"Darkfalz" said:
Is this a crap overclock for a Pentium 4 3 GHz 800 FSB?
The highest I can get the FSB to go is 240, and I have to lower the RAM
speed in this case to the 5:4 ratio.
Interestingly, I think the limiter may be my power supply, which is a good
brand 250W, because stability does not improve with voltage increase (is
this normal?) and it won't even boot if I go above 1.6 volts, leading me to
believe there's not enough juice.
But I swapped in a cheap brand 400W power supply and got the exact same
results. Perhaps it has the same output on the direct 12v line to the CPU?
I would LOVE to be able to hit 250, any ideas?
Try doing some research on abxzone.com (you can spend hours over there...).
The weak link could be the Northbridge. When you increase the Vcore
voltage for the processor, that doesn't help the Northbridge do its
job.
There are several things that could affect the Northbridge:
1) One theory (I don't have any info to confirm this), is that
the 875 and 865 Northbridges use the same silicon die. The 865
doesn't have its CSA interface pinned out, so the 865 has a
lower number of BGA balls on the bottom. Intel separates the
silicon die according to their maximum clock rate, and the cheaper
865 are the slower ones from any one batch. In other words,
for best overclocking experience, you might want to start with
a P4C800 type board with 875 chip.
2) The Northbridge needs a voltage boost to be pushed further.
I haven't read about any one attacking this issue.
3) Maybe the heatsink on the Northbridge is not making good
contact. The heatsink would feel cool, while the chip itself
could be getting hot during overclock. Check abxzone to see
whether this has helped or not. Do not proceed unless someone
has demonstrated a benefit and a methodology that doesn't
damage the bare die on the chip. (The whole idea is risky
and will void your warranty for no good reason...)
875P thermal output 12.1W (page 15)
ftp://download.intel.com/design/chipsets/designex/25252801.pdf
865PE thermal output 10.2W when using 2 DIMMS (page 14)
ftp://download.intel.com/design/chipsets/designex/25251902.pdf
A good overclock is one you can do without hacking up the board.
If you are one of those rich guys who can afford another board,
then go right ahead
Is your ram premium branded ram or some generic stuff ? It could
be the culprit too.
On this site, there are 16 entries for people overclocking the
3.0C processor. You are doing well for an air cooled system.
The highest overclocks are with people using Prometeia fridge
systems. Hmm... So maybe the processor itself is thermally
limited. Also note which is the predominant Northbridge in
the listed systems.
http://www.cpudatabase.com/CPUdb
HTH,
Paul
