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CPUs BCLK question

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Hi TPU!
Is it normal to have BCLK slightly over 100, like 100.16?
Also i use hwmonitor in the backround while gaming and it shows my min. clock for CPU is ~4250MHz, so i think my BCLK is hoovering between 98.8-100.16.

Thanks !

http://imgur.com/WbAttxF
 
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Yes. The BCLK will almost never be a precise 100MHz on the dot, however it shouldn't vary under 99 or over 101. Mine normally runs at 99.98MHz.
 

qubit

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Yup, it's normal and is due to small clock speed tolerances in the hardware. Nothing to worry about.
 
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Mine Bclk went up a bit because of the XMP memory profile of my 3000MHz ram.
 
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Yes. The BCLK will almost never be a precise 100MHz on the dot, however it shouldn't vary under 99 or over 101. Mine normally runs at 99.98MHz.
Im not sure if it actually go 98.8, i just calculated hwmonitors 4250MHz reading, 4250/43=98.8
 
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Hi TPU!
Is it normal to have BCLK slightly over 100, like 100.16?
Also i use hwmonitor in the backround while gaming and it shows my min. clock for CPU is ~4250MHz, so i think my BCLK is hoovering between 98.8-100.16.

Thanks !

http://imgur.com/WbAttxF
Completely normal. This is due to spread spectrum which minimizes EMI. It can be disabled if you choose, but not needed. It has nothing to do with clockspeed 'tolerances'. It is 100% intentional.

Bclk should only change, outside of the typical ~1mhz variance, with xmp on x99 with ram 3K+ on some boards. it uses the 125 strap to reach those speeds. z170 has the memory multipliers to reach those speeds so it won't change bclk a SIGNIFICANT amount.
 
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Completely normal. This is due to spread spectrum which minimizes EMI. It can be disabled if you choose, but not needed. It has nothing to do with clockspeed 'tolerances'. It is 100% intentional.

Bclk should only change, outside of the typical ~1mhz variance, with xmp on x99 with ram 3K+ on some boards. it uses the 125 strap to reach those speeds. z170 has the memory multipliers to reach those speeds so it won't change bclk a SIGNIFICANT amount.

I have spread spectrum disabled and my BCLK (or whatever it's called on Z77) is rarely at exactly 100MHz.
 
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Correct. Spread spectrum does not set it at 100MHz it simply stops/starts the fluctuations.

What would actually be considered a 'tolerance' is how the BCLK is derived from the crystal, which is why you don't see 100MHz on the nose. BUt the actual MOVEMENT of the BCLK/FSB is because of spread spectrum on by default to minimize EMI. ;)
 

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Any clock being driven by a PLL is going to always have some level of variation between every cycle and depending on how it is tuned, it very well could just simply run a little under what it's supposed to. It has been my observation that it's much more likely the case that the BCLK will run slightly under what it's supposed to be but, will tend to be relatively consistent. An interesting experiment to try out would be to see if altering the PLL voltage alone causes the bclk to change at all which would be a dead giveaway that it's the PLLs in the CPU that are responsible for this. It's also possible that the 100Mhz BCLK might represent (on some motherboard,) a maximum, on others it might be an average/mean, and on others it might be a minimum. So depending on what the actual hardware characteristics are and how the BIOS has been programmed to interpret that "100.0 Mhz BCLK" setting, could impact what the actual end result might be. Either way, I don't think it's something to worry about. If there was something wrong with clock generation, you would know about it because your system probably either be dead or unstable since (in particular CPUs like ours,) rely on that clockgen for things like PCI-E and DMI between the CPU and the chipset.

tl;dr: It's normal. That setting in the BIOS that says 100.0Mhz BCLK might mean an average, maximum, or minimum (with some other internal constraints,) or it could just be the hardware. Either way, not a cause for concern.
 
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Thanks! I also have speard spectrum already disabled.
 
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Enabled/Disabled, it really doesn't matter where 99.9% of people overclock to. Its only on the extreme end of things where that really matters for stability... that is, unless your PC is sitting next to an extreme high EMI source.
 
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Yes, it's normal as guys above already explained. FSB (now they call it "BCLK") will have some fluctuations, although more than 1% fluctuations are kind of worying. Usually they should be between 99,8 and 100,2.
 
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Nothing to worry about. It is 100 % normal. My own old I7 920 does it aswell. where BLCK is at 195.30 (stock 133.30)



And else try take a look at the image at google. More less all the CPU's have BLCK slightly over or under. Dosent matter if its AMD or intel cpu.

https://www.google.dk/search?q=cpu-...-XQAhWDWBQKHZlzCWAQ_AUICSgC&biw=1920&bih=1031
 
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