Overclocking i7 870_Please help

[bkzed]

Hi,

I am trying to overclock my core i7 870 upto 3.8 Ghz (i want to be safe I dont want to crank up to 4 or 4.2)

these are my system specs -

Processor - Core i7 870 2.93 Ghz (OC - 3.8 Ghz, 182 * 21 with +0.208 additional volts )
Heatsink - CoolerMaster Hyper 212+
Motherboard - MSI H55M - E33
Ram - Corsair VS 1333 Mhz DDR3 4GB RAM (OC Auto with 1.65 Volts)
HDD - WD 500GB 7200RPM
PSU - CoolerMaster xtream Power 600w
GPU - Nvidia QuadroFX 3800 1GB
Windows 7 Professional 64bit

Max Temps - 70 - 72 C - full load


I can run Cinebench on 3.8Ghz but it is not stable with prime95 test, if I lower it to 3.6 Ghz the prime95 runs for an hour and then I get following BSOD's -

A clock interrupt was not received by the second processor during the allowed time.
uncorrectable hardware errror
irql_not_less_or_equal

but it is not that I get only BSOD's everytime, sometimes my display goes white or blue and power and reset button dont work i have to remove and plug the power cable in order to switch it off, this happens within 1 min if I am above 3.7 or 3.8 ghz.

I was able to overclock my another system with same PSU and Ram which is Phenom II 965BE 3.4 Ghz, I overclocked it upto 3.72 Ghz without any problem. and my temp are 65 C max with prime95 running whole night.

It is stable at 3.52 Ghz with cinebench and prime95, I hope my PSU is not weak for overclocking it up to 3.8 Ghz.

Please guide me what I am doing wrong and what i need to do to get it working also if you explain how much volt needs to be given to vCore,VTT and Dram that will be great, I sick your great help on this issue.

 

[Habeed]

What does CPU-z say your CPU voltage is during a prime95 run?

What did "auto-OC" do to your RAM speed and timings?

What is your VTT set to now?

 

[bkzed]

When set to 3.8ghz, generally it starts from 1.224 volts and goes down to 1.192 volts in full stress.

the Ram speed is beetween 1400 to 1500 in cpu-z.

vtt is above 1.225 volts

my RAM is not OC ram it is the standard one, is there any problem if it goes above 1400 mhz?

my mobo is also not with P55 chipset it is H55 is there any problem with that?

In my situation if it is not possible to OC it to 3.8ghz then please guide me the safe OC setting that I can do with my current settings.

Thanks for you help

 

[Xenofin]

You really need more voltage to your cpu @3.8GHz. At least 1.26V. And overclocking your RAM, you need to increase volts here too, as you have done. But your memory might not OC with your default latency settings, ease them a little e.g. if they have default 7-7-7-24, set them to 8-8-8-24.

I have OC'ed my i7-860 to 3.8GHZ (21x181) with Vcc=1.26875V (@load 1.275V), Vimc(=Vtt)=1.225V, Vpll=1.9V, Vddr=1.6625V. Memory is running @1810MHz, 2:10, 8-9-8-24-1T (default 1600MHz, 7-8-7-24-2T) with 4 sticks (total 8GB). That stresses memory channels more so I have increased volts over specs.

My motherboard is ASUS P7P55D Evo and I can't go over Bclk 190 because of my 4 memory sticks, system will not be stable even with lower memory speed (2:8=1456MHz). With 2 sticks I could use Bclk 195 or even higher.

Overclocking capability should be almost the same with the H55 boards although I don't have experience on those, just read some reviews.

 

[Habeed]

That's your problem : those voltages are too low. My system runs at 1.36 volts under load (I'm clocked at 4.2 ghz). 1.192 is too low, especially for a system under load. The only time my cpu has voltages that low is at idle.

 

[bkzed]

my bios dosnt allow me to directly set CPU volt.

in bios it says i can set max volt somewhere to +0.400 volts

I dont know what the default volt is, in turbo mode it flucuates. how much I need to increase to get 1.275V

also my ram is standard its DDR3 1333 GHZ @ 9-9-9-24 timings, i dont know if i need to overclock it or just leave it at its default speed and timings?

and most importantly can my PSU (see above config) support for 3.8ghz overclock?

 

[Habeed]

I use +0.225 volts for a 4.2 ghz overclock. PSU is fine. RAM can be left at stock and you can OC just fine.