old P4 chip question

[dbarton]

I have a p4 with a 2.26 cpu. bios reports it running at 2200. 18x multiplier 133/33. no problems.

but, today I swapped in a 2.8 cpu. bios reports that running at only 1800, with a 14x multiplier. odd?

nothing I could do would get the 2.8 running anywhere near 2.8.

is this 2.8 designed for a faster system bus? It says 800 on it , and I think my mobo is 533. Is that related?

I looked in system after it booted, and it definitely report it as a p4 2.8
Is this chip bad?

 

[stevty2889]

If it's an 800mhz FSB and your motherboard only supports 533, then that is the problem. It has a 14x multiplier if it's an 800mhz FSB chip. 14*133(for 533mhz FSB) would put it around 1860mhz.

 

[Rabbits]

Yeah what stevyty said, your motherboard is messing up your clocks.

 

[dbarton]

Gotcha,
so short answer is stay with the 2.2 cos there is no solution, right?

thanks guys!

 

[myocardia]

No, the short answer would be to buy a P4 2.8B: http://www.starmicro.net/detail.aspx?ID=118 You mistakenly bought a 2.8C.

 

[dbarton]

Ah, thanks. I didn't buy this chip. Grabbed it out of a junk machine, so I'll just stick with the 2.26.
thnx

 

[Arkaign]

What mobo do you have? Do you have any control over FSB? I've seen some socket 478 mobos that were stock 100 or 133fsb (400 and 533, respectively), that would let you bump the clock up a bit. If you can change the FSB from 133 to ~166, then you will get ~2.4Ghz, and a bit of a boost compared to your current CPU (Hyperthreading should help some as well on that 2.8C).

 

[dbarton]

It's an ASUS p4t533c. When I put the 2.26 back in, I tried 140/35, but it rebooted after about 5 mins. I kept lowering it to now I'm at 136/34, so my 2.26 is at 2.31. Obviously not much difference.

The highest setting I got with that 2.8 chip was about 1900, because i think it only goes up to 150.

 

[Arkaign]

Wow, that's an old RDRAM mobo! That's probably what's tripping up your overclocking. You might need to lower the memory clocks/timing in order to achieve higher FSB, particularly if your RDRAM modules aren't very fast. It's been a while, but I remember the timing on RDRAM being a bit more complicated than DDR1 was. The chipset itself, the i850, is outstanding, but the RDRAM interface can throw some difficulties at you. It warrants some research.

 

[dbarton]

The memory is 1066, so seems like speed should be ok.

I'm not sure what's going on, but I just ordered parts for a fancy new machine so I guess I'm gonna not worry too much.
Maybe I'll get a 2.8B since it's only $45, and use as a second machine.

thanks for everyone's input!

 

[Arkaign]

Originally posted by: dbarton

The memory is 1066, so seems like speed should be ok.

I'm not sure what's going on, but I just ordered parts for a fancy new machine so I guess I'm gonna not worry too much.
Maybe I'll get a 2.8B since it's only $45, and use as a second machine.

thanks for everyone's input!

The speed, if you can control it, is crucial. When you increase FSB, you're also increasing the memory clock. RDRAM is very sensitive to increases in clock speed beyond its rated speed. So taking the RDRAM from 1066 to faster speeds is probably your wall. If there is a selection that lets you start the RDRAM at 800 mode, then increase from there, that will let you overclock much higher.

This is all hypothetical, as I have no direct experience with that particular configuration, but it warrants a few moments poking around through the bios to see what options are available for memory clock and timing. The 2.26 you might be able to get to ~2.6 or higher pretty easy

 

[dbarton]

Interesting. I'll reboot and do some poking around now..

 

[dbarton]

I just changed "rdram/fsb frequency ratio" from x4 to x3, and changed "rdram turbo mode" to disabled.
not sure exactly what the difference is, but will not boot if I leave it at 4x with the fsb upped.

CPU ID says dram is now at 450, where it was at 533 before, so not sure if I've done anything useful or not.
I set fsb to 150/38 which is the highest setting, and CPU seems to be running faster at 2.55.

fsb reported at 600 / bus speed 150.
CPU and MB temp are at 35/36..

I also upped cpu voltage from 1.5 to 1.6 - that make sense?
so CPU faster, memory slower?

seems to work.

 

[stevty2889]

Not bad. You could try for a little more. If you can get your FSB to 177, with ratio at x3, it will put your ram back around 1066(531mhz, 1062 effectively), and would put your CPU at 3ghz. 165mhz FSB would put your CPU at 2.8ghz and your memory at 495mhz(990mhz effectively).

 

[dbarton]

That sounds good, but I'm on the highest settings the bios will go to!
Have I still gained something by upping CPU, but slowing down ram?

 

[Idontcare]

Originally posted by: dbarton
Have I still gained something by upping CPU, but slowing down ram?

The answer is almost always YES with rare exception in the past 20 yrs. More cpu clocks trumps more ram clocks for just about every desktop app.

 

[myocardia]

Originally posted by: dbarton
I also upped cpu voltage from 1.5 to 1.6 - that make sense?
so CPU faster, memory slower?

seems to work.

Put your vCore back to 1.5v immediately. Ever hear of Northwood Sudden Death Syndrome? You don't add vCore to Northwoods when you overclock them. They're like Core 2 Duo's; they overclock a long way on stock vCore. Nearly all Northwood B's will do at least 3.0 Ghz on stock vCore. The difference between Northwoods and C2D's, though, is that it's very easy to kill a Northwood by raising the voltage, unlike the C2D's.

Have I still gained something by upping CPU, but slowing down ram?

Higher RAM speed will gain you about 1/1000th as much performance (1/10th of one percent, IOW) as higher CPU speed will.

 

[dbarton]

No, had never had heard of it.
I'm now back at 1.5v and still seems to work just fine.

Is there some standard test program you guys all run?
can't recall if Sandra has anything..

 

[myocardia]

I'm assuming you mean to verify that the overclock is stable? If so, read this thread for more info.

 

[dbarton]

ok, thanks.

 

[Arkaign]

I recommend checking what Bios revision you have, apparently the newer versions add support for more CPUs, and may in turn unlock the ability to go beyond 150FSB, though certainly not necessarily.

It seems your mobo has gone through quite a few Bios revisions to add/strengthen support/features over time.

 

[dbarton]

Originally posted by: Arkaign
I recommend checking what Bios revision you have,

I do appreciate that, but I'm on the very latest beta bios now.
Still, I gained a few mhz, so all is good.

 

[Arkaign]

Originally posted by: dbarton

Originally posted by: Arkaign
I recommend checking what Bios revision you have,

I do appreciate that, but I'm on the very latest beta bios now.
Still, I gained a few mhz, so all is good.

Awesome AT FTW once again

 

[PlasmaBomb]

Oldskool

dbarton - were you asking about buying rd ram over on the other subforum?

 

[dbarton]

Yes, I was asking about RDRAM for this same machine.

In the end, I was convinced a new machine would be a good idea, so now have one to build in the next few days, but this p4 will stay as a spare.