Is a small BCLK overclock a bad idea?

[techne]

I did a BCLK overclock two years ago, when I bought this i7-4771: just to see how far it would go. The OC lasted just a day or two. Then I went back to the stock values and forgot anything related to OC. After all, Intel has forced me to choose... and I chose a non-K CPU.

I know I can, with a very small BCLK OC (2.6%), obtain 100MHz more and reach 4GHz (turbo). The RAM I have would support it easily (from 1866 to 1915 MHz), and I doubt that the VGA would complain.

But I really don't like the idea of bumping the frequency of SATA discs and other PCI-E cards. I think this small OC is a bad idea. I think I will gain too little and risk too much. Am I wrong?

 

[nerp]

Not worth it. 100mhz increase won't be noticeable at all. And if you get a crash or weird glitch, you'll never know if its the OC or not. Best to not OC and be able to rule that out. I'm not anti-overclocking but it just doesn't seem worth it in your case.

 

[Batmeat]

The performance increase of 100mhz is not worth it for you. In the future if you decide to get into overclocking, make sure you get a motherboard that supports frequency adjustments that will auto correct the other lanes your devices are hooked too.

 

[Sheep221]

Sandy Bridge, Ivy Bridge and Haswell are BCLK-overclocking locked, the highest reported safe BCLK increase was 106 MHz before hardware failure occurs, most common were data corruption followed by damaged HDDs and lastly killed motherboard. So not really sure if you will do anything with BCLK but you can still overclock 4 bins over max turbo on your CPU multiplier so going for 4.3GHz is max you get from it without touching the BCLK.

 

[StrangerGuy]

Sandy Bridge, Ivy Bridge and Haswell are BCLK-overclocking locked, the highest reported safe BCLK increase was 106 MHz before hardware failure occurs, most common were data corruption followed by damaged HDDs and lastly killed motherboard. So not really sure if you will do anything with BCLK but you can still overclock 4 bins over max turbo on your CPU multiplier so going for 4.3GHz is max you get from it without touching the BCLK.

http://techreport.com/news/24950/intel-removes-modest-free-overclocking-from-standard-haswell-cpus

There is no +400MHz free OC on non-K from Haswell onwards.

Also a 2.6% OC is incredibly pointless relative to the risks of instability.

 

[Flapdrol1337]

Yeah, I wouldn't risk it.

 

[techne]

As it seems, that was an easy question. Thank you all. :thumbsup:

I'm still learning the BIOS options of the Z97 Deluxe motherboard; it's a sophisticated lady... Being an ASUS board, it uses the option "Sync All Cores" by default. With this option ON, I have only ONE Max Turbo Boost Multiplier for all cores: 39x.

Well, I tought "sync all cores" was cool... Then I read this guy (kougar) at another forum:

I thought it was cool until I realized how much extra voltage it was using just for that paltry 200Mhz boost

And now I'm tempted to disable even the option "Sync All Cores"...

 

[Sheep221]

http://techreport.com/news/24950/intel-removes-modest-free-overclocking-from-standard-haswell-cpus

There is no +400MHz free OC on non-K from Haswell onwards.

Also a 2.6% OC is incredibly pointless relative to the risks of instability.

Ah right guess my info has been well out of date, thanks for correction.

 

[Yuriman]

As it seems, that was an easy question. Thank you all. :thumbsup:

I'm still learning the BIOS options of the Z97 Deluxe motherboard; it's a sophisticated lady... Being an ASUS board, it uses the option "Sync All Cores" by default. With this option ON, I have only ONE Max Turbo Boost Multiplier for all cores: 39x.

Well, I tought "sync all cores" was cool... Then I read this guy (kougar) at another forum:

And now I'm tempted to disable even the option "Sync All Cores"...

You might consider fiddling with voltage. At stock speeds, I was able to shave 25w off of my CPU's power consumption under heavy loads, which significantly cut down on heat and noise. Intel's voltage tables are very conservative.

 

[TeknoBug]

My i5 3550 can OC to 3.9GHz via multiplier then I can do 102.78 BCLK and push it to 4GHz but honestly not worth it when it OC's the HDD, memory, chipset, GPU all at the same time.

 

[freeskier93]

As it seems, that was an easy question. Thank you all. :thumbsup:

I'm still learning the BIOS options of the Z97 Deluxe motherboard; it's a sophisticated lady... Being an ASUS board, it uses the option "Sync All Cores" by default. With this option ON, I have only ONE Max Turbo Boost Multiplier for all cores: 39x.

