Operational and Overclocking Specifics
We had absolutely no problems or even difficulties assembling our testbed configuration around the ASUS P8Z77-V Deluxe mainboard. As we’ve noted above, its classic design is very user-friendly. Started up, the mainboard shows an unremarkable picture that fails to remind you about any hotkeys other than Del.
There is no real reason to turn the startup picture off, though. The mainboard still does not tell you anything about hotkeys. The memory frequency is the only useful information because the default rather than actual clock rate is reported for the CPU. ASUS’s Republic of Gamers mainboards have long been able to correctly report the actual CPU clock rate but the company hasn’t added this capability to its ordinary products as yet.
Again, we had no problems installing the OS and running the mainboard at its default settings. It is at overclocking that we encountered some difficulties. First of all, we have to admit that our earlier apprehensions about low overclocking potential of the new Ivy Bridge CPUs seem to be confirmed. We had started our tests using an engineering sample of Core i7-3770K and overclocked it easily to 4.7 GHz, but now that there are serial Ivy Bridge processors available, we guess we should use them in our testbed. The first sample of Intel Core i5-3570K was a little disappointing. It had a lower default voltage. Without increasing the voltage, it could be clocked at 4.3 GHz instead of the previous CPU’s 4.4 GHz. And when its voltage was increased, it could be clocked at 4.6 GHz. That’s not a bad result, but this CPU, despite its lower voltage, had a higher temperature than the engineering sample of Core i7-3770K. The second sample of Core i5-3570K we took next was blameless, though. It could be clocked at 4.4 GHz with its default voltage and at 4.7 GHz with increased voltage, so we are going to use this sample for our mainboard tests.
We found out one peculiarity about all of these CPUs, though. When overclocked, they could successfully pass through hard stability tests with LinX and Prime95 but then produced errors or BSODs in an ordinary application or game. At first we thought there was something wrong with the P8Z77-V Deluxe but later had the same problems with mainboards from other makers.
As a matter of fact, overclocking an Ivy Bridge is the same as overclocking any other CPU. You increase its clock rate, increase its voltage and check out its stability at such settings. You just need to run as many stability tests as possible because one or two stress tests may not be enough. After a substantial increase in voltage, our CPU was stable at a clock rate of 4.7 GHz.
We also want to remind you about the difficulties of cooling Ivy Bridge CPUs. While running LinX, our CPU overclocked to 4.7 GHz would get as hot as 97-98°C, occasionally reaching 100°C when it was hot in our lab. This overclocking is hardly safe considering that the frequency throttling of the new CPUs is triggered on at 105°C. We used an open testbed, so if the mainboard with CPU were put into a system case and if the room temperature were higher, the thermal throttling would enable protective mechanisms and the overclocked system would perform slower rather than faster. Therefore we had to limit ourselves to 4.6 GHz. The memory was overclocked to 1867 MHz.
We always overclock mainboards in such a way that they could be used permanently in such mode. Therefore we do not disable any features, e.g. onboard controllers, and try to keep the CPU’s power-saving features up and running. The P8Z77-V Deluxe was overclocked in this manner, too. When idle, it lowered the CPU's voltage and frequency multiplier to save power.