Can someone explain the 64-bit / Photoshop CS4 thing to me?

I keep seeing references to 64-bit computing on PCs and the expectation that PS CS4 will work well with this.

 

Are there even beta versions of CS4 yet, or is this mere speculation? Is there an explanation somewhere that someone

can point me to so I can learn what this is about? Thanks.

http://www.google.com/search?q=64-bit+%2F+Photoshop+CS4&sourceid=navclient-ff&ie=UTF-8&rlz=1B3GGGL_enUS176US229

The next operation systems will all be 64 bit since we now need more than 4 gigs of memory, so it makes sense that CS4 will work right along side that. Photoshop takes up a fair bit of processing power so I would imagine that the 64bit version would run much faster. IMO beside some useless or useful new features that Adobe adds, I cant see how CS3 and CS4 32bit will differ that much.

"Photoshop takes up a fair bit of processing power so I would imagine that the 64bit version would run much faster."

 

For "normal" DSLR image sizes, we're seeing gains of around 20%.

On computers that use Intel's Core 2, upcoming Core i7, or AMD's processors, 64-bit mode is faster than 32-bit mode

even if you don't have more than 4GB of RAM. The reason is that in 64-bit mode, the processors can hold more data

inside the processor itself, without having to move data back and forth between the processor and the relatively much

slower RAM. Other processors, such as PowerPC or Itanium, are equally efficient in 64- or 32-bit mode, and only benefit

from the extra RAM.

 

For the technically minded, the reason is that the x86-64 instruction set architecture, among many other improvements

to IA-32, doubles the number of general purpose registers from 8 to 16, doubles the number of XMM SIMD registers (8 to

16), and adds an addressing mode that allows referencing relative to the IP register (which speeds up shared libraries or

DLLs).

Adobe has chosen not to developed CS4 in 64-bit for OSX. It will only have native 64-bit support on Windows machines. The reason "64-bit" is important is that a 32-bit register can only support 2^32 addresses, which is equal to a maximum amount of 4GB. A 64-bit computer uses 2^64 addresses, which is equivalent to billions upon billions of gigabytes of RAM. Windows Vista x64, for example, will "only" address 128GB of RAM, which is much more than you are likely to use these days, but much less than the theoretical limit.

 

So, if you use a 64-bit computer, you are likely to use 8GB of RAM or more, as you are not limited to a 4GB maximum as you are with 32-bit computers. All the RAM in your computer can also be used by Photoshop, and the 64-bit instruction set can used by Photoshop CS4. This is a contrast to 32-bit systems were each application has a limit on the amount of RAM it can address or use.

 

Pretty much, the new "performance" workstations will have an edge if running Windows x64. Even though OSX Leopard has 64-bit support, Photoshop CS4 will not work with it, and will only run as fast as a 32-bit application, and it cannot address as much RAM as the Windows equivilent. If you are running a Mac Pro with 8GB of RAM, I think I'm correct in saying Photoshop CS4 will still only be able to address 2GB, since it is a 32-bit program?

>Adobe has chosen not to developed CS4 in 64-bit for OSX.

 

Actually, it was Apple that killed off 64 bit Carbon libraries that Mac Photoshop depends on. That's the reason that Adobe

"chose" not to do a 64 bit version for OSX. Adobe had relied upon Apple's promise to do 64 bit Carbon and then Apple

killed 64 bit Carbon. So, if you wish to place blame, I would look towards Apple, not Adobe...Adobe will have to move over

4 million lines of code from Carbon to Cocoa and that st gonna take time-too much time to do a Mac 64 bit CS4 version.

<i>A 64-bit computer uses 2^64 addresses</i>

<p>

A 64-bit computer <i>can</i> address 2^64 addresses, but most don't. AMD64 processors use only the low 48 bits, for an

address space of 2^48. But your fundamental point is that 64-bit processors have a much larger address space than 32-bit

processors, and that's definitely the case.

<i>So, if you wish to place blame, I would look towards Apple, not Adobe</i>

<p>

There is blame on both sides. Apple has pushed developers hard for years to move to the Cocoa API. Adobe themselves

used Cocoa for Lightroom, so they weren't entirely ignorant of the roadmap. (And that's why Lightroom is 64-bit capable.)

Apple chose to phase out Carbon earlier than they originally promised, which is bad faith. <p>On the other hand, I'm not certain why porting

millions of lines of Carbon code to 64 bits is easier for Apple, especially when Cocoa is already 64-bit ready, than porting

millions of lines of PS code to Cocoa is for Adobe.