Overclocking a P4 2.8E

smack

Guys,

i am trying to overclock my system.
I have a epox 4pca3+ mainboard, 2.8 prescott, and 512Mb kit DDR Gold PC4000 Dual Channel CAS 2.5 4-4-7. Zalman ACU7000, 9800pro flashed to xt, with artic cooler.
Also have bios on mainboard flashed to newest available version.

What i did was increase the FSB from 200 up to as far as 230 and thats as far as it will go, after that it wont boot. There are no settings in bios, for vcore voltage and the multiiplier cannot be changed. So the only thing i can do is raise the FSB. I have read about guys getting the FSB up 260 or so and was wondering if i am doing anything wrong.

Col_Loki

Overclocking is alot about luck you might just be slightly less lucky than others have been.

What are your temps like? Have much air flow? When did you get the chip and where (trying to see if its the new stepping)?

Its strange you dont have any options for voltage increase, thats most lightly whats stopping you from going further. Are you sure there isint an option to do it (im not well up on Epox boards, not much of a fan)?

smack

i bougth the cpu at Komplett, about 2 months ago. CPU-z reports the cpu as

family F
model 3
stepping 3
ext family/model 0
revision C0

my temps are at 38-40 running idle with my current overclock to 230FSB-3.23Ghz, 52 at full load

Cant find anything about increasing vcore voltage in the bios, i thought myself there should have been something there, cos these boards were suppose to be able to increase voltage by a little, from what reading i was doing. I have looked around and i can do a voltage mod to the board, but not too keen on it just yet (last resort).

So are you saying thats whats holding me up now is the need for a vcore voltage increase or should i be able to go higher with the FSB

Col_Loki

Looking at HardOCP's review .........

AGP voltage settings are adjustable by BIOS
CPU clock settings are adjustable by BIOS
CPU multiplier settings are adjustable by BIOS
CPU V-core settings are adjustable by BIOS

The fact that it says you have multiplier adjustment and you cant actually change it is purely down to intel having locked there chips.

It says it has V-Core adjustments, have a look at your BIOS again, set options to "user define" or simular, there has to be a way to do it......
I know on the ASUS A7N8X you have to set two settings to user define to get 1mhz increments on the FSB. Its probably badly labeled.

At the min its looking like the Vcore is the problem, temps are decent for a prescott so you have a little room (i assume thats prime95 load temp?). And Pc4000 memory means you should be fine up to 250mhz FSB memory wise .

As i have said in other threads im not well up on epox boards so sorry i cant be of more help with the voltage thing......

PS whats the memory voltage (VDIMM) at? I know the OCZ needs a good bit of juice to be stable at that speed (if i remember correctly).

[edit] I wouldnt increase the Vcore too much on the Prescott btw, just a little and see if that helps........ pretty hot chips and need alot of power from the motherboard (increasing Vcore too much ie 1.6v has a chance of damaging the board)....... but depends alot on the board, and overclock aswell.

BloodBath

Depending on temps your safe enough to 1.55 on Prescott Vcore. I'd say your BIOS is defaulting your Vdimm to 2.6. You would want to up this to 2.8 to get the RAM stable at 250mhz fsb. The Vcore will probably need to be raised as well.

Try and keep the max temp below 60c.

Providing your cooling is decent you should be able to get 3.5-3.7 out of it. I wouldn't take far cry as an accurate measure of full load. Use prime 95 and monitor the temp for about half an hour to get a good indication of real max load temps.


BloodBath

jesus_thats_gre

I am current runnig stable at 3.4 or quite easily. I also have the exact same RAM. I can't remember exactly how I have everything set up though as it has been 3 or 4 weeks since I tinkered with it last.

unkel

Here's how you can change the vcore on your board:



See right in the middle of the screen where you can add or subtract from the default

Happy O/C'ing

smack

found out why the vcore setting is not there. Epox seemed to have disabled it for some reason.

Take a look at this page

http://www.epox.com/USA/article.asp?ID=1637

don't really know what theyre talking about there. So does this mean i should go back to an older bios driver if i want to overclock more.

Col_Loki

It looks like the motherboard was having problems with the power the prescotts draw when overclocked with increased voltage.... ive heard of people having simular problems (mosfets getting very very hot etc)....... thats possibly why.

Before you think about that try either raising the Ram voltage to 2.9v or using a divider and try raising the FSB......... its just something else to not have to worry about. If the Ram is at 2.6v its quite possibly a limiting factor.

Mac daddy

I have the same Ram you should be able to pump it to 2.75 no problems-

BloodBath

DDR4000 will not reach it's full speed on 2.6v. I've tried. It's recomended to run at 2.8v at this speed. Most ddr4000 is covered to run up to 2.8-3.0v.

My mobo is annoying me atm. When I try to go past 2.8vdimm it won't boot and I have to reset the cmos or reboot 3 times holding ctl + I while an annoying BIOS beep sounds off.

It used to go up to 3v with my Northwood but it won't since I changed to Prescott. God knows why.


BloodBath

the raven

slightly off topic here, but about the Vcores and the Northwoods and the like...
i'v my 2.6 northwood at 1.65v... 243fsb...
i'm getting a bit antsy now... is that vcore a bit high??
or is it just different with the prescotts?

BloodBath

Prescotts run on lower voltage.

1.65 is fine for Northwoods but I wouldn't go any higher than that on air or even water for that matter.


BloodBath