I know this the been discussed here before, but with the expected release of AMD64 chips in september I've started thinking about them again.

I know the new AMD chip will run old programs, but is that all it will really do. Looking at the docs it doesn't seem to do anything that a P4 doesn't do, well ignoring the obvious 64bit addressing and instructions but 32bit has always been enough for me. I only have half a gig of ram anyway.

The intel chips with a new assembly language on the other hand seem much cooler.
Posted on 2003-07-13 16:57:11 by Eóin
64-bit addressing isn't about how much ram you have - it's about how much address space your software needs. This is a common mistake to make. Every program that runs on Windows has an addressable 32-bit space (not really, but I'm being general) -- even if you only have 16 megs of ram. Within the scope of a single program it is convenient to reference objects by their memory address because it is unique. The actual object can be in virtual memory or a memory mapped file, etc.

So, the question is: Do you run software that requires 64-bit address space? Most people will not need 64-bit chips for the address space. Personally, I just want to play with all the extra registers - I'd buy an Itanium if I could afford it. :)

Intel's new instructions have limited use, and some are already present in 3DNow! Professional, iirc. New instructions are always cool, too. :)
Posted on 2003-07-13 17:36:18 by bitRAKE
32 bit has never been enough for me. even when i started in vb. and when in i got to asssembly only 6 usable regs, i usualy make algos that have 15+ varibles that i could store in a reg. i dont care if amd doesnt have any new instructions with them. but there compatability is a big+ speed too! when theres enough software out there(c++,asm compilers) i will get one.
EDIT: i have 1 gig of ram i can go up to 3 gigs, i might too.
Posted on 2003-07-13 17:47:31 by Qages
Yes, I almost forgot about the extra R8-R15 general purpose regs, and even the xmm8-xmm15 128bit regs.

bitRAKE you're right of course about the address space, I ment I've yet to have a need for more than 512mb of ram, never mind enter the realm of 64bit addressing.

All the new regs would be cool, and I can think of a couple of good uses for those Itanium instruction so they wouldn't goto waste. But its hard to justify the price though for what ultimatly isn't needed, just wanted. :(
Posted on 2003-07-13 18:14:56 by Eóin
I just been browsing the Itanium Manuals again, I spotted something surprising; 1st manual, 1st page I quote "A Key feature of the Itanium architecture is IA-32 instruction set compatibility"

I though only AMD offered compatibility, or is this only some sort of emulation.
Posted on 2003-07-13 19:25:11 by Eóin
IIRC, the software emulator created by Intel beats the hardware emulation on the Itanium CPU! I remember reading how absolutely slow it was and virtually abandoned on the Itanium II - which hardly makes it a feature. :)

http://www.pcworld.com/news/article/0,aid,110402,00.asp
Posted on 2003-07-13 19:31:08 by bitRAKE

IIRC, the software emulator created by Intel beats the hardware emulation on the Itanium CPU! I remember reading how absolutely slow it was and virtually abandoned on the Itanium II - which hardly makes it a feature. :)

http://www.pcworld.com/news/article/0,aid,110402,00.asp



Now thats bad......

But I heard that was one of the reasons why the Itanium wasn't very popular.

How long before you think general consumers will need a address bus greater than 32-bits in width? I myself only have 256MB RAM..
Posted on 2003-07-13 20:40:17 by x86asm

How long before you think general consumers will need a address bus greater than 32-bits in width? I myself only have 256MB RAM..
Well, I have 1 GB of RAM, but I really only notice the difference in UT2003 - I can quit the game and continue programming with no pause from windows. I know many people that have to reboot after running UT2003 - Win98 just isn't able to recover the resources correctly. Maybe it's bad programming? Win2K/XP is the only way to go. :)

I don't think general consummers will ever need 64-bits of address space - there are better solutions, imho. Segment registers can be used for anything needing more address space. The external address space can be increased without changing much of the internal design. Current architecture can address 64GB of physical memory and we are a long way off of needing that much. Video cards with 1GB of RAM isn't that far off. :)
Posted on 2003-07-13 21:30:57 by bitRAKE
Hi, bitRAKE

Speak for yourself ;) ! The last machine that I had whose RAM matched or exceeded its processor's address space was my Apple IIe. I always want my machine to hold the maximum possible RAM. If my machine could hold 4GB now, I'd have 4GB in it. I believe that you should always have the maximum possible RAM. You can always find a use for it. I have a weather simulator on my machine now. Just think of the improvements that a 64 bit processor and 64GB or greater RAM would mean to such a program. In fact, I think that the current video editing software would easily use 64GB of RAM if you had it in your machine. GB RAM video cards? Yes! I look forward to the day when I can buy one.

Charles
Posted on 2003-07-14 09:28:28 by cdquarles

I don't think general consummers will ever need 64-bits of address space

"640 kB should be enought"...

Soon the OS alone will requre that amount of memroy as minimum req. :(
For each 18 months (or so) that goes 640 kB will become more and more laugthable, it has so far, can you imagine 640 kB of RAM? Ther were a time when that was more than needed, where is that time? Where is the time when the OS was _completly loaded_ when you started typing? (now days it still loads teh OS when you can give input and get response)

I wouldn't be surprised if we within the next 15 yrs will have "standard" laptops running at 100 GHz with 2 TB of RAM, a HD on 280 TB... (Imagine the super computers, yum yum ;) :grin: )
Posted on 2003-07-14 09:53:39 by scientica
Since last week I am the proud owner of a 64bit UltraSPARCIIi with 333Mhz and 2mb cache :)

Didnt have time to do some "real" work with the machine yet tough :(
Posted on 2003-07-14 09:58:18 by bazik
cdquarles, you and I are not general consummers. ;)

scientica, we will certainly expand to more, but I don't think it'll be the same type of system we have now - it doesn't scale well. Instead I believe it'd be better to design systems with multiple processors with separate address spaces (maybe a little overlap). When your thinking about the general consumer marketing has to be taken into account - what architecture will sell to the masses and have longterm appeal. The server market is different.
Posted on 2003-07-14 10:17:31 by bitRAKE
Hi, bitRAKE

Hmm, yes; but who are we to make such an assumption ;) , since that is up to the general consumer. When I wear my computer consultant hat, I advise my customers to buy as much RAM as they can afford. The more RAM they have at the beginning, then the longer time it will be before they have (or want) to add it.

Charles
Posted on 2003-07-14 10:54:35 by cdquarles
cdquarles, I would hope my 20+ years working with computers and helping others use computers would give me some insight. This is just my opinion, though. Sure, it's good advice to buy as much memory as you can afford, but that doesn't mean 64-bit addressing is needed.
Posted on 2003-07-14 12:37:12 by bitRAKE
I suppose I just want a new toy to play with.

Bazik, very cool, mind my asking how much?
Posted on 2003-07-14 19:01:23 by Eóin
A 64bit address space would be nifty, though not really _necessary_. To the end user, I think it will take some time before a 64bit address space would make a difference, but to us programmers it would make the use of eg memory mapped files a lot easier. Sure, MMF are slower than block processing with current CPUs, but some code is just so much easier to write if you can pass it a pointer instead of doing block processing :)

For end-user boxes, I'd rather have seen a clean well-designed from-scratch system (CPU, chipset, bus - harddrive technology could be kept though) than 64bit systems and crappy "let's continue hacking onto x86 like intel have been doing all the time" hybrids.
Posted on 2003-07-15 04:35:50 by f0dder