AGP speed

[-lynx-]

Can someone please clarify this for me:

FSB 100MHz (default on many modern mobos) - AGP is running at 66MHz, right?

FSB 133MHz - AGP will run at what, 88MHz?

Or is the AGP clock normally ticking at the FSB frequency?

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-lynx-
13 Sqn RAF

[MANDOBLE]

Afaik, with modern MB you can set the AGP speed multiplier factor to 66x1, 66x2 or 66x4, independently of the FSB frequency selected. For example, I'm actually running 133 FSB with AGPx4. The AGP multiplier factor is usually changed via the bios menu.
Some older motherboards have an option to run the FSB at same frequency than AGP.

[Bombjack]

Hi Lynx  

What AGP dividers are available depends on your motherboard. Only the new VIA's and the Intel 815/820/840 support a 1/2 divider. BX boards don't divide lower than 2/3.

Hence if you run at 133FSB on a BX board your AGP slot is at 89MHz, way out of spec. Whether your video card will work at that speed is dependent on the card and the motherboard. My CL Annihilator Pro and BE6-ii do work, luckily.

As a slight bonus the faster AGP bus speeds up transfers a little, giving an increase in texture/instruction throughput, all else being equal.

[-lynx-]

Aha - so, the AGP normally runs at FSB frequency... Hmmm... Since 600E's aren't available anymore I guess I'm stuck with my 450... 4.5x133... 598... Hmmmm... The V770 Ultra had better keep clicking at 89MHz or there's gonna be trouble .

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-lynx-
13 Sqn RAF

[Bombjack]

Unfortunately there's almost zero chance of getting an Intel 450 MHz chip (P2 or P3) to 133FSB. They were built on a .25 micron process that was pretty much at its limit when the 450s were made (Intel finally got to 550 MHz with extreme difficulty).

Are you sure the 600e's not available? I hadn't heard it was gone yet. That's the processor I bought, now running at 800 MHz very nicely. Under no circumstances get an EB though  

[-lynx-]

Err.. It booted last time I tried (PIII450).

As for 600s I've checked both Insight and Dabs - largest UK suppliers - they're out. There's a possibility that a small supplier might have a few stuck in stock but it's unlikely. I think Intel is getting ready for the next generation release and making sure that no smart tulips will laugh in their faces with over-clocking older chips rather than buying the newer ones.

My work Dell is PIII600, but it's 1998 chip - can't be an "E", can it? - otherwise I'd have swopped it with a Celery 333 I have lying at home gathering dust .


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-lynx-
13 Sqn RAF

[Bombjack]

You might try these guys:
 http://www.pcupgrader.com

[NUTTZ]

 

Originally posted by -lynx-:
Aha - so, the AGP normally runs at FSB frequency... Hmmm... Since 600E's aren't available anymore I guess I'm stuck with my 450... 4.5x133... 598... Hmmmm... The V770 Ultra had better keep clicking at 89MHz or there's gonna be trouble  .

600's are aplenty at all the shows i go to..
NUTTZ