Stompy

I'm looking at some Athlon 64's and I noticed that the FSB says "Integrated into chip" and that the mobos actually have the FSB speeds on them.

One board had a 1.6ghz FSB while the others had 800 mhz w/ hyper transport. Isn't hyper transport the same as the hyper threading in the P4s? If so, then it's pretty much a trade off about whether or not you want a dual-CPU-like system or a single CPU one with an outstanding FSB?

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Aerundel

Hypertransport is not hyperthreading.

http://www.amd.com/us-en/Processors/...2_2353,00.html

Stompy

Ah ok. Someone told me it was, but I probably misheard them.

I take it the mobos w/ 1.6ghz FSBs are the way to go then?

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Lasereth

The "true FSB" on the processors are still 200 MHz though, just like HT P4's and the later Athlon XP chips. It may have a 1.6 GHz FSB, but take a look at the Pentium 4 HT -- 800 MHz. The later Athlon XP's have a FSB of 400 MHz, the P4's have a FSB of 800 MHz, and the Athlon 64's have a FSB of 1.6 GHz, but they're ALL running at 200 MHz true FSB. Just check it out in BIOS.

-Lasereth

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Stompy

Well, what I'm wondering is why the mobos have the FSB listed instead of the CPU itself (unless I'm misunderstanding this).

Typically when I look at a CPU I take note of the FSB, however, on the Athlon 64s, the only thing is "Integrated on chip".

I don't get why they have 800 Mhz boards for $100+ while the same exact company has a cheaper board that's 1.6 Ghz for $80. Is there a reason to buy the 800 over the 1.6?

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Lasereth

When it all comes down to the basics, every processor on the market has a true FSB and a multiplier. The true FSB is what you need to look at, not the FSB after the multiplier is added. Here's a breakdown of true/market FSB for Intel and AMD:

<UL>Intel Pentium 4 Processors
<LI>4x100 MHz true FSB = 400 MHz FSB
<LI>4x133 MHz true FSB = 533 MHz FSB
<LI>4x200 MHz true FSB = 800 MHz FSB
</UL>

See? The multiplier on Intel Pentium 4's is 4. The true FSB is multiplied by four, theoretically raising the market FSB to numbers like 800 MHz.

<UL>AMD Athlon XP Processors
<LI>2x133 MHz true FSB = 266 MHz FSB
<LI>2x166 MHz true FSB = 333 MHz FSB
<LI>2x200 MHz true FSB = 400 MHz FSB
</UL>

As you can see, AMD Athlon XP processors have a multiplier of 2 on the processor. The true FSB of the Athlon XPs are the same as Intel Pentium 4s...Intel simply jumped from 133 MHz to 200 MHz.

<UL>AMD Athlon 64 Processors
<LI>???x200 MHz true FSB = 1.6 GHz
</UL>

The Athlon 64 processors have an odd FSB. There is no multiplier, but theoretically it should be 8. 8x200 = 1600.

Every processor on the market shares a true FSB with a higher clock speed processor. A 333 MHz FSB Athlon XP has a higher FSB than a 533 MHz FSB Pentium 4. The Athlon XP's true FSB is 166 while the Pentium 4's is 133. It's all in the multiplier...the FSB listed on processors is basically for marketing. The true FSB is all buyers need to be aware of.

The FSB supported on the motherboard is a good fact to know, but knowing which socket the motherboard is is a bigger deal. The 1.6 GHz FSB motherboard will only take Athlon 64's and the 800 MHz FSB motherboard will only take Pentium 4's. Of course, both share the same true FSB. I hope this helps.

-Lasereth

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Stompy

Thanks a ton, that did help!

Both of the mobos I was looking at were Athlon 64 boards.

This one has the 800 Mhz FSB listing: http://www.newegg.com/app/ViewProduc...180-061&depa=0

While this one has the 1.6 Ghz FSB: http://www.newegg.com/app/ViewProduc...180-056&depa=0

Same socket and everything, but it's peculiar that one is double than that of the other.

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Aerundel

I'd go with the nForce3, personally. It looks to me that the 800/1600 difference is just marketing, since they should have the same FSB since they use the same proc (and they haven't had upgraded cores like some Intel procs that are 400/533 FSB). And according to this tech doc, http://www.amd.com/us-en/assets/cont...docs/24659.PDF , there is no difference.

Lasereth

He's right. It's just marketing BS...either motherboard will work.

-Lasereth

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Stompy

Thanks for all the info!

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