Athlon XP FSB underclocking

SplinTAH

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Hi. I currently have a motherboard that only supports 200fsb, and i don't really want to have to spend more money on buying a new motherboard (as i have only just bought this). And i was considering buying an Athlon XP for the board and editting it so i could make it run at 200fsb instead of 266. Any ideas? I have a Gigabyte GA-7IXE4

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tombance

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It could be done, ur CPU would run a lot cooler and you could set it to a lower voltage, although the performance would drop due to the slower bus and speed.

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Civilized

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A couple things to check out before you order this processor...1) I am not sure this motherboard will correctly recognize a xp processor. It will support the tbird line but im not sure about the xp? I checked online and it says nothing about it even in the bios revisions? i would look into this
2) I just looked up your motherboard on gigabytes website and the highest you can clock your processor would be 115mhz fsb (230 mhz external clock)...it supports settings of 90, 95, 100(your current processor), 105, 110, 115mhz and all of the fsb changes are made through dip switches on the motherboard...refer to your manual regarding this....
So you would be really cheating yourself buying this processor for such an old/aged motherboard...in other words you would be downclocking the speed of the processor since the multiplier is locked on these processor (if you can unlock the multiplier then maybe you could reach its true speed but with a much lower fsb)...my suggestion is to save up and upgrade the mobo as well...at least to the k7S5a (super super cheap mobo) from ecs which will support your ram and the processor to its fullest. My two cents
 

SplinTAH

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Well, i emailed AMD about the chip, and they said that it would work on the older motherboard. I know its kind of cheating, but even an underclocked Athlon Xp is better than a Duron?

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SplinTAH

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I'm now just waiting for ANOTHER email back from AMD to confirm that it will work. I think it should.. because my mate has run an XP 1800+ at below 100fsb before on an older board. I just need to save up £40 now lol

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bronibbear

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Be careful some older motherboards cannot run the XPs stably I ran into this prob myself! Then again this is not always the case and if AMD says its ok you're probably safe. If you can pick up a thunderbird 1.3gig or higher you'll probably have no probs even using a type C which run on a 266 FSB for although your motherboard only supports 200 FSB you can easily up the multiplier to compensate. All Thunderbird CPU's of this speed and higher are multiplier unlocked! If you get a Thoroughbred XP (not a Palomino as they are tricky to unlock) you might be able to get it up to a decent speed if your motherboard has high enough multiplier settings. However this chip must be physically unlocked by shorting one bridge on the chip.

check this site out on how to do this
http://www.overclockers.com.au/article.php?id=118669

Just did a bit more research on this method of unlocking and it may not be of benefit to you after all as it makes multipliers available below the CPU's default not above which you need. Could be useful though if you get a 266 or 333 FSB motherboard as it would allow you to pump your FSB up to very high settings with the lower multiplier settings enabled.


<P ID="edit"><FONT SIZE=-1><EM>Edited by bronibbear on 01/18/03 03:11 PM.</EM></FONT></P>
 

SplinTAH

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I originally wanted to buy a thunderbird chip, as they run at 200fsb like the Duron. However i can't find any UK shops/websites that sell them for a fair price :\ I think AMD are discontinuing them. If i do buy an XP and it doesn't work, I will probably have to upgrade my Duron from the 750 that it is up to a 1.3ghz. I really want to run an XP tho :/

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bronibbear

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An Athlon XP will probably run ok but will probably have to put up with it underclocked. An XP 2000+ runs at 1670mhz (133fsb x 12.5)on 266fsb motherboard on yours it will achieve 1250mhz (100fsb x 12.5)about the speed of a 1.3gig Thunderbird so it probably would pay you to buy one of these. A Duron 1.3gig would probably work fine but because it has a smaller L2 cache would not perform as well and still only be a Duron 1.3 if you decide to upgrade your motherboard where as the Athlon XP would become a fully fledged 2000+!
 

tombance

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You can buy an Atlon 1.33 266 from Komplett.co.uk for £40, although you would need to unlock it and then chande the mutliplier to get it upto it's full speed.

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Civilized

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This is what I was trying to tell the guy in my first post....with the higher fsb that these processors have (133mhz) your default multiplier will be much lower than of the tbirds with the 100mhz fsb....since the multipliers are locked unless you go through the process of unlocking them he would be cheating himself....besides the ECS k75SA that fully supports this processor (and supports sdram and ddr for future upgrades) is only like 50 us dollars so why not go ahead and do this?
 

tombance

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good point, he would save a lot of hassle by just buying a new board with SDRAM support or a new DDR board and RAM.

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bronibbear

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The Athlon 1.33 266FSB is unlocked! From 1.2 to 1.4 gigahertz AMD started shiping the Thunderbirds with the L1 bridges closed (266FSB not 200FSB ones) this means that the default multiplier can be changed easily either by the bios or jumper setting (depending on your motherboard) without any physical modifications to the chip!