why wont this prescott go any faster??

[Dizzzzz]

Hi guys.

Another noob here with more vague questions.

Here my current system:

prescott 3.0e 1mb cache @ 3526 (235fsb) @ 1.4357 vcore
asus p4c800 e delux @ 72.73/36.36 agp/pci
2 x 512mb OCZ PC4400 Gold Series Limited Edition EL-DDR CAS3.0 @ 2.5/4/4/8/8/16t/7.8uS @2.65v
turbo mode on, performance acceleration something or other also on
um, ati radeon 9800pro, 2 x westdigi 250mb sata drvs dvdrw/cdrw.
450w jantech ps

And I'm stuck. I've only got air cooling, in an antech p160, but at load its only running 48c, and 36/38 idle (with a few fans). but it wont go any faster, at all, either memory failures in memtest, or prime95 fails pretty quick.

One thing I noticed is the Vcore fluctuating in speedfan. when its idle, it sat at 1.4v but when its getting loaded (haha, just read this back to myself), the vcore drops. I noticed that it seemed to fail prime if the vcore went below or stayed around 1.32v, so I pumped up the vcore to 1.4375 and now it drops to 1.35v and doesnt fail prime95 anymore, or get memory failures.

so..........if fsb is related to keeping the vcore above 1.34v (um, is it?)what is the max I can keep the vcore at when its idle? my pc is on 24hrs a day. Also, I set the vcore to 1.4375v now in the bios, but mbm reads 1.44/1.46 as does speedfan, so which one is right?

I was hoping to force this thing to 250, is that unrealistic?
any other tips?

cheers guys.

EDIT: i've just read the prescott voltage thread so, 1.5v max huh? still got the bios vs speedfan question tho. and am I on the right track with the v core? I dont want to increase it unless I have to.

 

[Chocobo]

increase your vdimm. The ram you have i think takes 2.9 default volts

 

[batboy]

Yeah, try giving it a little more vdimm and maybe play around with relaxing the timings if you are getting memory errors.

Well, you got decent cooling, but still, trying to hit 250 FSB might be tough on air. The real problem is the vcore droop under load. Those Asus mobos seem to get worse and worse about it. There is a mod that can be done to help, but it requires soldering your mobo.

Also, heavy overclocking of those Prescotts require a really good power supply. Don't know much about that one you have. What are your load 12v and 3.3v rails?

 

[bchur83]

Along with what was said above, lock your AGP/PCI @ 66/33. That is most likely your problem getting any higher FSB other than your ram. Especially ATI cards don't like high AGP bus speeds.

 

[Sophisticated]

yes i noticed you AGP/PCI are pretty high.....give your mem more VDIMM as mentioned and use 3-4-4-8 timmings

 

[Dizzzzz]

thanks guys. I upped the vdimm to 2.85, the highest on this boards bios. it never really helped. I did try relaxing the timings, well the only thing I can relax anymore is the cas, and I tried that on 3.0 but no go.

why would the pci bus make any diff? every thing is prefectly stable now, and the freq is locked aint it? so inc the fsb would still leave the pci bus the same wont it? ...... it'll try it anyway tho, when I get home.

this droop mod? are talking kiddie soldering, or techy soldering? could you show me a how to?

as for the power, I guess that'll be on the power supply label? I'll check that also, but 450w not enough????

 

[Sophisticated]

if u take the PCI bus really high it can corrupt data...convinced????

 

[Dizzzzz]

thanks, but that doesnt really explain it.

my point was : I'm running at 72 now, its fine, if I inc the fsb to 100000000000000000000000000, the pci bus is still 72, so wheres the corruption? I'm going to try dropping it anyway, but I'm trying to understand this stuff, as opposed to just following instructions.

also, something I noticed last night. I set the fsb to 245 set the timings to 3/4/4/8 and my pc constantly reboots when memtest tries to load. power?

