My overclock results. i5 2500k, golden chip?

[Diesel722]

Its been awhile since I've been active in these forums. I was running my old system for about 3 years and finally got around to doing an upgrade. So far my i5 2500k cpu on an Asus P8P67 Pro has been overclocking extremely well.

I was amazed to get 4.8GHz at only 1.3v, ran Prime95 stable for 8 hours two nights in a row. ~28c idle, maxed between 64c-74c full load (a little concerned about the 10c temp difference between cores)

I bumped up to 4.9GHz and 1.325v and am now 8 hrs Prime95 stable at that setting. ~30c idle, maxed between 70c-80c full load (again, 10c difference between the same cores as above)

I think this chip could easily do 5Ghz and maybe even 5.2GHz at acceptable voltages but I unfortunately my temps are getting a little too high for me to feel comfortable at those speeds.

I use Coolit Eco CPU Water Cooling System and right now I only have 1 stock fan on the radiator pushing air from outside the case and exhausting out the top 200mm case fan (Case = Coolermaster Haf X) but I'm looking to get two Scythe Gentle Typhoon 120MM 1850RPM 58.3CFM in a push/pull configuration and hopefully that will help lower temps so I can clock to 5GHz and maybe even more.

My settings:
Turbo Ratio - 49
Internal PLL Voltage - Enabled
Load-Line Calibration - Ultra High
VRM Frequency - 350
Phase Control - Extreme
Duty Cycle - T.Probe (also tried extreme but thought T.Probe would help stabilize differences in core temps, doesn't seem to make a difference)
CPU Current Capability - 110%
VCCSA - 0.924
VCCIO - 1.05
CPU PLL - 1.8125V
EIST and C-States enabled (been trying both enabled and disabled, doesn't seem to make any difference so leaving enabled for now)

I had absolutely no luck overclocking my memory speed OR timings so I'm still running memory at stock settings (Corsair CMZ8GX3M2A1600C9 Vengeance 8GB 2X4GB DDR3-1600 CL9-9-9-24 Dual Channel Memory Kit)

Another concern I have is I am getting very low Physics score on 3dmark11 (~5200 performance setting) I tried disabling c-states and it didn't help my score. I think it might be my firewall (Comodo) I found other people having the same issue using this firewall because strangely it seems to limit cpu usage for x64 applications. Haven't found a fix yet, may have to switch firewalls.

I guess I'm posting this so other i5 2500k owners can get an idea what the latest chips are capable of. Any advice or feedback on my settings would be appreciated.

 

[EarthDog]

Solid chip!! The thing with memory on SB is the jumps are so drastic (1600->1833) and most ram doesnt overclock that far, especially already being at 'high' 9-9-9 timings.

 

[SHODAN]

EarthDog, cannot the main clock be varied by about 10% (+/- 5%) on Sandy Bridge boards? I would think that could allow one to get between RAM speed settings, but there must be a reason you did not suggest this. What is it?

 

[Theocnoob]

Its been awhile since I've been active in these forums. I was running my old system for about 3 years and finally got around to doing an upgrade. So far my i5 2500k cpu on an Asus P8P67 Pro has been overclocking extremely well.

I was amazed to get 4.8GHz at only 1.3v, ran Prime95 stable for 8 hours two nights in a row. ~28c idle, maxed between 64c-74c full load (a little concerned about the 10c temp difference between cores)

I bumped up to 4.9GHz and 1.325v and am now 8 hrs Prime95 stable at that setting. ~30c idle, maxed between 70c-80c full load (again, 10c difference between the same cores as above)

I think this chip could easily do 5Ghz and maybe even 5.2GHz at acceptable voltages but I unfortunately my temps are getting a little too high for me to feel comfortable at those speeds.

I use Coolit Eco CPU Water Cooling System and right now I only have 1 stock fan on the radiator pushing air from outside the case and exhausting out the top 200mm case fan (Case = Coolermaster Haf X) but I'm looking to get two Scythe Gentle Typhoon 120MM 1850RPM 58.3CFM in a push/pull configuration and hopefully that will help lower temps so I can clock to 5GHz and maybe even more.

My settings:
Turbo Ratio - 49
Internal PLL Voltage - Enabled
Load-Line Calibration - Ultra High
VRM Frequency - 350
Phase Control - Extreme
Duty Cycle - T.Probe (also tried extreme but thought T.Probe would help stabilize differences in core temps, doesn't seem to make a difference)
CPU Current Capability - 110%
VCCSA - 0.924
VCCIO - 1.05
CPU PLL - 1.8125V
EIST and C-States enabled (been trying both enabled and disabled, doesn't seem to make any difference so leaving enabled for now)

I had absolutely no luck overclocking my memory speed OR timings so I'm still running memory at stock settings (Corsair CMZ8GX3M2A1600C9 Vengeance 8GB 2X4GB DDR3-1600 CL9-9-9-24 Dual Channel Memory Kit)

Another concern I have is I am getting very low Physics score on 3dmark11 (~5200 performance setting) I tried disabling c-states and it didn't help my score. I think it might be my firewall (Comodo) I found other people having the same issue using this firewall because strangely it seems to limit cpu usage for x64 applications. Haven't found a fix yet, may have to switch firewalls.

