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I5-750 can't stablize at 3.5~ghz

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January 6, 2010 2:57:00 AM

After reading the guides here and on other forums, I tried to o/c my pc.

Asus p7p55d evo
Gskill 9 9 9 24 1600 2x2gb
hyper 212+

I disabled ESIT, Turbo, and C1E to start off. Set my BCLK to 175 and multi to 20. QPI to 4.something ghz (can't remember, and running prime95 some more on stock atm). I set my ram to 1440mhz and I manually set the timings.

I set my vcore from 1.2v to 1.3v
IMC to 1.14v
PLL to 1.8v
and left my ram at stock 1.5v

Disabled the spread spectrums and I've tried enabling and disabling LLC. Neither worked. 1-3 cores would fail the Large FTT prime test 1-5 mins in.

Edit: Error msg would be "FATAL ERROR: Rounding was 0.5, expected less than 0.4." From what I gathered, raising vcore would fix the issue but it didn't. My ram passed memtest on stock and o/c'd settings.

On stock, my temps are 25c-55c and when o/c'd, they were 40c-60c.

Any help would be appreciated. Thank you in advance.

More about : 750 stablize ghz

a b K Overclocking
January 8, 2010 1:36:29 AM

Everything sounds OK to start with.
On the average 3.5GHz is a relatively low overclock of this processor.
Have you tried running the ram slower?
How about letting the mobo set the voltages?
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a b K Overclocking
January 8, 2010 3:04:14 AM

enarr said:
After reading the guides here and on other forums, I tried to o/c my pc.

Asus p7p55d evo
Gskill 9 9 9 24 1600 2x2gb
hyper 212+

I disabled ESIT, Turbo, and C1E to start off. Set my BCLK to 175 and multi to 20. QPI to 4.something ghz (can't remember, and running prime95 some more on stock atm). I set my ram to 1440mhz and I manually set the timings.

I set my vcore from 1.2v to 1.3v
IMC to 1.14v
PLL to 1.8v
and left my ram at stock 1.5v

Disabled the spread spectrums and I've tried enabling and disabling LLC. Neither worked. 1-3 cores would fail the Large FTT prime test 1-5 mins in.

Edit: Error msg would be "FATAL ERROR: Rounding was 0.5, expected less than 0.4." From what I gathered, raising vcore would fix the issue but it didn't. My ram passed memtest on stock and o/c'd settings.

On stock, my temps are 25c-55c and when o/c'd, they were 40c-60c.

Any help would be appreciated. Thank you in advance.

odd...

Have you tried 1.10V on PCH?
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January 8, 2010 3:34:51 AM

I've gotten it to stabilize by increasing my ram voltage to 1.65v from its stock of 1.5v. I tried to o/c it to 3.8ghz to test it some more. 20x190 @ 1.35vcore, CPU VTT @ 1.225, PLL @ 1.8, Dram @ 1.65. I was able to run prime95@large FTT without getting errors for 10+ mins but cpus were at 80~c, so I stopped. I tried lowering voltages little by little but it wouldnt stabilize. Going to give it a rest for now.
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a b K Overclocking
January 8, 2010 9:14:01 PM

enarr said:
I've gotten it to stabilize by increasing my ram voltage to 1.65v from its stock of 1.5v. I tried to o/c it to 3.8ghz to test it some more. 20x190 @ 1.35vcore, CPU VTT @ 1.225, PLL @ 1.8, Dram @ 1.65. I was able to run prime95@large FTT without getting errors for 10+ mins but cpus were at 80~c, so I stopped. I tried lowering voltages little by little but it wouldnt stabilize. Going to give it a rest for now.

DDR3 is very picky and requires people to set the timing and voltage manually ACCORDING to the manual.

I thought you got one of the low voltage RAMs from G.skill as you stated its stock is 1.5V.

FYI, most of the 1333MHz+ DDR3 RAM require 1.65V which is the Absolute Maximum specification and it could potentially damage your MB according to Intel.

BTW, my 1600MHz ram is also set to 180x8=1440 and its voltage is at 1.568V which is lower than the Maximum specification, 1.575V.
(p.s. More than 14hours Memtest86+ stable)

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