Overclocking Core i7-3770K: Learning To Live With Compromise

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We recently took our first look at Intel's Ivy Bridge architecture. Then, we evaluated its efficiency. Now, we turn to overclocking. Recently, each of Intel's die shrinks has helped increase frequency headroom. This time, however, we ran into some walls.

Ivy Bridge Takes A Bronze In Overclocking; Gold In Efficiency

We're not going to mince words here. The new Ivy Bridge-based processors manufactured at 22 nm serve up high performance and moderate power consumption. They can be overclocked to respectable levels. With that said, though, Intel's preceding generations helped facilitate impressive overclocking, and our expectations for this generation were higher. The first retail CPUs employing the Ivy Bridge architecture cannot be overclocked as well as their predecessors on conventional air cooling. However, the difference in attainable clock rate translates to similar performance when you compare to the fastest Sandy Bridge-based chips.

In Practice There Are Clear Frequency Limits

The small die size of Ivy Bridge turns into a mixed blessing. Packing four cores, a more complex GPU, and 8 MB L3 cache into a mere 160 mm2, the new chip occupies 26% less area than a comparable Sandy Bridge CPU. Disregarding the GPU, which is bigger now than, the CPU shrinks by approximately 40%.

Intel counters the smaller die by dropping Ivy Bridge's thermal ceiling. Overclocked, though, Ivy Bridge must dissipate close to the same heat as a Sandy Bridge-based CPU, but across less surface area. It is pretty clear that Intel's decision to use thermal paste instead of thermally-conductive solder puts a vice on the frequencies this CPU can stably achieve. The end result is a more pronounced and rapid thermal ramp-up that can only be effectively addressed using more aggressive cooling solutions. In a nutshell, for an average system builder, there are clear limits to overclocking Ivy Bridge. We will have to wait and see if future products from Intel employ better material between the processor die and heat spreader.

Clear Real-World Advantages

With all things considered, despite its limited overclocking potential, Core i7-3770K is only slightly slower than the 32 nm Core i7-2600K with both CPUs pushed as far as they can go. In practice, the difference isn't noticeably, though.

At idle and under load, though, the Ivy Bridge-based chip draws significantly less power. Power users satisfied with frequencies under 4.5 GHz can get great performance with low power use from a Core i7-3770K. But the recommendation we made in our launch story stands: this isn't worth an upgrade if you followed our advice last year and bought a fast Sandy Bridge-based chip. Really, it's only the right move for folks stuck on platforms more than a generation old.

Patrick Schmid