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PostPosted: Mon Jan 15, 2007 12:35 am    Post subject: Core 2 Duo: amd64 vs x86 Reply with quote

Whats better to use performance wise and stablity wise: amd64 or x86. I've seen some people chose both routes and I'm courious as to why. Are there certain major programs that just don't work well under the amd64?
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PostPosted: Mon Jan 15, 2007 1:02 am    Post subject: Reply with quote

AMD64 has a lot of problems, the only benefit I have ever seen about using AMD64 is the higher memory cap. I haven't actually heard of any other real benefits of amd64. Alot of programs that work on x86 won't work on AMD64. If I am completely off base someone correct me.
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PostPosted: Mon Jan 15, 2007 1:15 am    Post subject: Reply with quote

kraix wrote:
AMD64 has a lot of problems, the only benefit I have ever seen about using AMD64 is the higher memory cap. I haven't actually heard of any other real benefits of amd64. Alot of programs that work on x86 won't work on AMD64. If I am completely off base someone correct me.


I have never had any problems with amd64. as long as IA32 compatibility is in the kernel, and you've got the libraries, you can always run an x86 compiled app. this is my way of getting flash, I use a 32bit firefox, with flash plugin strait from adobe. there are other ways though...

this article was a quick find, and might also be some source of motivation : http://www.pcstats.com/articleview.cfm?articleid=1665&page=9

I just couldn't stand running plain old x86, when amd64 is one of the few improvements to x86 in a long time. god knows it needed it.

also, installing firefox-bin, mplayer-bin, win32codecs, and netscape-flash works just fine, and will give you a quick set of 32bit apps for your proprietary plugin media.
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PostPosted: Mon Jan 15, 2007 2:14 am    Post subject: Reply with quote

I guess I should have stated more clearly, alot of amd64 apps aren't as up to date as the x86 apps. I meant the actual amd64 apps not the x86 apps run on an amd64 core. And I haven't actually seen anything suggesting that amd64 is really any better than x86 performance wise. Has anyone seen anything suggesting this? Other than memory capabilities obviously. I have seen some apps keyworded ~amd64 and the same app is keyworded x86.
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PostPosted: Mon Jan 15, 2007 2:57 am    Post subject: Re: Core 2 Duo: amd64 vs x86 Reply with quote

Fire Hazard wrote:
Whats better to use performance wise and stablity wise: amd64 or x86. I've seen some people chose both routes and I'm courious as to why. Are there certain major programs that just don't work well under the amd64?


There are several posts speaking about this same issue.

Basically, for the end user the final result makes not a big different nowadays, except for a few programs that have been specially optimized to make use of the whole amd64 instruction set. Why do people migrate? Well, some might thing that it is cool, others think that without that step we would be asking to live on x86 for another 30 years. I mean, in the msdos/win3.x times everyone was happy running 16 bits applications, and many had that same question: why bother with things like win32s or dos4gw? But without that beginning windows would still be 16 bits (I mean more 16bits than already is hehehe ;) ). The leaps needs to be done at some point. I remember when we started using amd64 in gentoo. By that times to use amd64 was a real adventure, and lots of problems arised, mainly due to not-so-clean-nor-portable code hehe, but nowadays it is very rare to see a problem with amd64. While more and more programs are optimized at some point and the gcc compiler gets better on the (relatively) new architectures, the thing will improve.

Memory is also a concern. The linux kernel can handle more memory via some hacks, but of course, the performance can't compare to the performance of a memory model where all the indirections can be managed via hardware natively. So, some day we will need more ram as well. I remember having 8 mb simm and telling to myself "oh dude! I will never ever need more ram" (though I knew it was a false statement, cause I said the same with my 2 mb 386dx a couple of years ago). Gosh, people played Doom with 2 mb and my beast had 8 :P

Nowadays, we have totally transparent multilib management via portage, all the packages are set to compile correctly with no tweaking at all and the emul libs are already in portage, so no chroot is needed at all to compile them and install a multilib environment manually. All the thing is user transparent, and the 32 bits precompiled apps in portage works perfectly (well, as perfect as in x86). Sincerelly, it is nearly impossible to face an amd64 specific issue, at least, it is no more probable that facing an x86 specific one.

So, for me the question is: why not?

