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elppa · Jul 9, 2003, 01:27 PM

What does it mean to say a computer is 64 bit? How is this different to a 32 bit computer? Also, I have heard people talk about the Playstation 2 being a 128 bit console. What does the word "bit' mean and what significance does it have.

Sorry if this question sounds stupid!!!

mark9939 · Jul 9, 2003, 01:54 PM

I would do a search for that question, as there have been quite a few threads about the significance of a 64-bit processor.

Judge_Fire · Jul 9, 2003, 02:24 PM

Yes, you'll likely find good overviews on the topic by searching this, or the Mac OS X- forum. For a long, detailed answer, you can see this article from Ars Technica, for example.

J

itai195 · Jul 9, 2003, 02:32 PM

There's a difference between a 64 bit CPU and a 64 bit computer. The PowerMac G5 is not a 64 bit computer.

Anyway I wouldn't get hung up about it, the bit debate is mostly just a lot of nonsense and marketing gimmicks. For example Atari advertised their Jaguar console as being 64 bit, when in fact it was just two 32 bit processors working in parallel with a 64 bit bus.

eddiecatflap · Jul 9, 2003, 03:15 PM

..see ars technica - "it is quite possible that we'll see a game that benefits from greater than 4GB RAM within the next five years"

WOWZERS!

elppa · Jul 9, 2003, 03:52 PM

Originally posted by itai195:
There's a difference between a 64 bit CPU and a 64 bit computer. The PowerMac G5 is not a 64 bit computer.

Anyway I wouldn't get hung up about it, the bit debate is mostly just a lot of nonsense and marketing gimmicks. For example Atari advertised their Jaguar console as being 64 bit, when in fact it was just two 32 bit processors working in parallel with a 64 bit bus.

So Apple are lying then, because on their website it clearly states that the Power Mac G5 is "The world's first 64 bit personal computer"

CubeBoy · Jul 9, 2003, 05:40 PM

bit (short for binary digit) refers to the smallest unit of information. A single bit can hold only one of two values, either a 1 or a 0.

A 64 bit microprocessor can process data and memory addresses that are represented by 64 bits.

In the case of a 64 bit computer, it would mean that the computer's data registers are 64 bit wide and it uses 64 bits to identify each address in the memory.

itai195 · 06:38 PM

Originally posted by elppa:
So Apple are lying then, because on their website it clearly states that the Power Mac G5 is "The world's first 64 bit personal computer"

Well, Apple is being efficient with the truth

They're really referring to the fact that it's the first personal computer to have 64-bit processors (which some would dispute). But one can get pretty anal when discussing whether or not a computer is really a "64-bit computer." There isn't really a definition.

The two significant consequences of using a 64-bit processor is that the G5 can address more than 4GB of memory and that it can work with larger numbers without having to break them up. Whether or not a 64-bit processor adds value to a consumer machine is yet to be seen, but I'm in the camp that thinks it will, eventually.

Crusoe · Jul 10, 2003, 02:44 AM

When you go to the baseball game and go to get a hotdog at the stands, currently there are only 32 vendors with lines of folks waiting to place their order. Due to difference in orders up to 16 of the vendors can become inefficient. So we now have 64 vendors available so you don't have to wait as long. Though if your order is big, it's likely we'll have up to 32 inefficient vendors.

Basically, the chunks of data that can be passed around and processed on a single computation are double that of your current system. You'll be able to watch more of the game rather than wait in line.

mfessenden · Jul 10, 2003, 08:16 AM

Originally posted by itai195:
There's a difference between a 64 bit CPU and a 64 bit computer. The PowerMac G5 is not a 64 bit computer.

Just out of curiosity...why isn't the G5 a 64 bit computer?

tooki · Jul 10, 2003, 12:25 PM

The frontside buses are 32-bit.

In all fairness, each CPU has two such buses: one for each direction. (Other CPUs use one bus which carries data in both directions.)

tooki

PB2K · Jul 11, 2003, 04:52 AM

The atari jaguar Console used 4 x 16-bit processors

drmbb2 · Jul 11, 2003, 06:42 AM

And don't worry about migrating - according to Wednesday's CARS report, Apple will ease you into 64bit processing, starting with 37bit Panther and updating gradually to a full 64bit

OreoCookie · Jul 11, 2003, 08:37 AM

64 bit means that data and (memory) addresses may be (but in case of data don't have to be) 64 bit wide.

This effectively means that

1. You are able to address more than 4 gigs of memory without slow-as-hell paging techniques.

2. For certain applications, being able to directly process 64 bit data means a performance benefit.

What a 64 bit CPU is not: twice as fast as a 64 bit CPU.

As for OS X not being 64 bit: well, as long as you can access 64 bit-specific functions, I don't see any problem with 10.2.7 or 10.3. Apple will slowly rewrite bit by bit of OS X to take advantage of the G5 and its successors.

King_Rat · Jul 11, 2003, 09:05 AM

For most users 64 bit is not a big deal, other than the added memory (after all, we all need over 4 gigs of RAM

). However, when you start dealing with large numbers (over 4294967295) a 32 bit processor will have to take more than one clock cycle to process the number. However, a 64 bit processor can handle up to about 1.8867440737*10^19 befoure it takes more than one clock cycle to process the number. Most of us don't normally care about numbers this big, but some people do (a 64-bit verson of Matlab on the Mac could be nice, if you use Matlab).

As far as the 32 bit bus goes, if the processor wants to get a 64 bit number from RAM it will have to use two read cycles to get it. This will slow down 64 bit computations a little, but it will still be faster than if it had a 32 bit CPU.

I hope that this helps