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64bit hardware question - Core 2 Duo/Itanium differences

Instead of posting my specific software problem, I thought I would try to get a better understanding of 64bit enabled hardware. We are experiencing a problem with some of our new Core 2 Duo machines and I thought I would go down this road a little while to see where it leads in solving my problem. My understanding is that the latest Intel Core Microarchitecture processors (Merom, Penryn, Allendale, Conroe, Wolfdale, etc) are 64bit in their architecture...where as the older Pentium 4's, Original Core Duo chips, etc, are only 32bit. Is this correct, and if so, what makes the Intel Itanium chips different than the latest Core 2 Duo's? Obviously, the latest Core 2 Duo's run 32bit Windows just fine, and I would guess that most of the computers in the world are still running 32bit OS's, even though the hardware claims it's 64bit capable (I even remember a few years back that many AMD laptops had AMD 64 processors but we only ran 32bit Windows on it!). Anyway, maybe the Itanium processors can't run 32bit apps, but the latest Core 2 Duo's can run both, hence making them a better choice than the Itaniums???

Back to the point of my question (which is really a confusion about 64bit and 32bit hardware), in trying to troubleshoot my particular problem, I am thinking that maybe the cause of the problem is that our older software application is having a hard time running on the latest Core 2 Duo hardware as it runs just fine on our P4's, Pentium D's and Pentium M systems. The problem is that our latest Core 2 Duo systems are locking up and hanging when we run our particular software tool and I am not sure why. I figured I would look into the 32bit vs. 64bit hardware as the potential problem, but I first need to understand the difference between the various Intel chips.

By the way, am I the only one who is TOTALLY confused by Intel and their "Core", "Duo", "Dual Core", "Pentium Dual Core" naming conventions? Why are there SO many variations of it??? Then they throw in these crazy names like "Conroe", "Yonah", "Allendale", etc. Why can't they distinguish their lines of processors better??? Sorry, just had to get that off my chest.

jbobst

ASKER

After reading my question, I realized it is phrased very poorly...it's just that I am not exactly sure what I am asking. Let me just clearly describe my problem: We have a software application our software engineers use called "Matlab". We have not kept up with the latest version and have a very old version of the Matlab software. The problem is, when our engineers run a certain task with Matlab on our newest Core 2 Duo systems, they lock up every time with this particular thing. Yet, we have a bunch of P4's with hyper-threading, a bunch of Pentium D's and a few older machines that never lock up when we run this task. Since our latest PC's are running the Merom and Allendale Core 2 Duo's, and this seems to be the main difference, I figured something with these newer processors must not like our old version of Matlab, and must be causing the software to hang. I figured that if the architecture of these newer systems were based on 64bit computing (even though we are running Windows XP 32 bit exclusively on ALL our systems), maybe that was the cause of the problem. However, I am not sure I understand the true differences between a Pentium D and a Core 2 Duo for example...other than one is 64bit enabled and the other isn't. Hope that clears it up a bit.

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aloyd18

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Callandor

Itanium chips don't use the x86 architecture, which is why they can't run 32-bit apps. They use EPIC (Explicitly Parallel Instruction Computing) to run applications, and the software must be explicitly designed for Itanium. There are Pentium4 cpus that can handle 64-bit; they are identified by the EMT64 attribute and models like the 600 series has it. You can read more here: http://filesharingtalk.com/vb3/history/topic/123242-1.html

As to why your application has problems on the Core2 Duo and not the Pentium-D, that sounds very strange. Test it on a Pentium with EMT64 to see if 64-bit capability is involved. Otherwise, it may be that the application is not thread-safe.

jbobst

ASKER

Sorry, I was probably unclear... We don't have ANY computer running 64 bit operating systems or apps at this point. Every operating system and application is 32bit. I just was questioning whether or not the newer Core 2 Duo's were 64 bit in their architecture. It seems like they are advertised as 64bit enabled, but they all come shipped with 32bit Windows, so I assume they run both 32bit AND 64bit operating systems??? Where as, it seems like the Itanium processor only run 64bit? So, does that mean that the Core 2 Duo systems are somehow interpretting software differently? Meaning, it's 64bit hardware, downgrading to 32bit software?

jbobst

ASKER

Callendor,

So you are saying that Itanium chips are ONLY 64bit chips, where as some Pentiums and Core 2 Duo's are both 64bit and 32bit capable? If they are capable of both 32 and 64 bit, could this "translation" be effecting anything at the application level?

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Callandor

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jbobst

ASKER

Good stuff, thanks. There appears to be some sort of "problem" with Core 2 Duo's that I found in a microsoft article, so maybe this could be our problem. Anyone know about this particular issue?

http://support.microsoft.com/?kbid=936357

Also described a little here: http://en.wikipedia.org/wiki/Intel_Core_2#Chip_bugs

Callandor

It may be that Microsoft's patch will address your problem.

Apparently, TLB errors are present in AMD's latest Phenom chips as well: http://techreport.com/articles.x/13741