Well, the answer would probably be: cos I wanna 64 bits java plugin :P
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PostPosted: Mon Jan 15, 2007 3:05 am    Post subject: Reply with quote

@Shickapooka800

So what programs do you use that show this improvement in performance? Does installion and booting up speeds increase? Because it almost seems like I would have a 64bit machine running 32bit programes. That seems more of a henderence to the system than an improvement. Can YOU actually tell the performance difference in the two at all?
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PostPosted: Mon Jan 15, 2007 6:48 am    Post subject: Reply with quote

Fire Hazard wrote:
@Shickapooka800

So what programs do you use that show this improvement in performance? Does installion and booting up speeds increase? Because it almost seems like I would have a 64bit machine running 32bit programes. That seems more of a henderence to the system than an improvement. Can YOU actually tell the performance difference in the two at all?


well no, I cannot tell the difference at all. my reasons for running amd64 on an amd64 machine are for simple fact that sticking to x86 installations just because its easier doesn't much help the whole consumer pc world move over to 64bit does it? in my opinion this little transition in the pc world is taking way to long in the first place. it doesn't help that windows x64 blows and no one uses it, yet when the world turns and looks at the open source community, there are still plenty users installing x86 just because its easier and amd64 is "not worth it"

thats why I run amd64.
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PostPosted: Mon Jan 15, 2007 3:23 pm    Post subject: Reply with quote

I see your point. Long as you don't notice a decline in performance it would be best to use 64bit to help move software forward.

Thanks everybody for your input in helping me chose.
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PostPosted: Tue Jan 16, 2007 2:43 am    Post subject: Reply with quote

64 vs. 32 is a rather annoying argument. The extra 32 bits doesn't do anything other then open up a few more spaces to define some crap in in code (which can be circumvented if my memory servers me here).

Personally, I'd look at the cost vs. the speed vs. heat vs. power consumption. AMD has a few chips that take less power then Intels, but that is at a lower speed (but with Linux's CPU throttling, that is a lesser concern I would think). Intel with the Core 2 Extreme has taken the cake when it comes to speed, but thats not a cheap chip. AMD also has better cooling from what I remember, but I think the new Core 2 series has gone to a much cooler system as opposed to the P4-based chips.

Of course, nothing beat old fashioned research.
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PostPosted: Tue Jan 16, 2007 3:11 am    Post subject: Reply with quote

Dralnu wrote:
64 vs. 32 is a rather annoying argument. The extra 32 bits doesn't do anything other then open up a few more spaces to define some crap in in code (which can be circumvented if my memory servers me here).

Personally, I'd look at the cost vs. the speed vs. heat vs. power consumption. AMD has a few chips that take less power then Intels, but that is at a lower speed (but with Linux's CPU throttling, that is a lesser concern I would think). Intel with the Core 2 Extreme has taken the cake when it comes to speed, but thats not a cheap chip. AMD also has better cooling from what I remember, but I think the new Core 2 series has gone to a much cooler system as opposed to the P4-based chips.

Of course, nothing beat old fashioned research.


AMD's chips are still using the same three year-old architecture that was designed to counter Intel's NetBurst. It would be a shame for Intel's Core architecture not to be better in most areas than AMD64.
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PostPosted: Tue Jan 16, 2007 4:11 am    Post subject: Reply with quote

If you got the money, I'd look into Core 2 Extremes. Dual-cores are so 2005
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PostPosted: Tue Jan 16, 2007 9:01 am    Post subject: Reply with quote

I'd buy E6300/E6400 or even something from E4000 series. I have a E6400 (stock 2,13GHz) running at 3GHz beating anything on sale at stock speeds. I'm using a silent air cooling and my temps are quite lowish (always below 55 degrees C). Just see this:

http://www.tomshardware.com/2007/01/11/core-2-duo-overtakes-core-2-extreme/page12.html

Even the new 65nm AMD processors are no match to C2Ds at this point. But in spite of them being produced at 65nm they sill use the same old architecture:

http://www.tomshardware.com/2007/01/08/can-amds-65-nm-core-fight-back/page11.html

I also want to say that I have not had any problems with my x86_64 installation. Works just fine. I don't know what kraix meant by saying that "lot of amd64 apps aren't as up to date as the x86 apps".
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PostPosted: Tue Jan 16, 2007 1:34 pm    Post subject: Reply with quote

Paapaa wrote:
I'd buy E6300/E6400 or even something from E4000 series. [...]
I also want to say that I have not had any problems with my x86_64 installation. Works just fine. I don't know what kraix meant by saying that "lot of amd64 apps aren't as up to date as the x86 apps".


The core duos work well in a amd64 system?
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PostPosted: Tue Jan 16, 2007 2:01 pm    Post subject: Reply with quote

joaopft wrote:
Paapaa wrote:
I'd buy E6300/E6400 or even something from E4000 series. [...]
I also want to say that I have not had any problems with my x86_64 installation. Works just fine. I don't know what kraix meant by saying that "lot of amd64 apps aren't as up to date as the x86 apps".


The core duos work well in a amd64 system?


