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Author Topic: looking for input, swap A series to B series 7455 on single/dual daughter baords  (Read 1053 times)

Ncc74656

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im considering buying some of these: https://www.ebay.com/itm/392418667981?

its my understanding hat the B series can OC much better than teh A that came in most of our systems. IF this is the case, settings clocks on this 1.25 for 1.42 on our dual cpu cards should be easy? id expect them to work just as well as a sonet no?

on the single cards... i have found info on our systems up to 1.06ghz with the resistor settings. but there are 4 resistors and WAY more possiblities of combinations. does anyone know how high a single board multiplier can go?   doing some back of the napkin math it looks like 67mhz is what each step is up to 1ghz and past 1 it goes by .06 so, would this maybe indicate that if the resistors being on from bottom to top were to continue the pattern listed -

If switches 2, 3, and 4 are on 1.36

If only switch 1 is on, 1.42

If switches 1 and 3 are on,1.48

If switches 1, 2, and 3 are on 1.54

with a FSB overclock that could possibly reach 1.7ghz for $12.00 and some time.

anyone played with this before?
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DieHard

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That is a mind-blower that the guy had 80+, brand new 20 year old CPU chips, looks like 2 left.  And they look pre "balled",  All these years I never did it, but is that a simple "heat gun drop in ?
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Ncc74656

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well you never trust someone elses balls but in a word - kind of.

boards need to be pre-heated, hot air to seat/flux.  cache swaps are hte same but firmware is required with that.   you can use a jig but on these bigger chips - you can lay the balls by hand as well.

wow, there were 12 available yesterday!   i wanted to order 5 or so...

my thougth is this: if i can get some of these CPU's and they work well, then its a 15.00 thing to go from a 733 to 1.2Ghz G4 or maybe even more...  i have seen benchmarks on giga's site and others - for cards that "new" were 500/600$$ and now can be found for well over 1300.00 with out trying very hard.    I have taken my G4 with in a hairs breath of those benchmark scores (more than others) for about 70.00 and some time.   if i can find a simple way to mod pre-existing G4 daughter cards...  a 3mb cache chip is all of 7.00, these CPUs at 1.25 being 15.00 shipped...   resistors are pennies, rom chips are a dollar each and lets be honest; soldering/flashing one of these is all of half an hour...

im going to start by trying to take my dual 1.2Ghz G4 right now and get it up to 1.9Ghz with a 3mb cache mod. i also have a single 800 with no cache so im going to add a 2mb cache chip, use factory rom, and try putting a single 1.25 onto it.

edit: i just realized those are 7445 and not 7455B like i was lookig for....  the search continues.
« Last Edit: January 09, 2024, 04:28:59 PM by Ncc74656 »
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