 

[bobad]

Originally posted by Dizzzzz
One thing I noticed is the Vcore fluctuating in speedfan. when its idle, it sat at 1.4v but when its getting loaded (haha, just read this back to myself), the vcore drops.

How many times do we have to tell these N00b's: This is your RAM, this is your RAM on drugs. Any questions?

Do you have another power supply you can borrow?

 

[theflyingrat]

Re: Re: why wont this prescott go any faster??

How many times do we have to tell these N00b's: This is your RAM, this is your RAM on drugs. Any questions?

Do you have another power supply you can borrow?

Right you are - unstable voltage and current, I think, are probably the most common cause of components doing funny stuff when they're under load. Poor enough voltage regulation can even cause stability problems at default speeds, when the components should be running perfectly in spec.

As for the "Really high PCI bus...." 36MHz is "really high" nowadays? Boy, you should've told me that when I was using the KT133A and i815 a few years back. I should have never gotten overclocks the way I did!

 

[kc428]

Which bios revision do you have? Make sure that you have the latest one because they had some prescott fixes in it for the p4c800s. At least I had to flash mine to make it work better.
Kevin

 

[aNTiChRisT]

If you've locked your PCI/AGP to 66/33 then its probably the ram.

Also, voltage stability is key -- if you have to up the volts to 1.5 because at 1.45 it dips below 1.4 (1.4 is needed to keep it stable) that is more potential voltage than needed.

~t0m

 

[Dizzzzz]

thanks guys.

so my ram is tripping, cos my PS is feeling lazy?

I think I'm going to get one of those TRUECONTROL 550 ps's, I dont have a more powerfull one I could borrow. at least it should keep me powered for 1 or 2 more cpu's.

I'm on bios v 1.016. v 17 is in beta at the mo.

I'm still worried about the different reading between the bios voltage and what speedfan records as the vcore. Anyone shed some light on that, who do I believe bios, or speedfan?

thanks for help guys.

 

[aNTiChRisT]

Heh, speedfan reads its measurements straight off the bios...

~t0m

 

[GST-97]

About memtest... make sure you get the newest version from www.memtest.org , not the old version.
They had rebooting problems on prescotts. new version fixes that.

PC4400 OCZ might not be so great on that board as I think 2.8V is default voltage, 2.9-3.0V would be the best to get high speeds.

Also, turn off turbo mode and any performance settings, those try to tighten ram timings which your RAM just most likely wont do.

-Chris

 

[Dizzzzz]

thanks, that was the memtest problem. I have a new version and it runs better.

I've got the vdimm at 2.85 now, the fsb is prime stable at 240 (3hours so far, and I'm bored now). The vcore is now 1.45 bios, and the mem is at 3/4/4/8

I'm still not hitting a heat problem, I think I'm going to be too scared to go any higher voltage, but it just brok 51 degrees under the prime95 run.

If I go more than a couple mhz higher on the fsb, it starts to fail prime. I dont really want to go any higher on the voltage, or am I just being a panzie? I thought I'd run out of cooling ideas before I chickened out of the vcore?

PAT wont disable, the options are auto or enabled, and in cpuz its allways enabled.

The vcore definately fluctuates between load, and idle, heres a pic is that normal? do i need more stable vcore? is that power supply gonna be worth it, and more importantly, do you think its got a good chance of straightning it up, or do you think its a motherboard thing?
or if thats normal, when, what next?

 

[batboy]

I'm glad that GST-97 provided the memtest info about needing the new version for the Prescott, that's good to know. CPU core temp of 51 is good, you could try a little more vcore, but watch out for mobo mosfets overheating. A little voltage flucuation is normal. It's when there's a wide swing or if load really pulls voltage down a lot is when you need to worry. Overclocking a Prescott requires a really good power supply. Sounds like you are finally getting your system worked out, good deal. If you visit the Asus motherboard section on the forum, there should be a sticky about modding your mobo. Might visit the volt mod section too if you get serious about trying it.