Well, I tought "sync all cores" was cool... Then I read this guy (kougar) at another forum:

And now I'm tempted to disable even the option "Sync All Cores"...

Have you actually looked to see how much voltage you're running at full boost? Also, an extra 200Mhz across 3 cores isn't what I would consider paltry.

I have my E3 1231v3 set to turbo boost all cores to 3.8 and voltages are fine. Even under full load I haven't seen it hit its rated 80 watt TDP.

 

[techne]

You might consider fiddling with voltage. At stock speeds, I was able to shave 25w off of my CPU's power consumption under heavy loads, which significantly cut down on heat and noise. Intel's voltage tables are very conservative.

I'll try the following: "Sync All Cores" + set manually in the BIOS the lowest working CPU voltage.

Also, an extra 200Mhz across 3 cores isn't what I would consider paltry.

Actually, the truth is somewhere in the middle. Take a look at the stock (Intel) multipliers:

Max Turbo Boost Multipliers 1C: 39x, 2C: 39x, 3C: 38x, 4C: 37x
So, when running all cores with a 39x multiplier, there's only a 100MHz extra boost in the third core and a 200Mhz extra boost in the fourth core.

 

[techne]

Here are the results (CPU-Z):

CPU IDLE:
Core #0 Multiplier = x8 (800Mhz), Core voltage = 0.703 V

CPU (SYNC ALL CORES DISABLED) running HyperPi:
Core #0 Multiplier = x37 (3700Mhz), Core voltage = 1.134 V

CPU (SYNC ALL CORES ENABLED) running HyperPi:
Core #0 Multiplier = x39 (3900Mhz), Core voltage = 1.201 V

There's indeed a boost in the core voltage when using "Sync All Cores", but it seems to be small and harmless...

(I can't understand why the Core #0 can run (in Turbo Mode) with a x37 multiplier, when it's supposed to run with a x39 multiplier...)

 

[freeskier93]

I'll try the following: "Sync All Cores" + set manually in the BIOS the lowest working CPU voltage.


Actually, the truth is somewhere in the middle. Take a look at the stock (Intel) multipliers:

Max Turbo Boost Multipliers 1C: 39x, 2C: 39x, 3C: 38x, 4C: 37x
So, when running all cores with a 39x multiplier, there's only a 100MHz extra boost in the third core and a 200Mhz extra boost in the fourth core.

Those are the maximum multipliers for a given number of active cores, not the multipliers for each core under full load.

When 1 core is active it can run at a max of 3.9Ghz, with 2 cores active they can both run at a max of 3.9Ghz, with 3 cores active all 3 can run at a max of 3.8Ghz, and with 4 active cores all 4 can run at a max of 3.7Ghz.

So you're actually gaining 200Mhz across all 4 cores when under full load.

 

[techne]

Those are the maximum multipliers for a given number of active cores, not the multipliers for each core under full load.
When 1 core is active it can run at a max of 3.9Ghz, with 2 cores active they can both run at a max of 3.9Ghz, with 3 cores active all 3 can run at a max of 3.8Ghz, and with 4 active cores all 4 can run at a max of 3.7Ghz.
So you're actually gaining 200Mhz across all 4 cores when under full load.

Yes. That's right. And that's why I was not understanding my own numbers (in my previous post). Thank you.

So I'm gathering conclusions and we are approaching the end of this thread:

[1] 100% of the posters (including myself) think that a small BCLK overclock is a bad idea; unless...

you get a motherboard that supports frequency adjustments that will auto correct the other lanes your devices are hooked too.

[2] On the other hand, the "Sync All Cores" option actually increases the Core Voltage, but to a limit that seems very safe (1.201 V); and

you're actually gaining 200Mhz across all 4 cores when under full load.

[3] I forgot to mention in the last post, but the "Sync All Cores" does not affect the IDLE values (Core #0 Multiplier = x8 (800Mhz), Core voltage = 0.703 V).

So, it seems that the "Sync All Cores" is a very welcome option offering the best of two worlds: energy saving and (when needed) more horsepower.

==edit==

If the conclusions above are correct and no one has nothing more to say, the moderators may close this thread at their discretion. Thank you all!

 

[Heatshiver]

Agree with what most said here, no point really. I was able to push a Ivy Bridge 200MHz on a locked multiplier. Helpful? Not really, did fine without it for everything I tried with it.