youtube. Thank you.

Danley Nemorin 

Great video

Katarina Cvejin 

Thank you.

Mostafa Najmi 

Thank you for this useful video

Bhaskara Kummithi 

Very nice, thank you sir.

Ivo Tantamango 

Thank you


thanks for the explanation u deserve a sub and one like


8 bits = 1 byte. why 2^20 = 1 MByte and not 1Mbit?

Niamatullah Bakhshi 

A special thanks from you sir!

I really have learnt a lot from this and all your  videos .. 

Keep it Up ... :)

Neha Sharma 

Good video.

Michael Knox 

I cannot understand why no comments have been written because this is brilliant. The basics are properly explained for you to master and use for further study. A definite thumbs up from me..


you are great man! please keep up the good work on some low-level aspects of enginnering! it's great!


now..this is some real lecture


Awesome video sir!


really great explanation! thank you!

shah zain 

u look like charlie sheen :D



omkar ramtekkar 

Really awesome.

Please add more tutorials like this.


Great video, thanks for the help :)


You look like the guy in "les incroyables" :)

Awesome tutorial!