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***The Official Core i5 Overclocking Thread***

Interesting.

My i5 750 system became unstable over the last few weeks despite being at the same settings with no hardware changes since 2009.

After a spree of random system restarts while I was using it I tested the memory and ran LinX.

15000 errors in memtest later I decided that was a fail.
Same for LinX erring between 33 and 57 seconds in every time.

It was at:

160 x auto = variable up to 3360MHz
+ Turbo
+ Speedstep

CPU volts @ 1.20000V
CPU PLL @ 1.80200V
IMC volts @ 1.11300V
DRAM @ 1.60325V

The new settings are:

CPU volts @ 1.20000V
CPU PLL @ 1.80200V
IMC volts @ 1.12625V (+1 notch up)
DRAM @ 1.60325V

Ran 50 passes of LinX over an hour and a bit as well as a pass of memtest.

Seemed odd that it would fail an overclock of 25% after 2 years stable :confused:
 
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Yeah, it does seem strange indeed. It looks like the memory is degrading?

On the other hand it could be just on the borderline of stability, it's not uncommon chips to require a little more voltage over time. It's not a large increase by any means so I wouldn't worry too much.

I recently got my i5 750 stable at 4GHz (which seemed impossible before) but it's on the borderline of stability when with power savings on it randomly crashes in movies. :(

So almost two years in and I watercooled it just yesterday. Finishing off the leak test now and am going to find if lower temps help overclocking tomorrow.
 
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Oh now it's trolling me.

I set it back to the original settings and it did a 5 hour, 250 pass in LinX.

When I redid the settings I started from a reset bios so it may have been that some other setting was toggled which was causing the instability.

Puzzling.
 
System instability started another round of OC testing.

Same 3.4GHz OC but now the settings are:

160 x auto = variable up to 3360MHz
+ Turbo
+ Speedstep
+ Load Line Calibration

CPU volts @ 1.15625V (seven notches down from the 1.2 it was at)
CPU PLL @ 1.80200V
IMC volts @ 1.11300V
DRAM @ 1.60325V

The memory incidentally is 4GB DDR3 1600MHz 7/7/7/24.

Set it going in LinX while I was at work, came back and it was fine for almost 10 hours before I stopped the test:

tmpu.jpg


I don't actually use that asus thing for adjusting OC but its the only program I have that shows all voltage and multi settings outside the BIOS. It agrees with all the settings incidentally except the CPU voltage, it would rather it was at 1.2V.
 
just for the record what I'm running

Intel Core i5-2500K
Kingston HyperX Blu PC3-10666 C9
Asus p67p8 m pro
Corsair TX650 V2

Settings for bios
AI OC Tuner - Manual
BCLK - 100
Turbo Ratio - 47
Internal PLL OV - Auto
Mem Freq - Auto
DRAM Timing - Auto
Offset - (+)
CPU Offset V - 0.005
DRAM V - Auto
VCCIO - Auto
PCH - Auto
LLC - Enabled
Spread Spectrum - Enabled
CPU Ratio - Auto
EIST - Enabled
Turbo Mode - Enabled
Additional Turbo V - 0.004
C1E - Auto
C3 - Auto
C6 - Enabled

Runs my vcore at a fairly solid 1.4v and I think I could probably ramp the ratio up a little more but going to need better cooling first. Also left it for 6 hours in prime with no errors if these setting help anyone with the same board as you can't manually set the vcore :(
 
Hotwired, I only run prime95 now, IBT is only good if you want to quickly test some settings, if they crash or not.

Long term stability should be tested with prime95 blend, it stresses CPU and RAM (in this case - IMC) equally and that is what you want to achieve.

I would also check voltages in CPU-Z, both in idle and under load as they can vary greatly depending on your mobos vdroop and vdrop. I use a multimeter when overclocking on the borderline of safety.
 
I use IBT/LinX because it shows up a dodgy OC much much faster than Prime95.

I'll set up Prime95 to run when I go to sleep, see if it reckons any different :)

Had a system crash while running Prime, retested with memtest, found one error, increased IMC by one notch, passed memtest clear again.

Prime for best part of 10 hours:

tmpma.jpg
 
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JUst got my i5 750 but this thread baffles me why are people thinking 5 passes of IBt is enough ? and nobody runs it correctly ? you are supposed to select custom and set the free ram you have and run it 50 times at least.I say this because you can see if you select various ram amounts the G/Flops per second can vary.


So are people still sticking to the intel specs ?
 
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C64 said:
JUst got my i5 750 but this thread baffles me why are people thinking 5 passes of IBt is enough ? and nobody runs it correctly ? you are supposed to select custom and set the free ram you have and run it 50 times at least.

So are people still sticking to the intel specs ?
Click to expand...

People who are serious about it being stable will do a long test (someone was doing a 72h one a few pages back), people who are not will do short ones for whatever reason, perhaps they just want a benchmark screenshot for the forum, not an uncommon reason :p

If you're not looking to push the limits of your chip there's no need to go above the intel specs.
 
Hotwired said:
People who are serious about it being stable will do a long test (someone was doing a 72h one a few pages back), people who are not will do short ones for whatever reason, perhaps they just want a benchmark screenshot for the forum, not an uncommon reason :p

If you're not looking to push the limits of your chip there's no need to go above the intel specs.
Click to expand...

erm this is an overclocking forum and an i5 overclocking thread I'd imagine everyone in this thread is looking to go over intel specs

I just decided I'd stick to vtt and pll etc on auto and core voltage at 1.35 and top that out so far looking like 3.9 ghz ish.
 
C64 said:
erm this is an overclocking forum and an i5 overclocking thread I'd imagine everyone in this thread is looking to go over intel specs

I just decided I'd stick to vtt and pll etc on auto and core voltage at 1.35 and top that out so far looking like 3.9 ghz ish.
Click to expand...

These are the intel specs:

vtt.jpg


No ones posted any settings above that in the thread.
 
This is what i got thus far pretty good for under 1.35 volts all other voltages are on auto ram on 1.64 I put IBT on high as i had just over 2000 mb free ram
is it normal for these to not undervolt with speedstep on ? cpu-z 64 reports voltage remains the same when the multi goes down ?

Capture2.jpg

Capture-6.jpg
 
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