Louis Garcia wrote: There is NO advantage installing a 64 bit OS on a 32 bit CPU that has extended features to EMULATE AMD 64 bit instructions. Other than memory address space and a few other things that will never be warranted on today's laptops. Stick with 32 bit Fedora on all intel CPU platforms except itanic. You will be fine. Having said that, I would also propound that the opposite is true for AMD 64 bit CPU platforms. You can lose up to 15 percent (from my own personal tests) performance by running a 32 bit made for intel instruction set on AMD CPUs, because it has to EMULATE 32 bit instructions. That is one of the reasons I always cringe at benchmarks done in 32 bit MS Windows on multi CPU platforms comparing AMD vs intel. There are soooo many things wrong with that. :) Good luck with your new laptop. You can check recent posts, but the trouble areas may include: Wireless card -- Brodcom chipsets are just beginning to be supported. Multi Card reader with Ricoh chipset -- just got put into upstream kernel, and still lacks SD support. Display -- Fedora will probably NOT get the display right, but system-config-display, hardware tab, select LCD(resolution of display) as display type, then back to general tab to set resolution. GNOME defaults to suspend for everything. System/Preferences/More Preferences/Power management -- in every tab, change suspend to Do Nothing. Play with suspend outside of GNOME before turning these back on.

Tony Nelson wrote: Documentation is plentiful, but 'proof' does not exist for anything in this world. Lets just call it documentation. intel dead ended Pentium 4 due to heat and performance characteristics intel used the good heat and performance characteristics of the Pentium M (which is an evolution of the Pentium 3) and moved it to 65nm process. In order to obfuscate the origins of the processor, the Pentium name was dropped altogether and a new marketing series was developed for the newest evolution of the Pentium 3 called Core. You might recall that the Pentium 3, as well as the Pentium M are 32bit. You may also recall the years spent developing Itanium, a true 64bit platform. How long in development from the EOF of Pentium 4 and the release of the 'Core' CPUs? So please, lets examine how intel gets 64bit instructions to run on what is essentially a Pentium M architecture. ASSUMPTIONS: There are still some bright folks at intel. intel is marketing driven, not market driven -- see: 'viiv' and 'centrino' Let's start our look here: http://arstechnica.com/articles/paedia/cpu/core.ars --- From the article: Intel's approach to multicore is not about keeping each individual core's on-die footprint down by throwing out dynamic execution hardware, but about keeping each core's power consumption down and its efficiency up. In this sense, Intel's strategy is fundamentally process-based, which is why I said it's "very 'Intel.'" Intel will rely not on the microarchitectural equivalent of a crash diet, but on Moore's Law to enable more cores to fit onto each die. It seems that from Intel's perspective, there's no need to start throwing hardware overboard in order to keep the core's size down, because core sizes will shrink as transistor sizes shrink. --- My Comment: This is the principle technical advantage that intel has over every other chip manufacturer. They can, do, and will shrink process faster than anyone. They will be shrinking again in 2007, at the relative 'same time' as AMD is just getting down to 65nm. --- From the article: Core's designers took everything that has already been proven to work and added more of it, along with a few new tricks and tweaks that extend some tried-and-true ideas into different areas. --- Now lets look at some of the documentation from intel. http://www.intel.com/technology/magazine/computing/core-architecture-0306... Please notice the complete lack of any and all marketing data calling this a 64bit architecture. And none here: http://www.intel.com/products/processor/coreduo/index.htm And no mention of any 64bit goodness anywhere here either: http://www.intel.com/products/processor/core2duo/index.htm But wait, there is a 'hint' here: http://www.intel.com/products/processor/core2duo/specifications.htm Following the 'hint' we get to here: http://www.intel.com/technology/64bitextensions/index.htm Now we are getting somewhere, right? Oops, no mention of laptops?? How does a consumer know if a new core 2 duo laptop is 64bit OS capable? And now, oh reader, I leave it to you to examine any and all of the intel reference documentation on that page to clarify this issue. The real question is: Does the addition of EM64T make this a 64bit platform? My conclusion: NO. And further, does every core CPU model feature EM64T, and how can you tell? If not, then what does EM64T on Core really mean? You decide.

Anderson Alipio wrote: Almost certainly a motherboard problem -- the ACPI tables are part of the BIOS, which is held on the motherboard. Try looking for an update. Or try apci=ht : this is documented to be the minimum necessary to get a Pentium 4 with hyperthreading to actually hyperthread, so it might get you running with two cores. Also try pci=noacpi and acpi=noirq. Hope this helps, James. -- E-mail: james@ | Things have never been the same since my arch enemy, due aprilcottage.co.uk | to a slight clerical error, put a price on my shed. | -- Jim

Tony Nelson wrote: You will please notice, Mr. Troll, that the original question was about Core 2 Duo. My 'claims' are: There are no benefits to running intel CPUs (other than Itanium) in 64bit mode. (other than extreme memory requirements which do not impact today's laptops) There are definite benefits to running AMD 64bit CPUs in 64bit mode. Since the original question was regarding intel CPUs, and since the AMD statements were an aside, lets focus on just intel Core 2 duo as the original author questioned. Lets take a look at some benchmark tests done by intel and submitted to SPEC. Lets also assume that all hardware vendors go to extreme measures to get the best performance numbers out of the systems being tested. Start with this one: http://www.spec.org/cpu2006/results/cpu2006.html Kindly notice that the best performer in the CINT2006 (26) section was intel Core Duo. Lets take a closer look: http://www.spec.org/cpu2006/results/res2006q3/cpu2006-20060904-00085.html Please scroll down far enough on that page to notice the Software section. What do we see here? That intel 'claims' that the best performance for Core 2 Duo is achieved in 32bit mode. Its hard to imagine what you might accept as 'proof'. However, for thinking persons it is not very difficult to discern that intel is not pushing the 64bitness of Core 2 Duo, despite the fact that 'viiv' requires it. Again, just for the fun of it, lets ask Dell, the largest purveyor of intel based platforms if it sells a Core 2 Duo laptop with Windows XP Professional x64 Edition. I come up with a blank. How about you?

