P2B wrote:

=20
=20
David Maynard wrote:
=20
~misfit~ wrote:

I'm running a Tualatin Celeron 1.3Ghz in a Gigabyte GA-6VEM-L integra=
ted
mobo. It doesn't have BOIS setting to change between 66/100/133, or
switches/jumpers from what I can see. It seems to get the default FSB=
=20
speed
from the CPU and it then allows you a certain overclock (in BIOS) fro=
m
there, in pre-determined steps unfortunately, I can't go one Mhz at a=
=20
time.
Well, my 1.3 is running 24/7, Prime95-stable at 124Mhz FSB for=20
1.612Ghz. I'm
pleased with that, it has a copper-bottomed HSF on it that came with =
a
Barton and stays cool, Also I removed the IHS so the die is in direct=

contact with the HS. There is no way in BIOS to adjust vcore, however=
=20
this
CPU has always ran a little high, 1.53 average according to MBM5,=20
ranging
between 1.51v and 1.54v. (Strange because I had a Celly 1.4Ghz in=20
this board
last week and it only ran at 1.35vcore. It ran fine though, however I=
=20
didn't
try to OC it at that low a vcore. Both have 1.5v written on them)



I've noticed odd Vcore values with tualatins on non-tualatin=20
motherboards as well but it's not a problem here as I always have=20
something else setting it.
=20
=20
IME Tualatins don't respond to Vcore increases anyway - at least not on=
=20
BX boards. Every Tually I've tested tops out at around 1650Mhz, and=20
won't go any further even if you increase Vcore to dangerous levels.=20
OTOH, most of my Tuallies will do over 1600 at 1.35v, and would probabl=
y=20
go even lower except Vcore tends to exhibit increasing ripple below 1.4=
v=20
on BX boards.
=20
The tualatins using an open drain FET to set the Vcore identification =

pins whereas the earlier celerons used straight wire shorts to ground.=
=20
And the specs for earlier tualatins specify the motherboard pull up to=
=20
be 10K, or more, while the tualatin says 1K. I could imagine that the =

10K "or more" pull-up on the non tualatin motherboards is not always=20
sufficient to drive the pin high when it's not being pulled low by the=
=20
on-board FET.

Which would be a great theory except for not explaining why yours seem=
=20
to be 'high' instead of low, as that theory would expect. Unless the=20
on-die FET pull downs depend on some Vss pin that's 'unused' on=20
earlier motherboards.

Whatever the reason, I've seen it too.


Now, 1.61Ghz is pretty damn good I figure. (Even though it's a=20
dreaded Via
chipset board I get 107 marks with CPUMark99, up from 84.9 at 100Mhz =

FSB).
From what I can tell I can't monitor die-temp with this board. Howeve=
r
socket temp sits at around 29=B0C, case temp 19=B0C, crunching SETI=20
full-time,
about the same as the 1.4 did using it's stock HSF. It's winter here.=


I'm never satisfied with an OC until I've reached the point where I g=
et
errors in Prime, then backed off to my last stable setting. I can't=20
do that
with this set up as-is. Also the PCI bus is 41Mhz, a setting I'm not =

exactly
comfortable with although all seems fine. The only card I have in it =

is an
Adaptec AHA-2940-AU for my old scanner and it's always been a=20
forgiving card
bus-speed-wise, everything else is on-board. (I haven't tried my=20
scanner at
this speed though). The HDD is an old 8.4GB Fujitsu. The board=20
actually has
three bulging capacitors, with two of them leaking a little on top. I=
=20
have
replacements ordered and they should be here in a few days. I was=20
going to
replace them as soon as they arrived, however, with it running this=20
well I
might just leave them as they are until I *have* to replace them=20
(unless I'm
risking my CPU?)

So, the question: Can I easilly (and non-destructively in case I need=
to
revert back) fool my mobo into thinking it's a 133Mhz FSB CPU? It=20
does run
133FSB CPUs. That way I could try for 1.73Ghz and have the PCI back=20
in spec.
I realise that there isn't a very good chance of me getting it to run=
at
that speed (especially with no vcore adjustment) but this *does* seem=
=20
to be
a good bit of silicon, I'd hate to not try it. I'm sure most of you
understand.



Unlikely you're going to get there, especially without a Vcore=20
increase, but who knows? It's already doing better than average to be =

stable at 1.6 Gig at stock Vcore.


Can it be easilly done?



Unfortunately, no. The bus select pins are pulled high on the=20
motherboard with pull downs on the processor to select which speed it =

wants and to get 133MHz as the 'requested' FSB you need to break the=20
pull-down on BSEL1 (AJ31) so that it goes high (on the VRM side). The =

obvious way is to break the pin, but that isn't replaceable (for most =

mere mortals anyway). The alternate is to insulate it somehow.

Vcore, btw, can be increased by jumpering processor pins to Vss. You=20
don't have the choice of just any voltage because you can't make a pin=
=20
go 'high' with that method but, with a 1.5 volt default Vcore, you can=
=20
get 1.55, 1.6 and 1.65. The next higher jump, by only jumpering to=20
Vss, is to 1.9.

The really ambitious have been known to break the motherboard traces=20
to the socket and wire in their own DIP switches for the VID and FSB=20
signals to make both adjustable.
=20
=20
That's why I prefer Slot-1 BX boards for Tualatins - the adapter gives =

you adjustable VID and FSB without resorting to 'ambitious' modificatio=
ns.

Yeah, unless you're using the 'super slocket III" (modified, of course).

Besides, I thought you pined for the 'old fashion' days of tape and solde=
r