I guess I'm posting this so other i5 2500k owners can get an idea what the latest chips are capable of. Any advice or feedback on my settings would be appreciated.

Is 325 your default VRM frequency? Also did you manually alter VCCSA and IO or were they auto'd to those settings? Does the system maintain stability if you set the current capability to 100 or only if it's 110?

You have a really sweet OC given the low voltage. Definitely a good chip!.

 

[Diesel722]

Most of my settings I made based on various i5 2500k overclock guides and not so much trial and error on my part.

I think default VRM Frequency was 300. I changed it to 350 based on recommendations of an "ASUS Technical Marketing Specialist" on hardforum. He said 350 was the best setting for sustaining stability at multis of 48x or above especially for running unrealistic loading testing such as prime or linx. I never tested stability at 300 I just took his word for it since my multi is 48x or 49x (still haven't tried above that yet)

I raised my current capability to 110% to avoid any artificial limiting of my high overclock once again based on suggestion.

I manually entered VCCSA and VCCIO voltages instead of leaving it set to auto to remove the board's ability to over-volt it at high clock speeds (which it does do, according to the clunk guide)

CPU PLL was dipping below 1.8V so I compensated by increasing the CPU PLL to 1.8125V

So yeah, I admit I am relying pretty heavy on the guides but their suggestions have worked out very well for me. I'm sure my overclock would still be stable if I left those settings default. The changes are minor but add a little more stability.

For 24/7 use I'm sticking to the 4.8GHz @ 1.3v for now but I will shoot for 5GHz sometime in the near future.

 

[EarthDog]

EarthDog, cannot the main clock be varied by about 10% (+/- 5%) on Sandy Bridge boards? I would think that could allow one to get between RAM speed settings, but there must be a reason you did not suggest this. What is it?

There is VERY limited bclk changes (think 1,2,3 nclk) on SB based boards is the reason why. Sometimes you cannot use the bclk at all, so you are limited to the memory multipliers.

 

[CompuTamer]

If i remember correctly, the clock can only be varied by what the SATA and USB busses can manage, which is mainly limited by the whatever is connected to them, right?

 

[EarthDog]

I have to admit Im not sure what the limitation is. But like past generations, I believe the sata and USB have nothing to do with it...Im just not sure though.

Remember in past gen's it was pcie frequency that borked sata lanes. Ive never heard of USB overclocking with bclk though.

 

[deathman20]

I have to admit Im not sure what the limitation is. But like past generations, I believe the sata and USB have nothing to do with it...Im just not sure though.

Remember in past gen's it was pcie frequency that borked sata lanes. Ive never heard of USB overclocking with bclk though.

USB overclocking is new to me. PCI-E though, yup say up to 105-110Mhz for using onboard Raid, 115Mhz for GPU's any higher and you'd have more issues of the GPU not working typically. Though this was back a few years. Now PCI-E I don't take over 103Mhz currently just in fear of what effect it would have on SSD's. Mech drives could handle much higher upwards of 120Mhz+ as long as the GPU could handle it, course not raided.

 

[Knufire]

From what I've read, it's the PCIe bus limiting the BLCK. May or may nt be true.

On the topic of increasing it, someone on these forums discovered OCing the PCIe bus gave a linear gain in speed on a Revodrive in ATTO.

 

[randomwhiteguy]

I have the i5-2500k as well on a Gigabyte z68 board and I had mine OC'd to 4.8, using stock heat sink and fan, according to core temp i was idling and doing small tasks anywhere from 40-55c but on prime95 it shot up to 75-80c on full load so I decided to cut out the OC till I upgrade the cooling. These chips OC so easily and stay so cool. Not to mention they are blazing fast doing just about everything, (atleast what I do).

 

[ibewok]

Could it be possible that the "golden chip" had a twin separated at birth??

I just got an i5 2500k from a friend of a friend (most likely not an overclocker) and it's running 4.7ghz @ 1.3v as well. I haven't done a full 8 hours of prime but so far after doing 30min of "torture blend" I'm only hitting temps of 63-64c under a megahalem push/pull

I only changing voltage to "1.3v fixed" and "LLC spread 4" and just kept increasing CPU multi and here I am now staring at the magical 5ghz. The absolutely most awesome part is all my fans (case/cpu) are on medium settings.

Here's my setup:
here my setup:
i5 2500k
Asrock Z77 Extreme4
Megahalem rev B push&pull (antec tri-cool set to medium)
Fractal R4 (3x140mm intake & 2x140mm exhaust)
other crap
ATI 4870
128 Crucial M4 SSD
kingston hyper X DDR3 1600 @ 1333 @1.50 (meh?)

Does an agressive LLC (stage 4) have any negative affect on a high overclock?