underclock a Tbird on KT133A?

fergus

Member
Dec 21, 2000
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I have a Tbird 900 and will be getting a KT133A board. Don't know yet if I will try overclocking but I want it to run at 133mhz. To do this I will have to connect the L1's to change the CPU multiplier. If I do and I run it at 6.8 x 133 to get 904, can I remain with the stock retail cpu fan and not worry about additional cooling mods? Also, might I need to change the voltage?
 

Dark4ng3l

Diamond Member
Sep 17, 2000
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you cant set the multiplier to 6.8 only 6.5 or 7 . You need to cenect the l1 bridges to change the multiplier.
 

fergus

Member
Dec 21, 2000
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Will 7 x 133 for 931 require cooling efforts beyond the stock hs/fan?
I guess I have some basic questions about overclocking. Such as regarding a CPU, will it require super cooling whether you overclock only by multiplier or only by fsb? Is it clock freq or resulting mhz that will determine the temp? For example a "retail" Tbird 900mhz with 200fsb on a KT133A with 133fsb:
9x133= 1197, the multiplier is at it's rating but result is not 900. Get hotter?
10x120=1200, it's oc'd and will require extreme cooling but is it because it's at 1200 or because we asked the clock to run at 10 instead of 9?
7x133=931, it's underclocked but the cpu freq is higher than 900. Is the retail stock cooling fine or will it require better, and if so is it because it's running at 931 or because we asked the multiplier to run at a timing other than 9?
thanks
 

Moonbender

Golden Member
Oct 19, 2000
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For cooling, it doesn't matter whether you overclock with FSB or by multiplier, the heat generated is the same. The only difference between 6*133=900 and 9*100=900 is that the bus speed between CPU and the chipset is higher, so the latter will be some percent slower.

Your stock fan will probably work fine at 931 Mhz.
 

Assimilator1

Elite Member
Nov 4, 1999
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fergus

Overclocking refers to the cpu speed & not the multiplier.
Your 900 @ 933 should be just fine with the standard hsf & cpu voltage.
 

Hanky

Senior member
Dec 29, 2000
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Now, I have one more question...

If I have an "old" T-Bird (specified for 100MHz-DDR FSB) and run it on KT133A at its specified internal frequency (with multiplier adjustments) but FSB 133DDR, could this mean any problems for the CPU or is the internal frequency all which matters for the CPU?

Thanks.
 

fergus

Member
Dec 21, 2000
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to my knowledge, the only compatibility issue between the "older" 100/200fsb Tbirds/Durons and the new 133A boards is that the cpu's clock is locked: a 900 is locked at 9, an 850 at 8.5, etc. If you unlock it and adjust the clock multiplier accordingly it will perform perfectly with the 133A at 133fsb. My 900 example, if run at 9 x 133 would be overclocked at 1197 and, if it worked, would likely require extreme cooling to keep from frying. But you can run the 900 on the 133A, not at 9x but at 7x (7x133) to reach 931. Running the cpu below it's rated clock will not hurt the cpu performance.
 

DaddyG

Banned
Mar 24, 2000
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Most of the new KT133A mobos support both multiplier and FSB overclocking. So, if you connect the L1 bridges and adjust your core voltage higher you have lots of options. With high quality RAM, Durons and TBIRDS (regular models) have been reaching 150FSB.

Solteks new KT133A mobo even has Auto Overclock in the BIOS. When used it ups the FSB to the highest possible without errors, pretty neat.