Sorry, I don't understand your question - "system" can mean so many things. But my core 2 duo works with with Gentoo AMD64 installation if that is what you meant? AMD64 is just a project name and doesn't reflect the fact that Intel's EM64T is equally supported.

There must be more than one user who thinks that you need AMD to use 64bit Gentoo... They really should change the name.
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PostPosted: Tue Jan 16, 2007 2:36 pm    Post subject: Reply with quote

Quote:
If you got the money, I'd look into Core 2 Extremes. Dual-cores are so 2005


Yeah I don't have a GAND to blow on a processor 8O. I'm still waiting on my loan money for school before I can by my "2005" Dual-core.
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PostPosted: Tue Jan 16, 2007 4:23 pm    Post subject: Reply with quote

I am running core2duo in my laptop, and I love the setup. It is a full 64bit Gentoo system, mplayer, firefox everything is 64bit (well everything that can be compiled). I use the nspluginwrapper for the plugins in firefox, the only thing I don't have is a java applet. For mplayer I use the 64bit compiled with ffmpeg and I can view all windows codecs movies just fine.

I am really happy with the 64bit efforts in gentoo. I am use the emulation libraries instead of a chroot and everything works without any problems. The initial setup was confusing b/c of all the options, but once you get going I don't even have to think about it anymore. There is a small performance benefit to using 64bit, and it is cool to say you use it, but it can cause some hassles down the road. I carry a 32bit firefox-bin just in case, but I haven't used it since I installed it.

Just my .2 cents.
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PostPosted: Tue Jan 16, 2007 4:54 pm    Post subject: Reply with quote

Paapaa wrote:
Sorry, I don't understand your question - "system" can mean so many things. But my core 2 duo works with with Gentoo AMD64 installation if that is what you meant? AMD64 is just a project name and doesn't reflect the fact that Intel's EM64T is equally supported. There must be more than one user who thinks that you need AMD to use 64bit Gentoo... They really should change the name.


I meant: 'the operating system distributed by Gentoo Linux, compiled with CHOST="x86_64-pc-linux-gnu"' :wink:

AMD64 is known as the name of a microprocessor arch:

"x86-64 is a 64-bit microprocessor architecture and corresponding instruction set; it is a superset of the Intel x86 architecture, which it natively supports. It was designed by Advanced Micro Devices (AMD), who have since renamed it AMD64. This architecture has also been adopted by Intel under the name Intel 64 (formerly known as EM64T, IA-32e, Clackamas Technology (CT) in reverse order). The names x86-64 or x64 are sometimes used as vendor-neutral terms to collectively refer to the two nearly identical implementations." (quoted from a neutral source -- wikipedia).

Only AMD can decide if it keeps the name; after all, it was the original designer! At the time, Intel was busy developing it's own 64 bit arch: IA64, which was a much more radical departure from IA32 than AMD64 is. But the first IA64 implementation (Itanium) had poor performance in IA32 compatibility mode. Because of that, the Itanium was not doing well in the server market against the Opteron. Then, to quickly gain sales volume, AMD rapidly pushed AMD64 into the desktop market (Athlon 64), while Intel was not in position to do that with its IA64 arch.

So Intel was forced to mothball IA64 and sell what the market was buying. EM64T is just a Intel's late (reverse engineered) version of AMD's x86-64 or AMD64. But Intel has done very little to promote EM64T.

Given that, my question remains: is EM64T just a quick hack, or has it been carefully implemented and shows merits of its own, when compared to the original AMD implementation? You say your E6400 is overclocked to 3.0 GHz. That's pretty impressive. I have my A64 X2 4200+ watercooled and it barely passes 2.7GHz. Does a gentoo x86_64 system run 100% stable @3.0GHz on your box? How do exec times for mprime compare in a 32 and 64 bit system?

I am asking this because I am thinking of putting together an E6400 box, but I need to know if it will make a much faster x86_64 system than what I have now.
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PostPosted: Tue Jan 16, 2007 5:03 pm    Post subject: Reply with quote

has anyone here tried to compile normal 32 byte apps with the -m64 CFLAG? Since that should tell the compiler to compile the code for a 64 bit enviroment, it might help with some compatability issues...
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PostPosted: Tue Jan 16, 2007 5:55 pm    Post subject: Reply with quote

joaopft wrote:

So Intel was forced to mothball IA64 and sell what the market was buying. EM64T is just a Intel's late (reverse engineered) version of AMD's x86-64 or AMD64. But Intel has done very little to promote EM64T.

Given that, my question remains: is EM64T just a quick hack, or has it been carefully implemented and shows merits of its own, when compared to the original AMD implementation?


