Overclocking Escapades: socket LGA1155 Intel Core i5 2400

[Tech Tweaker]

So, got this Intel Core i5 2400 (stock 3.1GHz (100MHz BCLK x31 multi) in last week and figure I may as well see if I can get some kind of an overclock with it.

So far I've got it running stable at 3.2GHz (103.2MHz x31) for an hour test on Prime95. I was using 1.27V for this, which is probably more than necessary, but I just went with the max voltage it was using under load with CPU vCore set to auto. I'll ease that voltage down later to find what the minimum for stability really is.

Now I've turned on Turbo Mode, which seems to be working great by the way! At the moment with Turbo enabled I'm at 3.5GHz no matter what I'm doing (which seems faster than 3.1GHz). Ran Prime95 for an hour with no signs of instability, still at 1.27V.

Temperatures are quite reasonable so far. Under load with Prime95 the max I've hit so far has been 52°C (50-52-52-51). I'm using a Thermalright Ultra 120 Extreme for cooling with a couple of Cooler Master SickleFlow fans on it, because the stock cooler sucks and I was hitting 60°C easily with it.

CPU: Core i5 2400
Motherboard: Asus P8Z77-V Pro
RAM: G.Skill RipjawsX F3-12800CL7D-4GBXM
GPU: EVGA GTX 260 192 Cuda Cores
HDD: Seagate 2.5" 80GB Momentus 7200.1

 

[xsuperbgx]

These locked multi CPUs are fun to try to push. What board are you using? I have been up to the 108-109 bclk range on an mvg. On the mvg there is a bclk skew setting that may help, I don't know if other boards have that setting.

 

[Tech Tweaker]

These locked multi CPUs are fun to try to push. What board are you using? I have been up to the 108-109 bclk range on an mvg. On the mvg there is a bclk skew setting that may help, I don't know if other boards have that setting.

I'm using an Asus P8Z77-V Pro.

Yeah, I forgot to list test system specs.

 

[Tech Tweaker]

Well, 3.5GHz was stable for an hour-long test on Prime95 blend.

Now I'm trying 3.6GHz, since I figured out how the raise the Turbo multiplier. I can take that all the way to 38x, though I'm not sure if it will be stable or not at 38x.

Edit: 3.6GHz was stable, completing a two hour run of Prime95 with no errors or warnings.

 

[Tech Tweaker]

And 3.7GHz was also stable.

Hitting maximum temps of 51°C-52°C-53°C-52°C under load.

Onward to 3.8GHz I suppose, as I see no signs of it stopping.

 

[wingman99]

Overclocking a locked chip intel allows 4 Bins overclock however if I recall correctly only (1) core will run 3.8 (2) cores 3.7 (3)cores 3.6 (4) cores 3.5... However I have seen in reviews that some motherboards have bypassed that and are able to run the locked CPU's with all 4 cores at 4 Bins.

 

[Tech Tweaker]

Well, that's some interesting information.

It seems I can run all four cores at 3.7GHz at full load. However, if I increase the turbo multiplier to 37x with my 103.2MHz BCLK for an effective speed of 3.8GHz it will drop back to 3.7GHz with a 36x multiplier if I utilize more than two cores at once.

Edit: enabling the 38x multiplier has the same effect, dropping back to 36x for 3.8GHz (36x105.2MHz=3788.59MHz) when all four cores are loaded. Only going back to 4GHz (38x105.2MHz=3997.6MHz) when at idle with little or nothing going on.

 

[wingman99]

That is interesting about BCLK increase with turbo you loose clock speed.

Is the main multiplier, not the turbo for all cores grayed out?

Also what is your temp? That can reduce your clock.

 

[Tech Tweaker]

That is interesting about BCLK increase with turbo you loose clock speed.

Is the main multiplier, not the turbo for all cores grayed out?

Also what is your temp? That can reduce your clock.

I couldn't even find the option for the regular multiplier in my bios actually. Whether that's because I've disabled some option that needs to be enabled, or not disabled an option that needs to be I can't say.

Hitting maximum temps of 51°C-52°C-53°C-52°C under load.

 

[Tech Tweaker]

Well, it seems I've found this CPU's maximum frequency.

Single core: 4024.96MHz (38 x 105.92MHz)
Four cores: 3813.07MHz (36 x 105.92MHz)

Any higher on the BCLK and the system won't pass POST.

Load Temps: 50°C-52°C-53°C-52°C

 

[Silver_Pharaoh]

Subbed.

I too would like to OC my i5 2300 one day using this method.

 

[Tech Tweaker]

Well, it seems bit-tech.net found the same max speed for this processor that I did. I never even found this review until after I attempted overclocking the processor. Actually, I just kind of jumped in head first without reading anything first, which might not be the best way to go about overclocking on a platform which you are unfamiliar with.

http://www.bit-tech.net/hardware/cpus/2011/01/03/intel-sandy-bridge-review/14

 

[Tech Tweaker]

Now attempting to find what the lowest stable voltage for the CPU is.

Subbed.

I too would like to OC my i5 2300 one day using this method.

Glad I could help.

 

[Silver_Pharaoh]

Now attempting to find what the lowest stable voltage for the CPU is.



Glad I could help.

No extra Vcore needed? Wow, now I REALLY want a Z77 or P97 mobo

Too bad I haven't found one where I can buy with bitcoins

 

[wingman99]

Good clock, what does it do with 4 cores if you only raise the turbo and not the BCLK.

 

[Tech Tweaker]

No extra Vcore needed? Wow, now I REALLY want a Z77 or P67 mobo

Too bad I haven't found one where I can buy with bitcoins

Not only did I not need ANY extra Vcore (which surprises me, quite frankly), I've reduced it to below my chip's VID, and it's still stable.

My VID is 1.246V (oddly it shows 1.33V when I'm under load), but I'm at 1.21V and still fully stable.

These were after a run on Prime95.

Good clock, what does it do with 4 cores if you only raise the turbo and not the BCLK.

I'll have to look into that, but I'm assuming it will still drop back to the 36x multiplier for 3.6GHz (100MHz x 36).

 

[Silver_Pharaoh]

Stock cooling too?!

 

[Tech Tweaker]

Stock cooling too?!

No, something bigger. I'm using a Thermalright Ultra 120 Extreme (TRUE).

 

[Tech Tweaker]

That is interesting about BCLK increase with turbo you loose clock speed.

Is the main multiplier, not the turbo for all cores grayed out?

Also what is your temp? That can reduce your clock.

Finally found the place to set the main multiplier for the CPU manually in my BIOS, so I manually set it to 38x. Wasn't where I was expecting it, it was in a sub-menu.

So, I'll see what that does.

Good clock, what does it do with 4 cores if you only raise the turbo and not the BCLK.

It does the same thing, drops the multiplier to 36x and runs at 3.6GHz.

 

[Tech Tweaker]

The system runs the same if I set the CPU multiplier to 38x as if I set the Turbo multiplier to 38x, it will drop the multiplier to 36x when I load up all four cores.

So, with the BCLK at the stock 100MHz it will run at 3.6GHz with all cores loaded.

Seems as if this is a built in max multiplier for if all cores are loaded, or perhaps an intentional safety feature of some kind.