BCLK strap overclocking on old Intel Xeons (help please)

[neurotix]

Hi guys,

 

I have a Rampage IV Formula for benching Sandy Bridge-E and Ivy Bridge-E processors for HWBOT.

 

I was wondering on any advice for voltages or settings to help overclock some ratio locked Xeons I'm getting, the 2690v2 and 2697v2.

 

Just need general info, I will be trying the 125MHz strap first and need to know what voltages I might need to adjust such as:

 

CPU PLL

CPU VTT

CPU VTT 2

VCCSA

VCORE

 

To inform you guys on what I am working with, the 2690v2 is 10 core at 3.0GHz stock and the 2697v2 is 12 core at 2.7GHz stock.

 

Thanks in advance.

[Mr. Fox]

I've never done much BCLK overclocking with locked or unlocked CPUs. The lack of a discrete CPU BCLK generator to allow asynchronous tuning can cause a lot of instability when changing the bus speed of everything rather than the CPU only. The voltage needs of the CPU might not be much different than pure clock ratio overclocking. Years ago, when laptops still mattered to me, I played around a bit with it on my Intel Extreme mobile CPUs and never found anything beyond about 101.00 to 102.00 to be stable. Running games and playing YouTube videos always ended in a BSOD or hard freezes with loud electronic buzzing noises regardless of the voltage applied. Because they were unlocked CPUs there was never much more than modest curiosity in playing with the BCLK. Elevating the core multiplier was easy enough. With a locked CPU multiplier it would have become more of an area of focus out of necessity.

 

I do always bump it about 0.050 MHz so that the clocks I set are always equal or greater than the multiplier. If I set 6.00GHz I want to see 6.00GHz. I do not want to see something like 5.95GHz instead. I also disable Spread Spectrum to help with that.

 

 

Edited March 4 by Mr. Fox

[neurotix]

  On 04/03/2025 at 13:01, Mr. Fox said:

I've never done much BCLK overclocking with locked or unlocked CPUs. The lack of a discrete CPU BCLK generator to allow asynchronous tuning can cause a lot of instability when changing the bus speed of everything rather than the CPU only. The voltage needs of the CPU might not be much different than pure clock ratio overclocking. Years ago, when laptops still mattered to me, I played around a bit with it on my Intel Extreme mobile CPUs and never found anything beyond about 101.00 to 102.00 to be stable. Running games and playing YouTube videos always ended in a BSOD or hard freezes with loud electronic buzzing noises regardless of the voltage applied. Because they were unlocked CPUs there was never much more than modest curiosity in playing with the BCLK. Elevating the core multiplier was easy enough. With a locked CPU multiplier it would have become more of an area of focus out of necessity.

 

I do always bump it about 0.050 MHz so that the clocks I set are always equal or greater than the multiplier. If I set 6.00GHz I want to see 6.00GHz. I do not want to see something like 5.95GHz instead. I also disable Spread Spectrum to help with that.

 

 

Expand  

Thanks for the advice, but I am not talking about overclocking using regular BCLK, I am talking about overclocking locked CPUs using BCLK straps. There's a few to choose from but the only viable ones are 125 strap and 167 strap (heard its more or less impossible to use 167).

 

BCLK straps ONLY affect your CPU and RAM, not the PCI-E bus or DMI. It's kind of like ECLK asynchronous for Zen 4/5.

 

The problem is, I have a known good 3970x that does 4900MHz that I tested a 125 strap with. RAM is DDR3, G.skill Sniper 1866. So I tried BCLK strap of 125 on it and changed the memory down to something close to 1866, but it failed to POST.

 

To make it perfectly clear, the E5-2697v2 I am getting has a locked ratio of 27. So normally it'd be 100x27 for 2.7GHz. With BCLK strap, it would be 27x125..3375MHz. Without affecting the Northbridge, PCI, DMI, SATA etc

 

Just need advice as other than direct BCLK overclocking (that will never do 125), this seems like the best way to OC these locked Xeons I'm getting.

