i5 750 OCed to 4GHz Questions

[ockarpf]

So I overclocked my i5 750 to 4ghz

Here are the specs:
i5 750 Lynnfield
Asus P7P55D
8GB G Skillz 1600

I was running fine @ 3.3Ghz when I raised my BCLK Frequency to 160.

I just installed a H100i CPU Cooler and wanted to go for 4Ghz.

I have been reading a lot of guides so please don't give me links to them.

Here is my question. I have been having issues with stability, i have been playing around in the bios and monitoring different things.

Here is where I am at now according to Cpu-z
Cpu Volts: 1.392
QPI Link is 3.2Ghz.
Bus Speed is 200Mhz x 20 Multipliers
Core Speed: 4Ghz

I have been using Intel Burn Test to check for stability well at least start there until i do Prime95

What I have noticed is that when I had Load Line Calibration Disabled at first and when I had my Cpu Volts set to 1.3825 in the Bios I noticed that on Cpu-z They would range from 1.22 -1.36 I believe this was causing the stress test to fail and sometimes my computer would shut down.

It took me a while to figure out what was causing it because I was changing the QPI Link Speed in the bios as well. So I thought that might be a factor of my instability as well but I am not sure.

I think I am stable now but my questions are the following.

1) I have read about different things about either having LLC Enabled or Disabled (i think in my case i have to have it enabled)?

2) The QPI link same thing where I am not sure to just the Auto, Lower Value (i think its 6.4ghz in the bios) or the higher value (7.2ghz in the bios). I am currently on the lower value setting which is 6.4ghz in the bios which shows up as 3.2 Ghz on Cpu-z I guess u divide that value by 2?

So if you guys could help me out with this I would greatly appreciate it.

Thanks.

 

[Vectronic]

You shouldn't have to have it enabled or disabled unless your BIOS doesn't allow for certain things, like only uses Fixed voltage, or only uses Offset voltage.

A higher level, or greater percentage of LLC will help prevent that voltage wavering, but will usually use more voltage than is necessary. +/- of 0.008 is normal for lower-end motherboards, raising the voltage or LLC might help you get a more consistent voltage, but it will likely still waver one multiple of 0.008 and another, just maybe not 3 of them.

Typically, Fixed voltage you use LLC full/max/100% (some boards just do it regardless of whether you set it to that or not)... Offset voltage you use LLC (but don't have to).

With SpeedStep/Turbo your voltages will always vary, even for Fixed voltage (again, excluding really high-end boards).

Regarding QPI, I got no advice, no experience with it.

 

[ockarpf]

What now im more confused..... What percentage of LLC are you talking about. The only options in the bios are Auto, Enabled to Disable. I didn't know you could adjust the Percentage of LLC

The CPU Voltage Mode I can choose Auto, Manual or OffSet.

Its currently in Manual mode with a Fixed Voltage of 1.3825 since that is what every overclocking thread recommends.

SpeedStep/Turbo is irrelevant right now as no guide says to have those on when over clocking past 3.5ghz

 

[Kenmitch]

I used to have a 750 at one time. I think I had to play with more than vcore to get 4GHz stable. Not sure if I still have any data floating around on my hdd or online. I use offset vcore, turbo, etc....I`ll look tonight and see if anything of use to you is lingering around and post back.

 

[Vectronic]

if you don't have LLC options (usually in 5 or 10 "levels", or in percentages 10%, or 20% steps.) then I would assume it's either 0% (disabled) or 100% (enabled)... shouldn't really matter which one you choose as long as you are in safe voltage/temperature limits.

Disabled will allow for vDroop, meaning the voltage will dip down, or even stay below what it was set to in the BIOS when it's under load. Can cause instability, and you might need more voltage.

Enabled will try to compensate and match the voltage set in the BIOS. Generally easier to get stable.

SpeedStep/Turbo is fine to use, if you can... it will save temps, power, fan noise, but you might not reach the maximum overclock your CPU can reach. If you get 4.0GHz stable and you like that speed, enable SpeedStep/Turbo, see if it's still stable, or you can get it stable with minimal voltage.

 

[ehume]

From what I remember, 20x200 is a bad number. For some reason people had trouble with it.

My second i7 860 (early 2010) ran 4004MHz at 22x182 with a Vcore of 1.31250v, with HT on and LLC enabled. IIRC the 750's could go with less Voltage because there is no HT. But I'm also remembering the temps were about 10c less, so required Vcore might have been the same.

With the 860 I was also able to run 21x191=2011MHz using the same Vcore. My i7 875K, OTOH, needs a Vcore of 1.326v to hit 4GHz. But on neither chip did I need to fiddle with other Voltages. They never seemed to make much difference. YMMV.

