~misfit~ wrote:

I'm running a Tualatin Celeron 1.3Ghz in a Gigabyte GA-6VEM-L integrate=
d
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 s=
peed
from the CPU and it then allows you a certain overclock (in BIOS) from
there, in pre-determined steps unfortunately, I can't go one Mhz at a t=
ime.
Well, my 1.3 is running 24/7, Prime95-stable at 124Mhz FSB for 1.612Ghz=
=2E 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 t=
his
CPU has always ran a little high, 1.53 average according to MBM5, rangi=
ng
between 1.51v and 1.54v. (Strange because I had a Celly 1.4Ghz in this =
board
last week and it only ran at 1.35vcore. It ran fine though, however I d=
idn'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 motherboards=
=20
as well but it's not a problem here as I always have something else setti=
ng=20
it.

The tualatins using an open drain FET to set the Vcore identification pin=
s=20
whereas the earlier celerons used straight wire shorts to ground. And the=
=20
specs for earlier tualatins specify the motherboard pull up to be 10K, or=
=20
more, while the tualatin says 1K. I could imagine that the 10K "or more" =

pull-up on the non tualatin motherboards is not always sufficient to driv=
e=20
the pin high when it's not being pulled low by the on-board FET.

Which would be a great theory except for not explaining why yours seem to=
=20
be 'high' instead of low, as that theory would expect. Unless the on-die =

FET pull downs depend on some Vss pin that's 'unused' on earlier motherbo=
ards.

Whatever the reason, I've seen it too.


Now, 1.61Ghz is pretty damn good I figure. (Even though it's a dreaded =
Via
chipset board I get 107 marks with CPUMark99, up from 84.9 at 100Mhz FS=
B).
From what I can tell I can't monitor die-temp with this board. However
socket temp sits at around 29=B0C, case temp 19=B0C, crunching SETI ful=
l-time,
about the same as the 1.4 did using it's stock HSF. It's winter here.
=20
I'm never satisfied with an OC until I've reached the point where I get=

errors in Prime, then backed off to my last stable setting. I can't do =
that
with this set up as-is. Also the PCI bus is 41Mhz, a setting I'm not ex=
actly
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 forgiving=
card
bus-speed-wise, everything else is on-board. (I haven't tried my scanne=
r at
this speed though). The HDD is an old 8.4GB Fujitsu. The board actually=
has
three bulging capacitors, with two of them leaking a little on top. I h=
ave
replacements ordered and they should be here in a few days. I was going=
to
replace them as soon as they arrived, however, with it running this wel=
l I
might just leave them as they are until I *have* to replace them (unles=
s I'm
risking my CPU?)
=20
So, the question: Can I easilly (and non-destructively in case I need t=
o
revert back) fool my mobo into thinking it's a 133Mhz FSB CPU? It does =
run
133FSB CPUs. That way I could try for 1.73Ghz and have the PCI back in =
spec.
I realise that there isn't a very good chance of me getting it to run a=
t
that speed (especially with no vcore adjustment) but this *does* seem t=
o 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 increase, =

but who knows? It's already doing better than average to be stable at 1.6=
=20
Gig at stock Vcore.

=20
Can it be easilly done?

Unfortunately, no. The bus select pins are pulled high on the motherboard=
=20
with pull downs on the processor to select which speed it wants and to ge=
t=20
133MHz as the 'requested' FSB you need to break the pull-down on BSEL1=20
(AJ31) so that it goes high (on the VRM side). The obvious way is to brea=
k=20
the pin, but that isn't replaceable (for most mere mortals anyway). The=20
alternate is to insulate it somehow.

Vcore, btw, can be increased by jumpering processor pins to Vss. You don'=
t=20
have the choice of just any voltage because you can't make a pin go 'high=
'=20
with that method but, with a 1.5 volt default Vcore, you can get 1.55, 1.=
6=20
and 1.65. The next higher jump, by only jumpering to Vss, is to 1.9.

The really ambitious have been known to break the motherboard traces to t=
he=20
socket and wire in their own DIP switches for the VID and FSB signals to =

make both adjustable.

This is my second machine, mainly used for SETI
(BOINC actually) and a bit of 'muling' in multiplayer Diablo2 games.
=20
I have seen a web page with other people's OCs on it, some overclocking=

site. Does anyone have the URL? I'd be interested to see how far others=
have
managed to push their Tui Cellys.
=20
Also, Spajky, what speed do you have your Tui at and how many marks doe=
s it
get with CPUMark99 on a BX?
=20
Thanks in advance for the replies folks.
--
~misfit~
=20
=20