[Fozz_uk]

So why the heck is a 64-bit processor better? Can someone give, or link to, a simple explanation?

It's just that everyone knows that the G5 is 64-bit and thus better...but no-one seems to know WHY that makes it better, is it all just a result of Apple's ad campaign?

Cheers
Fozz.

[bimmerphile]

It can process twice as much data per cycle as a 32-bit processor....that being when you have a program that's written for 64 bit.

[Maflynn]

I like to picture it as a larger hiway. if your in traffic jams on a two lane road with lots of traffic lights, then a four lane highway without traffic lights will keep you moving faster. The lanes are the bits (32/64) and the traffic lights is the subsystem waiting to send or receive the data. The G3 and G4 had to wait at times because the subsystem could keep up with the processor.

Mike

[Arkham_c]

There are several factors:

1) When the machine looks for memory, in a 64-bit processor it uses a 64-bit address register (2^64 addresses, 2305843009213693952 bytes) versus a 32-bit address register (2^32 addresses, 536870912 bytes). So right off, you can address more memory, both per process and total.

2) When an application needs to move data between the processor and memory, it does so in 64-bit chunks instead of 32-bit chunks. If there is a lot of data, this results in better performance.

Bear in mind that in most cases, 64-bit means slower, not faster. For smaller programs that don't move around tons of data and work with datasets that can fit within a 2MB L2 cache, a 32-bit processor may actually be faster.

There was a benchmark on 32-vs-64 bit recently on Slashdot if you're interested:

http://www.osnews.com/story.php?news_id=5768

[driven]

Bigger word size.

[fizzlemynizzle]

The ability to address more RAM. A gig is enough to get by on these days, but consider 6 years ago that 32 to 64 -megs- was plenty. What will RAM requirements be like in 6 more years?

[Scotttheking]

Originally posted by Fozz_uk:
So why the heck is a 64-bit processor better? Can someone give, or link to, a simple explanation?

For your average user, it's not any better.

[i_wolf]

I thought that in most cases the Opteron was faster running in 64bit mode by a general margin of 10 - 15% over 32bit mode.
That slashdot article is interesting. But I reckon that its good, for 3d rendering artists and other compute intensive apps that AMD and Apple are addressing this need.

[i_wolf]

http://www.xbitlabs.com/articles/cpu...y/64bit_3.html

[Catfish_Man]

Originally posted by i_wolf:
I thought that in most cases the Opteron was faster running in 64bit mode by a general margin of 10 - 15% over 32bit mode.

That's not because it's 64 bit. It has more registers that it only enables in 64 bit mode. Other 64 bit chips don't have that (they don't need more registers).

[OreoCookie]

For the average user, the single most important advantage is that 64 bit CPUs can handle more than 4 gigs of RAM efficiently whereas 32 bit CPUs can't (there are techniques to deal with more than 4 gigs, but as I said, not as efficient).

For some applications (that you probably won't use, i. e. not Word), 64 bit also brings a performance benefit. On the other hand, some will run even slower on 32 bit.

If you ask "Why is the G5 better than the G4", then the answer is a bit more easy to comprehend: because of the radically new and improved architecture, immensely increased internal bandwidth, the G5 is faster than the G4 (in 32 bit and 64 bit mode).