Why does 64bit > 32 bit?

[auveeb]

Why are 64bit processors so good over 32bit processors? What are the differences? I have a x64 CPU but I'm running a 32bit OS at the moment. What would I get out of switching to a x64 os?

 

[HardWarrior]

It's simple, 64bit processors move data around in chunks that are twice the size of 32bit processors at the same operating speed. 64bit units are also capable of addressing more memory.

 

[n0cmonkey]

More memory, more registers, per page execution bit permissions = amd64 > vanilla x86.

 

[karstenanderson]

xp x64 is also bulit on the win2003 codebase, which is vastly improved over xp 32-bit.

 

[Nothinman]

It's simple, 64bit processors move data around in chunks that are twice the size of 32bit processors at the same operating speed. 64bit units are also capable of addressing more memory.

Not true, with MMX, SSE, etc the CPU can do operations directly on 64-bit (or higher, I don't remember the exact number) values. The registers on a 64-bit CPU are larger, but that's a very minor feature from a performance perspective. The main thing the AMD64 chips, well and pretty much every non-x86 chip, have over 'normal' x86 chips is more general purpose registers which means less slow memory access and thus faster performance.

The main difference between 64-bit and 32-bit is the ability to directly address >4G of memory. Even with 32-bit chips you could use PAE to have access to up to 64G of physical memory, but even with that each process would still be limited to 2G of VM (3G on Linux or with some hacks on Windows). There are other advantages that AMD64 has over CPUs, but they're design features of the CPU and don't have anything to do with the fact that the chip is 64-bit.

 

[bsobel]

Originally posted by: karstenanderson
xp x64 is also bulit on the win2003 codebase, which is vastly improved over xp 32-bit.

Not true. That same code base is used for XP SP2.

 

[Brentx]

Originally posted by: bsobel

Originally posted by: karstenanderson
xp x64 is also bulit on the win2003 codebase, which is vastly improved over xp 32-bit.

Not true. That same code base is used for XP SP2.

Yes and XP's code is based off of Win2k. But XP x64 is version 5.2 of Windows, so it has some minor improvements over XP 32bit. I know for a fact they redid the memory manager in XP x64 and Win2k3, which is why it may seem more responsive, and not freeze up during certain situations. They also employed the new rootkit certification program in version 5.2 of Windows, so you can not have a malicious rootkit get installed in your system unless it has been preapproved by Microsoft (kind of like WHQL Drivers in Windows). The newest NT OS's have been based off of Windows 2000, so they are all somewhat similar. I just wonder if Windows Vista will be version 5.3 or 6.0?

 

[Nothinman]

I know for a fact they redid the memory manager in XP x64 and Win2k3, which is why it may seem more responsive, and not freeze up during certain situations.

I'd bet the only changes were related to NUMA because of the say AMD64 does memory management with the on-die memory controller.

 

[bsobel]

Yes and XP's code is based off of Win2k. But XP x64 is version 5.2 of Windows, so it has some minor improvements over XP 32bit. I know for a fact they redid the memory manager in XP x64 and Win2k3, which is why it may seem more responsive, and not freeze up during certain situations. They also employed the new rootkit certification program in version 5.2 of Windows, so you can not have a malicious rootkit get installed in your system unless it has been preapproved by Microsoft (kind of like WHQL Drivers in Windows). The newest NT OS's have been based off of Windows 2000, so they are all somewhat similar. I just wonder if Windows Vista will be version 5.3 or 6.0?

Again, pretty much the same as the sp2 code base. Version # wasn't bumped for compat reasons.

 

[PingSpike]

It isn't. At least not at this time and in any really tangible way.

 

[Brentx]

Originally posted by: bsobel

Yes and XP's code is based off of Win2k. But XP x64 is version 5.2 of Windows, so it has some minor improvements over XP 32bit. I know for a fact they redid the memory manager in XP x64 and Win2k3, which is why it may seem more responsive, and not freeze up during certain situations. They also employed the new rootkit certification program in version 5.2 of Windows, so you can not have a malicious rootkit get installed in your system unless it has been preapproved by Microsoft (kind of like WHQL Drivers in Windows). The newest NT OS's have been based off of Windows 2000, so they are all somewhat similar. I just wonder if Windows Vista will be version 5.3 or 6.0?

Again, pretty much the same as the sp2 code base. Version # wasn't bumped for compat reasons.

I see. I read somewhere that they integrated a lot of Win2k3 code into XP SP2... but I was skeptical about it. I know they did add support for the NX bit with SP2, which was only available for Win2k3