Phil Meyer wrote: Not quite. There have been a *lot* of tweaks involved in producing the Core 2 core (and Intel's naming schemes are still awful...). It's similar to the amount of changes between the Athlon XP *core* and the Athlon 64 *core*. Itanium *is* a true 64 bit platform. It's also what's variously called "VLIW" or "EPIC". It is *massively* different from any of the other common CPUs out there. Intel was practically doing raw research while they were trying to produce their new processor. That's a lot different from widening datapaths and adding support for a few more architectural registers (which is basically what's needed for AMD64 support). There's nothing in the AMD64 instruction set that wasn't well understood twenty-five years ago (with the probable exception of stuff like SSE and MMX). I maintain that making a processor support AMD64 is a *lot* easier than making it fast by modern standards (which the Core 2 certainly is). Irrelevant, really. Once Intel had decided to support AMD64 (under whatever name), it was obvious that this would be wanted on laptops. So Intel would have wanted to get support on laptop chips sooner or later. It's not about whether the laptop can make use of more than 4 GB of memory -- it's that there are some pretty big organisations that would want to run the same binaries on laptops as on servers (which quite probably would be 64 bit), or the same binaries as on desktops (which are increasingly likely to be 64 bit). And those are the sort of accounts where Intel would like to keep AMD out. Why would laptops need to run server programs? Usually for demonstration, troubleshooting, or programming purposes. It can be very useful for field engineers to turn up on a site and be able to run their own copy of the customer's programs on their own laptop. Good article, but it doesn't help your cause. Marketing! Marketing, marketing, marketing! You've said it yourself! Intel is a marketing-oriented company! They'll deny the sky is blue if it suits their purpose! And it *does* suit their purpose. Given that Intel has poured billions of dollars into Itanium, given that one of the key marketing features was that it was 64 bit, why would Intel want to detract from that? Intel has a very clear separation in it's own corporate mind between the Itanium, Xeon, Pentium (and now Core) and Celeron brands, and the pricing reflects this. They do *not* want people who might buy a more expensive brand to think that a cheaper brand would be just as good. So they trumpeted 64 bits for Itanium, and kept quiet about it for EMT64. (Intel had hoped that people would transition to Itanium as they ran out of steam on 32 bit x86 -- making an AMD64-compatible processor scotched that hope, but it died hard). Incidentally, Intel are now talking about EMT64 at http://www.intel.com/technology/64bitextensions/ and calling it 64 bit computing -- their position has changed as 64 bit has become more prevalent. Then what does it *%£&*£* take to make a platform 64 bits? It runs Fedora 64 bit binaries. But this isn't what you set out to prove in the first place. *Not* that Core 2 couldn't run 64 bit binaries (it obviously can), but that Core 2 couldn't run 64 bit binaries *efficiently*. To do this, we would need documentation showing that the speedup or slowdown that Core 2 gets from running 64 bit binaries is significantly worse than the speedup or slowdown that an Athlon 64 gets. Did every AMD processor based on the Athlon 64 core feature AMD64? As a matter of fact, it didn't -- there were a number of Semprons based on Athlon 64, which needed the original Athlon 64 Socket 754 interface, which had AMD64 turned off -- it was initially reserved for the Athlon 64s and Opterons. AMD was taking a leaf out of Intel's book -- various Intel CPUs from the same family at the same time have had VT, Hyperthreading, EMT64, different bus speeds, dual core, and probably other features I've forgotten turned on or off as it suited Intel so they could aim processors at different markets (and try to make sure that someone who needed a particular feature was likely to pay more for it). Hope this helps, James. -- E-mail: james@ | A: Because people don't normally read bottom to top. aprilcottage.co.uk | Q: Why is top-posting such a bad thing? | A: Top-posting. | Q: What is the most annoying thing in e-mail and usenet?

On Mon, 2006-10-09 at 09:43 +0100, Nigel Wade wrote: I am not sure, but my mother board had some serious problems, so I had to replace it. I found the cheapest MoBo/CPU combo I could find, and ended up with an ASUS K8V-X SE MoBo and an AMD Sempron 2800+. My old mobo had a Celeron 2.4, but it was cheaper to buy a new MoBo and CPU than to get one that worked with the old CPU. I did not realize that the Sempron was 64 bit until I had the system back up and running and someone asked how well the 64 bit system was working, then I looked at the CPU box more carefully. I am still using the same kernel {kernel-2.6.17-1.2187_FC5} I was using with the old MoBo CPU combo, and this system is considerably faster that it used to be. I am extremely happy with the 32 bit performance, and since I only have 1GB of RAM I don't think I need the 64 bit memory support. In conclusion, whether or not 32 bit opcodes are emulated or native, the processor runs very well with a 32 bit kernel. As I need this computer for work I am not intending on trying any 64 bit tests, since the system is working well, and I can't afford for it to be down.