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Strange overclocking values for i5 750 2,67 when updating BIOS

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January 22, 2011 10:30:59 AM

Hi!
I recentley updated my BIOS version from 1.1 to the 1.9 version, then when I restarted the system the CPU fan ran at maximum speed so I went back in to the BIOS and set the "CPU smart fan target" to 40 and the minimum fan speed became 62,5%, it reduced the noise so no problem there (idle were now at 32 degrees for CPU), but what I discovered was that the CPU clock frequency was changed to 3,2 GHz and the "Turbo boost" was enabled, under the memory-z catigory the x.m.p (or something like that) was enabled to let the corsair memory (2*2gb) reach max value of 1600 MHz.

What I could not do was keep the default CPU clock value (at 2,6 GHz) and still have 1600 MHz in each memory, it was either lowering the memory to 1333 MHz by turning of x.m.p and turning of Turbo boost so I could achieve the default 2,67 GHz, or turning on the x.m.p so I could reach 1600 Mhz but then it automatic changed the CPU frequency to 3,2 GHz.

So my question is how can I keep the memory at 1600 MHz and the CPU clock value at 2,67 GHz? is it even possible with BIOS 1.9? (because it was possible with the 1.1 version)

F.y.i the CPU-Z program is showing the clock value 3,6 Ghz!! it was not my intention to overcklock it:p 

Thanks in advance!
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a b K Overclocking
January 22, 2011 10:38:29 AM

zato said:
Hi!
I recentley updated my BIOS version from 1.1 to the 1.9 version, then when I restarted the system the CPU fan ran at maximum speed so I went back in to the BIOS and set the "CPU smart fan target" to 40 and the minimum fan speed became 62,5%, it reduced the noise so no problem there (idle were now at 32 degrees for CPU), but what I discovered was that the CPU clock frequency was changed to 3,2 GHz and the "Turbo boost" was enabled, under the memory-z catigory the x.m.p (or something like that) was enabled to let the corsair memory (2*2gb) reach max value of 1600 MHz.

What I could not do was keep the default CPU clock value (at 2,6 GHz) and still have 1600 MHz in each memory, it was either lowering the memory to 1333 MHz by turning of x.m.p and turning of Turbo boost so I could achieve the default 2,67 GHz, or turning on the x.m.p so I could reach 1600 Mhz but then it automatic changed the CPU frequency to 3,2 GHz.

So my question is how can I keep the memory at 1600 MHz and the CPU clock value at 2,67 GHz? is it even possible with BIOS 1.9? (because it was possible with the 1.1 version)

F.y.i the CPU-Z program is showing the clock value 3,6 Ghz!! it was not my intention to overcklock it:p 

Thanks in advance!

It's not possible to run 750 and RAM at 2.64GHz and 1600MHz respectively, because they are both tied to BCLK.
January 22, 2011 3:18:14 PM

ok, but is it possible to lower the frequency from 3.6 GHz? and if how?
I see that you have the same CPU and clock value, do you experience any problems or issus with such high value?
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a b K Overclocking
January 23, 2011 4:01:17 AM

zato said:
ok, but is it possible to lower the frequency from 3.6 GHz? and if how?
I see that you have the same CPU and clock value, do you experience any problems or issus with such high value?

1) By disabling Turbo Boost Technology in your BIOS.

2)
CPU-Z should shows 3849MHz instead according the information given by you which implies that your BCLK=160MHz.
It must be down clocked to 3.6GHz automatically due to overheating.

3) Your case is different from mine! My 750 runs at 3.6GHz on all cores, while your one would only runs at similar frequency only when 2 or less cores active.
January 24, 2011 12:33:38 PM

thanks! that helped alot, now its on 3.2 GHz, how do one keep that on all four cores?
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a b } Memory
January 24, 2011 3:38:02 PM

Manually set bclk and multiplier for CPU. verify memory ratio @ 2.5

On my i5-750 (Uses ddr3-1600 CL7) I set the bclk to 200 MHz and my multiplier to 16 for 3.2 GHz (I bumped up the cpu voltage to 1.2 volts so I could run at 3.8 MHZ simply by increasing the multiplier to 19). Note multiplier set to 14 equals 2.8 close to stock, and multiplier of 15 would yield 3.0 MHz.

Reason I like the 200 MHZ bclk is for the memory.
1 to 2 ratio (200 x2 = 400) - sychronous mode
DDR2 or 3, 400 x 2 (clk on both leading and lagging edge of clk pulse)= 800
Dual channel - 800 x 2 = 1600

for a bclk of 160 the ratio has to be 1 to 2.5 to equal the 400 (assychronous mode)
In my bios for the Memory I selected use XPM and profile 1 which set memory voltage, Ratio, and CL values correctly and set my bclk to 160 which I then changed to 200

Added, I disabled turbo boost so that all four cores stay at the selected value
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January 25, 2011 6:43:03 AM

zato said:
thanks! that helped alot, now its on 3.2 GHz, how do one keep that on all four cores?

MANUALLY set your BCLK to 160 and memory multiplier to 10x in BIOS. Done!
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January 25, 2011 6:49:20 AM

Quote:
why you want to do that? Turbo boost works great on those chips

To avoid some cores wearing out faster than the rest which MIGHT cause instability.
!