 

[BTRY B 529th FA BN]

If it's just a gaming machine and gaming machine only take little notice to those testers, your games will bring out any instabilities without the waste of time/money/electricity.. if I stability test at all it's usually memory test with Memtest HCI.. i can't remember the last time I used P95 or LinX for more than 5 minutes

 

[RaistlinZ]

That voltage seems awfully high for 4Ghz. My 930 does 4.0Ghz at 1.300v with HT on. I use 19.0 x 211.

How fast is your memory running? I also remember hearing bad things about 20x200 way back when.

 

[ockarpf]

Well im at 1.38 Volts and so far been stable did about 4 hours of gaming and no issues. My ram is this

http://www.newegg.com/Product/Produc...82E16820231428

And its at running at full speed with 1.5v set in the Bios.

I would feel more comfortable with using Stepspeed because that way its not running at 4ghz 24/7 it would only run that when needed (mostly when I game). But wouldn't the constant change of voltage be bad?

Btw the i5 750 max volts is 1.4 so I am below that so shouldn't i be safe?

 

[Blastman]

A fair number of 1156 motherboards have trouble making to 200 BCLK or over. In his techreport review of 4 H55 motherboards only one of them managed to get over 200 BCLK …

TR …

Let's start with the EVO, which was easily the best overclocker of the bunch. The board cruised all the way up to a 210MHz base clock

The H55M-USB3 was just as easy to overclock as the EVO, but it didn't reach quite as high a base clock speed. The Gigabyte board topped out at 190MHz, where it was stable with stock voltages. I did manage to get the board into Windows with a 200MHz base clock speed, but not without a considerable amount of video corruption and graphics driver crashing under load.

With the DH55TC's overclocking options so limited, we were left to fiddle with the base clock and quite literally nothing else. The board made it up to a 160MHz

The Zotac board's CPU multiplier controls didn't work for us, but we still managed to get the base clock up to 180MHz,

So, I would reduce the BCLK and bump up the multipier (if possible). You may be running near the BCLK limit of what your motherboard will tolerate.

 

[ockarpf]

Well Number one I don't have any of those Boards. I have the Asus P7P55D and every guide I read with my board and processor was able to make it to 200mhz Block with some tweaking.

I also can't go past 20x Multiplier since my Processor has it locked.

Right now I have been running 12hours Stable on my PC with my current settings.

Temps don't go past 36c either under minimal load and while gaming I am always under 50.

Also note in my Bios I have my Cpu Volts set to 1.3875 But it is running at 1.3920 I believe this is the LLC Enabled doing it keeping it stable.

I know if I lower the Volts to the next step smaller it will not be stable.

 

[Blastman]

Well Number one I don't have any of those Boards. I have the Asus P7P55D and every guide I read with my board and processor was able to make it to 200mhz Block with some tweaking.

I see that, but overclocking success will vary even among the same motherboards and CPU's. So even though others have stable overclocks with that CPU/MB setup at some level, YMMV. But that said, it seems you shouldn't have much problem getting to 4.0Ghz with some tweaking on that ASUS.

Apparently, if you overclock with the CPU ratio setting on auto, it will go to 21x. See … legionhardware where they did this with the same P7P55D MB as yours -- running 4.2Ghz with a BCLK of 200. So, I'm thinking you should be able to get a 21x multiplier even when overclocking, allowing you to reduce your BCLK and still hit 4.0Ghz. It's something to try anyway, if it works, and see whether the 200 BCLK is causing the instability.

This guy suggests that you will need to up the QPI voltage if you expect to run 200 BCLK …

anandtech…

Yep, QPI/VTT voltage is the key to everything. Keep the RAM multi set to the lowest # and the CPU multi to the lowest # and find the max Bclk first. Keep all voltages set to stock except for QPI/VTT which I would START at 1.20 (because you're definitely gonna need more than 1.15v stock anyway if you expect to reach 200 Bclk). Your first POST should be at 9x multi x 150 Bclk using 1.20 QPI/VTT. Go up in 10 Bclk increments till you fail Linpack 20 pass test. Raise QPI/VTT by 0.02v and try again. Rinse, repeat.

 

[ockarpf]

My Multiplier is set to Auto on the i5 750 the max is 20x. it only does 21x If you have Turbo Mode enabled but everyone recommends to leave that setting off so I will never see 21x.

I guess i could go into the bios and change it to 21 manually but not sure what will have if I try that.

Do you have the link that that whole guide u were referring to?

 

[coffeejunkee]

You should do this in two steps. First lower the cpu multiplier to its minimum and set bclk to 200. Increase the qpi voltage (i think it's called imc voltage on Asus boards) to somewhere around 1.3V. Test for stability with Linx 20 runs all memory (will take a while with slow cpu speed). If unstable, up the qpi voltage, if stable, decrease it. Once you know the required qpi voltage for bclk 200 you can put cpu multiplier at 20. Run stresstest again but this time change vcore only.

