Internal Clock Speed Modifications and Bios

by **ekoing** » Thu May 22, 2003 6:02 pm

Hello,

I am new on this site and I have seen very interesting topics on Bios modifications. Does anyone know if it is possible to set some multipliers to some number greater than “6x” on a motherboard of M5xx (PCChips) type ? Is it possible to modify BF0 or BF1 jumper settings in bios ?

It is because I would like to know if I could eventually try a K6-2-533AFX (2.2V) or a K6-2-550AGR (2.3V) and set it at 8x66Mhz on my M537 whose CPU Clock cannot be set to more than 66Mhz. Thus I would need to have somewhere a “8x” multiplier !

Bye, X.

by **ajzchips** » Thu May 22, 2003 8:26 pm

Useless. The CPU has to support multipliers >6x and this isn't the case.

by **KachiWachi** » Fri May 23, 2003 3:05 pm

AJZ has it right...best you can do is 66x6 for 400MHz, unless you want to over-clock the bus and step up to 75MHz (if that is supported)...then you can get 450MHz.

K6-2/+ 450 ACZ will draw less power from the regulators though, and you will need a patched BIOS to support it...

I always wondered though why you can't get a modern clock chip, make a daughterboard for it, up the CPU clock to 100MHz, and make a synchronous bus clock @66MHz...

by **ekoing** » Fri May 23, 2003 5:03 pm

Thanks ajz and KachiWachi,

And, I guess, the most powerfull cpus socket7 compatible are the K6-2 and K6-III series ? Can you confirm ? :roll:

Bye, X.

by **KachiWachi** » Fri May 23, 2003 6:19 pm

Yup...

You can a BRAND NEW K6-2/+ 450 ACZ at TigerDirect for $35 US.

by **Denniss** » Fri May 23, 2003 11:48 pm

Do you really have the M537 or the M537DMA33 ?
I don't think the M537 Voltage Regulator is capable of feeding a 400MHz CPU and supporting 2.5V or even 2.2V VCore for it

by **ekoing** » Mon May 26, 2003 7:51 pm

You're wright, Deniss.

My M537 (V3.1) cannot be set with voltages under 2.5V theoretically.
I have good help on another (unofficial pcchips) forum to manage a hardware modif to support lower voltages.
From now on, I wonder if I will use this solution or a powerleap. I may use this solution if I can use 100Mhz FSB (due to this adapter), and thus a faster Cpu.

Thank you for the Address KachiWachi.
Bye, X.

by **ekoing** » Thu Jun 05, 2003 7:51 pm

Hi, here I am back with ...
another set of questions !!!

I read the topic "Bios Disassembly" in the "In-depth High-tech BIOS section" where Jan speaks about the following numbers

"
80 ;66MHz or higher
70 ;60MHz
60 ;55MHz or lower

Note: Most newer Award BIOSes use also these FSB byte values:
B0 ;90MHz or higher
A0 ;83MHz
90 ;75MHz
"

I wonder if a bios where "B0", "A0" and "90" are set and if one's put something like

F4 EF 80 (;500MHz )

in the fsb table of the bios, how will it be interpreted by the bios ?

I know. I may bother you with this problem since ajz answered clearly to the problem, by writing :

"Useless. The CPU has to support multipliers >6x and this isn't the case."

But I would like to have a "more in depth comprehension" of the way a cpu interprets
the FSB table in the bios flash on a motherboard that has multiplier and FSB jumper
settings.
1) Do jumper settings force the cpu to read only one line of the fsb table in bios ?
2) Has someone ever tried something like the 3 bytes "F4 EF 80" on a motherboard
without jumper settings and with a newer bios ? It would be only to test if there is a possibility the cpu is recognized, so not very interesting for a motherboard that does support fsb greater than 66Mhz.
3) Is there "not secret" docummentation concerning the relations between cpu jumper settings, and bios fsb tables ?
Finally the less hazardous question :
3) How secret are the settings of the multiplier limits related to a cpu ? Does anybody know if the multipliers are "hardly" defined in a the cpu ?

I have sent an email to Amd and they didn't answer no to my question concerning multipliers greater than 6. They didn't clearly answered to me, just responding that "Amd" does only supports a set of motherboard, or something like this. Just wonder why ? No interest on it ?
some secrets to keep.

Bye, and thank you to your helpfull site.
X.[/b]

by **Rainbow** » Thu Jun 05, 2003 8:42 pm

Jumpers are set through signals configured by jumpers (or in BIOS on some boards). It depends on the CPU, how these signals are interpreted. If the CPU was made with max. 6x multiplier, it does not know anything higher and you can't do anything with that.