Core i7 870 overclocking
First up for this processor, check what your current maximum multiplier values are -- 22. We again fire of a much higher base clock to that multiplier of 22.
As such we were able to overclock the Core i7 870 processor to 4.1 GHz with a Thermalright MUX 120 air cooler. Here's what we did:
- Disable Turbo mode
- Set maximum processor multiplier
- Increase processor voltage a little bit to 1.42v
- Lower QPI ratio (as close as possible to 4800).
- Lower memory multiplier to maximum stable memory frequency
- Increase CPU base frequency
At 4000 MHz on the air cooler we easily booted into windows. We settled at 22x187.5 @ 1.42 Volts. The end result was a stable 4125 MHz.
When we stress the CPU cores with prime 95, temperatures now rise to 79 Degrees C (174F) which really is the maximum limit you want to go to. But ... 4.1 GHz air-cooled is just downright good.
Overclocking itself, it is a pretty easy thing to achieve with this processor. Mind you that overclocking will draw a lot of power from your system. We'll show you that on the next page.
Power Consumption and temperatures
The new Lynnfield based processors have gotten a bit of a redesign and as such they are very energy friendly processors, well -- as long as you do not overclock them.
A processor like the Core i7 870 for example has roughly sometimes even more performance than a core i7 920 yet consumes only 95 Watt, and that is with all cores stressed. Next to that, clever power management allows the internal voltages and processors multiplier to drop, core independent.
All three processors launched today have a TDP of 95W, coming from 130 for the Bloomfield Core i7 series that's quite an improvement and it shows this during our measurements:
| Power Consumption |
idle
|
100% CPU load
|
| Core i5 750 (2,66 MHz) 133x20, |
124
|
154
|
| Core i7 860 (2,80 MHz) 133x21 |
124
|
161
|
| Core i7 870 (2,93 MHz) 133x22 |
124
|
163
|
As you can see, these are very respectable numbers. Mind you that this was done with a P55 motherboard, an SSD, optical drive, 8GB memory and GeForce GXT 280 graphics card.
For the best power consumption make sure you have BIOS features like EIST and CE1 enabled and within Windows set your performance mode to balanced (allows the processor to clock down).
Temperatures are very good as well. With an air cooler you can expect temps like these:
| Temperatures |
idle
|
100% CPU load
|
| Core i5 750 (2,66 MHz) 133x20, |
39
|
52
|
| Core i7 860 (2,80 MHz) 133x21 |
38
|
52
|
| Core i7 870 (2,93 MHz) 133x22 |
38
|
53
|
This was done with a Thermalright MUX 120 air based cooler. Of course results will vary with different mother boards and cooling solutions. But as baseline the temperatures definitely are promising, especially with overclocking in mind.
100% CPU load is 4 cores 100% stressed with Prime 95, voltages are left at default, processor Turbo mode is enabled. Overclocked temps of course will differ, but we'll show you that in a split-second.
Overclocking and power consumption
Okay check this out:
| Power Consumption |
idle
|
100% CPU load
|
| Core i7 870 (2930 MHz) 133x22 |
124
|
162
|
| Core i7 870 (4130 MHz 188x22) 1.425v |
137
|
285
|
What a lot of you do not realize that overclocking a processor can consume heaps of wattage. We put this to the test by monitoring power consumption with the processor in its default setting and then compare to an overclocked 4,1 GHz configuration.
The results are flabbergasting, when we stress the 4 (8 threaded) CPU cores 100% at default (Turbo on) we peak to only 162 Watt for the default clocked Core i7 870.
Once we overclock towards 4.1 GHz ... the power draw all of the sudden is 285 Watt (!) once we stress all CPU cores 100%, so an additional 1200 MHz of power is costing us an additional 123 Watt (!).
Stuff to think about before you start to overclock as the color green turns really red.
BIOS features
Below some example of the BIOS. The BIOS is very much catered for overclocking and offers a really wide varsity of choices.
Standard BIOS welcome screen and to your right the Hardware Monitor
To your right an easy flash function, you can backup and flash from a USB stick. Another trick is fun as well, you can actually boot with the BIOS placed on your USB stick. So would the BIOS completely die after a firmware flash, in theory you can bring the PC back to life.
The Cell menu is where hardcore overcalling will take place. A very wide and extreme set of overclocking and tweaking options will be at your disposal. Everything you need for a successful overlook on the motherboard, CPU or memory is tucked away in here.
Something I like very much, if you favor a certain overclocking profile or setup, you can save and load them, allowing you a little more flexibility to use multiple tweaking profiles.
Next: Hardware and Software Used
------------------------------------ To be continued MSI P55-GD80 review P.4 ---------------------------------------------
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