Hack or not? I think that is irrelevant. Whenever AMD or Intel comes up with a new instruction set the other one has to copy it: MMX, SSE, 3DNow etc. It is impossible to tell if it is a quick hack or not but C2D processors really work perfectly in AMD64 installation as the instruction sets are basically 100% compatible.

joaopft wrote:
You say your E6400 is overclocked to 3.0 GHz. That's pretty impressive. I have my A64 X2 4200+ watercooled and it barely passes 2.7GHz. Does a gentoo x86_64 system run 100% stable @3.0GHz on your box? How do exec times for mprime compare in a 32 and 64 bit system?

I am asking this because I am thinking of putting together an E6400 box, but I need to know if it will make a much faster x86_64 system than what I have now.


Of course it is 100% stable (I would not run an unstable system). 3GHz is not that impressive. 3,6GHz should be possile even with air cooling. My processor is also on air and the temps are always below 55 degrees C in full load. I have also undervolted my processor to 1.235V as opposed to stock 1.325. Now my case is open, I'm running Orthos and my load temp is 47 degrees. So yes, it is cool and no watercooling is needed at all. My idle temp is now (case open) 38 degrees C. This is measured from the on die DTS using CoreTemp (Windows program...).
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PostPosted: Tue Jan 16, 2007 7:10 pm    Post subject: Reply with quote

Paapaa wrote:
3GHz is not that impressive. 3,6GHz should be possile even with air cooling. My processor is also on air and the temps are always below 55 degrees C in full load. I have also undervolted my processor to 1.235V as opposed to stock 1.325. Now my case is open, I'm running Orthos and my load temp is 47 degrees. So yes, it is cool and no watercooling is needed at all. My idle temp is now (case open) 38 degrees C. This is measured from the on die DTS using CoreTemp (Windows program...).


That is impressive. I am a little disappointed with double core Athlon 64's, right now they are poor overclockers when compared to the Core 2's. Intel has never messed up in fab process, no doubt about it.
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PostPosted: Wed Jan 17, 2007 12:05 am    Post subject: Reply with quote

A big weakness I notice on x86, as compared to amd64, is the x87 FPU, which is limited and slow as hell. Of course, in current processors, one can use SSE instructions for FP calculations: force that by using gcc flag -mfpmath=sse. However, note that this may break x86 code that expects 80 bit sized FP numbers.

So on amd64 -mfpmath=sse is enabled by default, whereas on x86 -mfpmath=386 is enabled by default. If you compile and run numerical computation software, amd64 is a better choice. There are also other features like having more registers, that make it simpler for the compiler to produce optimized code. For example, the compiler can make use of a lot more register variables simultaneously, and that may be useful in heavily nested loops. This produces highly optimized code, both in terms of speed and size (no need for unrolled loops). This means that on amd64 the gcc flag -O3 almost never improves exec speed over -O2. This alone may save some compile time.
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PostPosted: Wed Jan 17, 2007 12:22 am    Post subject: Reply with quote

What would be interesting to mess with would be trying to run dual CPUs (or a specially crafted dual/quad core chip) to use the diffrent CPUs for what they work best at. Since it seems C2D's beat AMD in pretty much all aspects minus math, then using an AMD chip to deal with the math while the Intel chip handles the more basic system work could be interesting.

Of course, I would hate to mess with the design work for such a mobo/chip...
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PostPosted: Wed Jan 17, 2007 1:00 am    Post subject: Reply with quote

Dralnu wrote:
has anyone here tried to compile normal 32 byte apps with the -m64 CFLAG? Since that should tell the compiler to compile the code for a 64 bit enviroment, it might help with some compatability issues...

What compatibilty issues? I haven't run into a single problem with any of the 600+ packages on my C2D amd64 system.

And -m64 is a bad idea to ever put in CFLAGS. I'm fairly certain at least one Gentoo dev pointed this out to you in another thread... It can easily break the whole system.
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PostPosted: Wed Jan 17, 2007 1:43 am    Post subject: Reply with quote

broken_chaos wrote:
Dralnu wrote:
has anyone here tried to compile normal 32 byte apps with the -m64 CFLAG? Since that should tell the compiler to compile the code for a 64 bit enviroment, it might help with some compatability issues...

What compatibilty issues? I haven't run into a single problem with any of the 600+ packages on my C2D amd64 system.

And -m64 is a bad idea to ever put in CFLAGS. I'm fairly certain at least one Gentoo dev pointed this out to you in another thread... It can easily break the whole system.


I think they were pointing out the uselessness of -m32 on a standard x86 system. If they said otherwise, then apparently I either forgot, or had already fixed the problem and didn't pay much attention.
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