So many options these days and probably lots of them I don't need. So some questions:

Is 64bit software feel twice as fast then 32bit software? Or does that do with multitasking?

Having (for example) a dual core 2.6GHz vs a quad core 2.3GHz... what would you feel? If I'm looking for speed instead of multitasking, would it be better to get option A?

And ahh, think that's it...

Sadly, nothing. I have a dual core AMD notebook, and I don't notice much of anything while running XP, but thats also because XP is 32bit, even though my processor is 64-bit, but also running applications like firefox, thunderbird, even snes, genesis emulators, there is no change, mainly because most of the programs you encounter are NOT even optomized for SMP (symetrical processing), let alone 64-bits. Although the transition has begun, I can't name a lot of software that utilize both cores or quad, except for windows itself, but as far as other programs within the OS, I couldn't tell you, so it would be best just to go with the dual core, but also I have seen that windows XP can support up to 50 some processors at once. I have seen this by pulling up the task manager, clicking on the process, and setting it's affinity, and you are presented with a box, with up to 50 processors, but if you are running dual or quad, then only up to 2 or 4 boxes are actually active, rest are inactive, and cannot even be set.

As for the option, 2.6 and 2.3 isn't that much different, it is just different by 300Mhz, and for your everyday stuff, there won't be any noticeable change, unless you are going to work in higher end stuff, like graphics, media processing (video encoding), and gaming.

How about comparing the x6800 to the 965?

Differences I see:

The 965 is 800Mhz faster, and has HyperThreading.

Cores are to do with multitasking, which can be done fine w/ a dual core. W/ that out they way, it's down to clock speed, faster's always better so the Intel Pentium Extreme Edition 965 actually be the best.

Nevermind, I answered my own question.

I have nothing to say except my PC is the best one in this thread, bloody brilliant

I have some input. I have an Intel QX6600 Quad core overclocked to 2.6GHz. I originally installed Ubuntu 32-bit and ran a matrices test (not a multithreaded application). I then ran 4 different matrices on each CPU and overloaded the system.

I then reinstalled Ubuntu 64-bit and ran the same 4 matrices. The speed improvement on each single process was not faster, but overall on an average, it came out quicker. So in my early experience, the 64-bit seems to handle the loads better.

Yea right. Micro420 already has you far outstripped and thats just the people we know about it.
Everyone else here probably has a Tyan motherboard loaded up with 4 overclocked dual-core opterons and 16 gb of ram.

Ahh to have such a system ...

I have a question: If I had that processor, would I have 4 2.6 GHz processors stuck together or is it 2.6 GHz in total?

If you can indeed see, I have posted before him in this thread and i ain't a nut head to edit it now, so keep reading..!!

Yea, I think I noticed that.. and did'nt really care. Does'nt really matter what order you posted in. You can split hairs here if you like, your computer is still inferior. So...

LOL!! ...err...
... not really, "clock speed is not everything", look for that quote thought that link and read carefully

Each core runs at 2.6 GHz, which obviously doesn't mean to have one big core running at 10.4 GHz (2.6 * 4)

For such a system to be busy, I can imagine that it should be running a big database (1+ TB) and several services, over a network crowded with lots of users; or maybe several 3D rendering applications with complex pathfinding algorithms; or some scientific application that can put the machine on its knees. Otherwise it's wasting every watt of energy it consumes.

You are definitely correct. My academic institution that I work for has super computers set up for extreme testing, like testing nuclear warheads and physics stuff. I'm like a speck of dust compared to those guys!

I'm ignorant as to how many processors are listed when running the 64-bit kernel. Does "Core 2 Duo" function as 1x64 bit processor -or- 2x32 bit processors? [That's a horribly-worded Yes/No question.] Meaning, a quad-core functions as 2x64 bit?

And am I correct in understanding that everything runs fine using the SMP kernel?

... meaning a calculation node with 2 "quad" processors would appear as 4x64 bit processors, and all you have to do is install the 64 bit SMP kernel?

... and lastly, Micro420 - do you know if scientific code must utilize MPI to properly utilize every processor, or is it as easy as compiling 64-bit and letting the kernel take care of the rest? (I would PM you but I don't have privledges.. or something..)

Hope this question isn't too ign'ant

I now have an E6600 Core 2 Duo overclocked to 3.2 GHz, 2 MSI nVidia 7950GTs in an SLI configuration, 1TB RAID 0+1, dual Gigahertz NICs - and a Thermaltake aluminum case with tons of fans. The thing is blindingly fast. 3D Benchmark score of 6,383. Not the fastest box around, but light years ahead of anything I've had before.

The 965 Pentium Extreme Edition is a hyperthread processor making two CPU cores appear to be four CPUs. Each core has a 2MB L2 Cache. The Core 2 Duo is two actual 64-bit processors on the same die (likewise the quad being 4 actual 64-bit processors on the same die). There is a single 4MB L2 Cache. The Conroe chip appears to be faster - even when not overclocked.

Either way, these things are great on computationally intensive tasks - like gaming

Yes, you must code and program to utilize MPI for the specific program you are using. The kernel does not work magically by itself to split processes to each CPU, unfortunately.