My i7 870 is 3.52ghz at stock?

glenimp617

glenimp617

glenimp617

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Installed my new i7 early today and was surprised to see it boot at 3.52ghz. I set my bios to defaults and made sure everything was on auto.

The temps are around 37ish sat in windows doing moderate tasks, CPU load was 25%. I am currently running all cores at 100% now and have been for the last couple of hours. Everything seems ok, CPU fan hasn't kicked up a gear so I can only assume everything is ok. Have to admit the thing is really flying, my x264 encoding is hitting just over 30fps lol my i5 only managed 18fps

Just wondering why it's running faster than normal?
 
Sounds like Turbo boost has kicked in, what does CPU-Z show.

It may be a possibility the motherboard has set a higher multiplier, cpu-z should show this.
 
Are you certain that the CPU was still sitting at 3.52GHz when you were doing the 100% load tasks, not just when it was sitting relatively idle in windows?

This sounds like Intel Turbo Boost, when the CPU is running below its current, thermal and power limits it can dynamically increase it's multiplier (default of 21) by 1/1/4/5 - depending whether all four cores (+1 multi) are loaded or just one (+5 multi).

In the situation you describe you are most likely only running software that is only taxing one core - so the multipier will be increased by 5 to a total of 26. 26 X 133.33MHz (default bus speed) = 3.466 GHz.

If you try loading your CPU with something that stresses all 4 cores, then it should only go up to 2.93GHz.

Have you considered overclocking your CPU? The i7 860 is a very overclockable CPU and the performance benefits in CPU hungry programs like video encoding are substantial.
 
I don't think it would show that in the BIOS if it was caused by turbo mode.

What does the bios say the base clockspeed (BCLK) and CPU multiplier are set to?
 
ok, came down this morning to find the PC on, fans still going around but nothing on the screen. Keyboard was also dead.

Rebooted and went into the BIOS. No idea why but the CPU is now saying 3.84ghz

CPU Multi - 22
BLK - 160Mhz (seem to think this should be 133Mhz)
RAM was runnning at 1920mhz which set alarm bells ringing

I set BIOS defaults and rebooted (did this yesterday). Now the BLK is set to 133Mhz and RAM at 1066. The RAM I have is 1600Mhz anyway so I set the XMP Profile to 1 Standard so it went back to 1600Mhz

Thought since the ram was running so high I'd maybe try to get the CPU back up to 3.5ghz whilst leaving the RAM at 1600mhz. Don't know if this is right, but I set the BLK back to 160 which made the RAM jump back to 1920 so I changed the RAM setting from 12 to 10 so it now reads 1600 again.

Booted back into windows and now stressing the CPU

Have I done right or wrong?
 
Yea, the default BCLK is 133MHz - so that must have been the reason for the extra speed.

I suggest you immediately go back into the BIOS and set the CPU core voltage manually (something like 1.20V should be fine) - as if you leave it on AUTO (default) it will increase the voltage with the BCLK which is very bad.

What you have done with the RAM is exactly what you should do - just check it is still running at the same timings and voltage (should be ~1.65V).

Finally, I would also strongly suggest you turn off Turbo mode now you are overclocking. It is nice if you are just running at stock, but if you set up an overclock just right you don't want the CPU magically overclocking itself further when it wants (as it can cause instability).

What CPU cooling have you got?
 
Thanks for your help

I've tried a few things out this morning. Currently on the following:

CPU Multi: 21
BLK: 181
SPD: 8

CPU: 3.8Ghz
RAM: 1440Mhz

Turbo: Off
CPU Volts: 1.3V
CPU ???: 1.25V

My cooler is the Akasa Freedom with some AS5
 
Cool, how are the temps at 100% load? (use a stress test program like occt for this).

As for the CPU voltage, i'm not sure what the Lynnfield cores need to keep 3.8GHz stable, but I would suggest stress testing it at 1.3V for an hour or so, if that remains stable then reduce the cpu voltage in stages (with more stress testing after each stage) until you find the lowest stable CPU voltage.
 
Thanks very much for your help. Hopefully I can get a stable system as on 3.8ghz my x264 encoding times are amazing. Over 30fps!!!!!

ok I had a blue screen when changing the volts from auto so I have achieved the following so far

Intel say the max volts for the Lynnfields are 1.55v on the core and 1.21v on the qpi/vtt. Most review sites seem to stick to 1.4v though

Multi: 21
Blk: 180
Spd: 8

Cpu: 3.78Ghz
Ram: 1440Mhz

CPU Volts: 1.4v
Qpi/Vtt: 1.21v

so far, with these settings everything is ok. Just been maxing the cpu out and it hasn't crashed so far. Temps were 57c IIRC
 
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I'm quite enjoying this :D

Now at 3.9ghz but had to drop the RAM to 9-9-9-24

seems ok so far but I'm stress testing now. Based on that outcome I'll most likely start to drop the volts
 
Stanners said:
I would be careful with the cpu volts, i think you should try to stay under 1.3v's
Click to expand...

according to intels revised tech sheets, the safe limits are 1.4v on the core and vtt. 1.8v on the dimms.

Now running at 3.8ghz stable 1.4v vore and 1.21 vtt

Now it's stable I'll start to drop the volts
 
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