 

Thanks for anything.

Edited March 4 by neurotix

[Mr. Fox]

  On 04/03/2025 at 20:31, neurotix said:

Thanks for the advice, but I am not talking about overclocking using regular BCLK, I am talking about overclocking locked CPUs using BCLK straps. There's a few to choose from but the only viable ones are 125 strap and 167 strap (heard its more or less impossible to use 167).

 

BCLK straps ONLY affect your CPU and RAM, not the PCI-E bus or DMI. It's kind of like ECLK asynchronous for Zen 4/5.

 

The problem is, I have a known good 3970x that does 4900MHz that I tested a 125 strap with. RAM is DDR3, G.skill Sniper 1866. So I tried BCLK strap of 125 on it and changed the memory down to something close to 1866, but it failed to POST.

 

To make it perfectly clear, the E5-2697v2 I am getting has a locked ratio of 27. So normally it'd be 100x27 for 2.7GHz. With BCLK strap, it would be 27x125..3375MHz. Without affecting the Northbridge, PCI, DMI, SATA etc

 

Just need advice as other than direct BCLK overclocking (that will never do 125), this seems like the best way to OC these locked Xeons I'm getting.

 

Thanks for anything.

Expand  

Sorry, I didn't understand what you were looking for, and equally sorry I've got nothing useful that I can share with you. Hopefully someone else can provide some useful advice.

[Kaz]

I was hoping you'd get better advice than what I can offer...  Most of the non-server CPUs were 'safe' to run at a vcore up to 1.3.  I haven't looked into what servers used.  I would think it's a higher number, but possibly not.  I'd take a look at the HwInfo that the cpu pulls at stock and use that to see if it's pulling more.  My 4790K was overclocked to 4.7 Ghz with the  vcore running somewhere around 1.28.  It ran that way for 5 years and then became unstable and I had to remove the overclock.  It's still a good computer, but on very rare occasions it does throw a blue screen.  When I was using it as a daily driver it would happen once every month or two.

 

I guess what I'm saying is, safe is a relative term.  CPU's that might last 12 years could drop off at 5-7 years even though the voltage is below the stock settings.  Other guys on the forums were saying they would run theirs up to 1.35 or so, which was apparently required to break the 4.7 ghz barrier for the 4790k.

 

My i7 930 was also safe to run up to 1.3.  I sold it off about a year after overclocking which was very late in it's life cycle.  That computer is still in use, not overclocked.  It's been over 16 years, but it's prone to hard freezing.

 

It's still recommended to downclock ram speed to 1333 while figuring out the CPU overclock.  Once the CPU runs the way you want it to, then it's time to see if the ram functions or if additional timing changes need to be made. 

[Kaz]

Yikes, I did some digging on the vcore settings and it looks like a stock 2690 V2 is running a 1.092 V

[neurotix]

Not all that concerned about voltages because it is heat that fries chips, not volts. I have a really good cooler for my test bench, an EK Nucleus 360mm AIO competitive with custom water. Benching on this platform, the 3970x and 4930k warmed it up a lot and I was using 1.465v to get them both doing 4.9GHz.

 

Regarding BCLK strap, I have set it to 125 and down clocked the memory since you have to, and never once have I got a system to post using it.

 

Regarding the locked Xeons, like the 2697v2 stuck at a 27 ratio, I was able to use 113.5 BCLK + the program "ThrottleStop" to get it's turbo to actually work, I was seeing speeds of up to 3.9GHz in my benchmark suite, and got a few gold cups. So I found a workaround anyway.

 

Also these chips are not for long term use, Kaz. They get benched once then sold. I doubt I'm doing any real long term damage to them.

 

Thanks guys. Consider this thread answered.

 

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neurotix`s 34749 points score: Geekbench3 - Multi Core with aXeon E5 2697 v2

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The Xeon E5 2697 v2 @ 3859.1MHzscores getScoreFormatted in the...

 

Edited March 13 by neurotix