You can overclock Core i5 processors from Ivy Bridge generations following one of the two different strategies. The first one is related to Core i5-3570K processors, which is designed as an overclocker model right from the start. This processor has an unlocked clock frequency multiplier and its frequency may be increased above the nominal value according to LGA 1155 specific algorithm: we increase the CPU clock frequency by raising the multiplier and at the same time improve CPU cooling and increase the CPU Vcore accordingly to achieve stability.
Without any Vcore adjustments our test Core i5-3570K overclocked to 4.4 GHz. To ensure stability in this mode we only had to switch the mainboard Load-Line Calibration to High.
By pushing the CPU core voltage to 1.25 V we achieved stability at higher 4.6 GHz clock frequency.
This is a pretty common result for Ivy Bridge processors. These CPUs overclock a little bit less than those from Sandy Bridge generation. Supposedly, it is caused by the smaller semiconductor die as a result of the migration to finer 22 nm process, which required increased heat flow density during overclocking. At the same time the internal thermal interface used by Intel inside their CPUs, just as the regular means of dissipating heat from the surface of the CPU packaging, didn’t really help much.
However, 4.6 GHz is still a very good result, especially keeping in mind that Ivy Bridge processors are about 10% faster due to their microarchitectural improvements compared with Sandy Bridge CPUs working at identical clock frequencies.
The second overclocking algorithm should be applied to all other Core i5 processors, which do not have an unlocked clock frequency multiplier. Although LGA 1155 platform doesn’t handle the increase in the base clock generator frequency too well and often loses stability at even 5% frequency increase, it is still possible to overclock non-K Core i5 processors. The thing is that Intel allows slightly increasing their multiplier by setting it no more than 4 points above the nominal value.
Keeping in mind that in this case Turbo Boost technology remains fully operational and allows overclocking Core i5 Ivy Bridge processors by 200 MHz even when all processor cores are utilized, the overall clock frequency “boost” can add up to as much as 600 MHz. In other words, Core i5-3570 may be overclocked to 4.0 GHz, Core i5-3550 – to 3.9 GHz, Core i5-3470 – to 3.8 GHz, and Core i5-3450 – to 3.7 GHz. And this is exactly what we saw during our overclocking experiments:
I have to say that the non-overclocker processors are even easier to overclock than the Core i5-3570K. Relatively low increase in the CPU clock speed doesn’t cause any stability issues even with the nominal Vcore settings. Therefore, the only thing you will most likely need to do during non-K Core i5 Ivy Bridge processors overclocking is to change the multiplier in the mainboard BIOS. Although the obtained result won’t be a record-breaker, it will most likely be more than satisfying for the majority of non-extreme users.