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Windows Vista 64bit, AMD X2 or C2D?

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Any thoughts, or reviews you guys know about, around AMD X2 vs. Core 2 Duo while in Windows Vista 64bit?

What CPU will be better while in 64bit OS?

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Only comparison I know was done by X-bit Labs.

The average performance improvement we have seen from Athlon 64 FX-62 equaled 16%, while Core 2 Extreme X6800 demonstrated only 10% average performance boost. This way, there is a certain difference: AMD K8 turns out 6% mode efficient in 64-bit mode than Intel Core. However, this difference cannot compensate for the 20% performance advantage of the Intel Core 2 Duo over the Athlon 64 X2 working at the same clock speed, which we have pointed out in our previous articles. Therefore, we will not change our conclusions about the performance of the new Intel processors even keeping in mind the upcoming launch of 64-bit Windows Vista OS family.
http://www.xbitlabs.com/articles/cpu/displ...uo-64bit_7.html

Now take into account that very affordably priced Conroes can be easily overclocked even further than speed of X6800 and choise is very clear.

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When comparing four-core systems, Vista will give a huge speed boost to AMD's '4x4' platform (a high-end desktop two-socket platform.) This is because Vista properly supports NUMA, which is what AMD's multi-socket systems use.

Although it should only boost speed to what it SHOULD be in the first place. Again, this won't have a 4x4 system beat Core 2 Quad, it will just allow 4x4 to use its full speed.

*NUMA stands for "Non-Unified Memory Architecture", meaning each processor socket has its own set of memory. When a piece of information is in the memory for socket A, and a processor in socket B wants it, it has to pass through the socket A processor. When the OS knows about this, it can cache things better. When the OS doesn't know about it, the memory controllers have to do all the work, which is inefficient. Because all AMD processors have onboard memory controllers, if you have more than one socket, you have multiple memory controllers. On Intel systems, even multiple socket systems, there is one memory controller for all sockets. This means that on a massively-parallel system, AMD's system would probably be better, but even up to 4 sockets, a single memory controller will probably do better. (So AMD really should start sponsoring more supercomputing matrices.)

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I am a bit pusseled... why isn't AMD 64 doing any better in 64bit OS? "Everyone" touts that AMD's 64bit implementation is better and more thorough than Intel's...

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I am a bit pusseled... why isn't AMD 64 doing any better in 64bit OS? "Everyone" touts that AMD's 64bit implementation is better and more thorough than Intel's...

I've heard the same. A friend of mine testing platforms for a capacity planning whitepaper told me that AMD's 64-bit implementations are a hair more efficient but nowhere nearly enough to overcome the sheer computing power that Intel is currently bringing to the table. He says that Vista just flies on a quad-core system--so much so that he feels a quad-core business desktop with a decent amount of RAM would have a 5-year shelf-life (standardized) in business environments if built with quality componentry.

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I am a bit pusseled... why isn't AMD 64 doing any better in 64bit OS? "Everyone" touts that AMD's 64bit implementation is better and more thorough than Intel's...

Well, AMD and Intel are still using (almost) identical x64 instruction sets, so it's not like a 64bit OS can call faster different instructions on AMD than Intel. phoenix and ehurtley are right that AMD does have better/faster access to memory which did make it few percent faster than Intel... it's just todays Intel dual/quad-core "Core" CPUs are so significantly faster in raw CPU speed that they more than make up for any loss in memory speed.

NUMA just lets the OS know that not all memory is the same... that some is faster for a particular CPU than the rest... so the OS can be smart about keeping the memory for a process and the processor its running on together. But this buys you the most speed if you're using apps that constantly use large chunks of memory... which isn't something most desktop apps do. Like ehurtley says, it's more of a win for supercomputers, grids, and scientific/financial computing than for the average home user browsing the web and playing games.

I've used only AMD for many many years now, since it was the best bang-per-buck. But if I had to buy a new system today I wouldn't hesitate to buy a dual/quad-core "Core" CPU from Intel... since it's faster for the money, has good headroom for overclocking, and is just an overall better value.

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Well, AMD and Intel are still using (almost) identical x64 instruction sets, so it's not like a 64bit OS can call faster different instructions on AMD than Intel.
Quoted for emphasis. AMD64 may be better than Intel EMT64, but the differences are trivial at best, including performance differences.

Throw in the fact that the Core microarchitecture has a definite clock-for-clock perofrmance advantage over the K8 architecture (be it at 90nm or at 65nm), and that both can hit similar clock speeds, and for the moment Core 2 Duo is the chip to have at the moment. The release of K8L in a few quarters may change that, but if you need to buy now...

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