Overclocking

Overclocking

The LANShark comes factory overclocked to 3.6GHz.  This factory OC from stock 3.2 GHz to 3.6GHz looks to be pretty mild, not much hot sauce, but not as tasty as the 4+ GHz from some of the other i7 965s and i7 975s weve looked at.  We could get this i7 965 to boot at 3.875GHz, but we noticed the thermal protection was kicking in and throttling the chip down to 3.2 to 3.4GHz with Prime95. 

For the record, lets look at CPU-Z to see the factory overclocked 3.6GHz settings:

The Core i7 965 is multiplier unlocked, so a very mild bump to 27x is very safe without overtaxing the cooling.

Initially, the Gene chose 9-9-9-24 for timings at 1600MHz.  For the benchmarks we adjusted this down to a better 8-8-8-24 and didn't really touch the memory afterwards.

For gaming is not like Prime95, so we left it at 3.875GHz for the overclocking results.  I'll let CPUID tell the story here:

Temperature

We loaded up the LANShark with Prime95 and used Everest Ultimate to record temperatures for about 30 minutes in 5 second intervals.  At 3.6GHz, the system ran on the warm side, around 70C, but not too bad.  Here is a shot of the 3875.5 MHz OC run:

The settings were 3.875.5GHz OC on the CPU to see how the cooling system could handle it.

This graph contains a lot of data, so let me explain.  Starting at zero, from front to the back, the first eight lines are CPU utilization.  Behind that are the CPU package and Motherboard temperatures in Celcius, starting at about 30C and 25C respectively.  The next group behind are the ever important core temperatures, starting at 41C idle, and on the back wall is the CPU power in watts.

This test is usually 30 minutes, taken in 5 second intervals with Everest Ultimate, however this one only went 23 minutes due to a BSOD.  As you can see, and I do apologize if the graph is not too clear, once load is applied, the CPU heats up rapidly to about 70C.  From there two things happen, one is the CPU is immediately throttled to 3.2 to 3.4GHz, standard operating range for the i7 965, to maintain temperature.  The second is that the Cool It Pure can't keep up with the load and we see the temperatures slowly climb out of control towards 90C.

After about 23 minutes of this abuse, Windows blue screens and the system is reset.  Bottom line here, while good for light overclocking, the Cool It Pure simply needs to cool it more; the Pure is just not enough for an enthusiast overclock.