You'll need llc enabled for such high vcore. Yes, it's not optimal but it's also not that bad. Use lowest qpi link speed. 20x200 works fine, urban myth imo. It's very likely you'll have to disable c-states as well (will increase idle power, sorry no free lunch). With c-states disabled you can also use x21 multi without turbo boost in full action. But 200x20 is still better for nice 1600MHz ram.

 

[amenx]

My last CPU, 760 @ 4.2 (200x21). Main reason I chose it over the 750 was the extra multi. 1hr Prime stable. Only BCLK and voltage adjusted, everything else on auto, on gigabyte P55-usb3 board.

 

[vladicaris]

much better overclock than my amd .Do you use expensive cooler ?

 

[biostud]

I've never been able to get mine stable at more than 3.8. Not all chips will reach 4.0.

 

[Jstn7477]

My i7-870 on an EVGA P55 FTW is set at 170x22 @ 1.35v. I tried lowering the multi and raising the BCLK but the system would always flake out so I just left it at 3.74GHz and called it a day. Don't remember what straps I used or whether I had vdroop control enabled, but I think it is enabled and my RAM is at 1700MHz if I recall.

 

[ockarpf]

You should do this in two steps. First lower the cpu multiplier to its minimum and set bclk to 200. Increase the qpi voltage (i think it's called imc voltage on Asus boards) to somewhere around 1.3V. Test for stability with Linx 20 runs all memory (will take a while with slow cpu speed). If unstable, up the qpi voltage, if stable, decrease it. Once you know the required qpi voltage for bclk 200 you can put cpu multiplier at 20. Run stresstest again but this time change vcore only.

You'll need llc enabled for such high vcore. Yes, it's not optimal but it's also not that bad. Use lowest qpi link speed. 20x200 works fine, urban myth imo. It's very likely you'll have to disable c-states as well (will increase idle power, sorry no free lunch). With c-states disabled you can also use x21 multi without turbo boost in full action. But 200x20 is still better for nice 1600MHz ram.

Ok great thanks, I did some more reading and I am doing this method now. I was able to Achieve 200 Bclk with only 1.20v with my qpi/imc Voltage. My memory is set now at the proper timings, 1600mhz with my 8x multiplier, volts i left at auto. bios is showing 1.65, my ram says 1.5 but I don't think that will hurt anything.

As of right now I am slowly stress testing and Increasing my Multipliers one at a time (Im at 16 now with only 1.2v Vcore) so far so good. My goal will be to get 20x Multipliers, i will see how many Vcore volts will be required to get there. :awe:

 

[ockarpf]

oh another question I would like to add, when they mean that the computer is unstable I am assuming they mean that if either one of two things happen

1) Your Computer justs shuts down and reboots by itself
2) Intel Burn Says "Your Cpu is unstable"

Correct me if I am wrong.

 

[birthdaymonkey]

I have the same motherboard, memory, and CPU in my secondary rig.

It's been rock solid stable at 20x200 for almost two years now.

Voltage mode: Manual, 1.375v
IMC voltage: 1.3
LLC: Enabled

Everything else left alone as far as I can recall. Speedstep and C-States are on, so the clock throttles down, but it keeps the voltage steady.

 

[ockarpf]

Oh Ok yea I was going to ask if you had that speedstep on or off, Once i get my correct Vcore down, I am still debating weather or not I am going to keep it off or on.

My IMC Voltage is only at 1.2 as I did not need to increase any further for my system to be stable. when I was maxing out my BLCK at 20 with 9x Multipliers

I am currently at 18x Multipliers at 1.225vcore. we will see if that passes and get closer to my 20x Mark!

 

[ockarpf]

wow what a jump in volts from 3.6ghz - 3.8ghz
I went with a low 1.225vcore for the 3.6ghz to now a 1.30Vcore with the 3.8ghz to even get slightly stable where the computer wouldnt just restart on me durning the Intel Burn Test. I am doing 3 Passes with Intel Burn Test on Maximum.

 

[ockarpf]

So I think I am stable on my 20x 200 Blck @ 4Ghz!
Vcore bumped up to 1.375 (Cpu-z Reads 1.376)
My IMC is 1.2V
Ram is Fine with Auto Volts 1.65 and I configured the timing 9-9-9-24 - 2T
I have LLC on Auto
C State Disabled

I justed Passed Intel Burn Test with 10 passes on Maximum.

Temps don't go past 65c

 

[birthdaymonkey]

So I think I am stable on my 20x 200 Blck @ 4Ghz!
Vcore bumped up to 1.375 (Cpu-z Reads 1.376)
My IMC is 1.2V
Ram is Fine with Auto Volts 1.65 and I configured the timing 9-9-9-24 - 2T
I have LLC on Auto
C State Disabled

I justed Passed Intel Burn Test with 10 passes on Maximum.

Temps don't go past 65c

Congrats. Sounds like you're good to go.