Review: Intel Core i5-4670K (22nm Haswell)

The second-rung K-series chip

Got your heart set on building a new PC for gaming? Good, because both Intel and AMD have upgraded their CPU technology in the last two weeks.

Intel's shift from third-generation to fourth-generation Core processors is arguably the bigger move, with the Haswell chips requiring new motherboards - LGA1150 vs. LGA1155 - and offering numerous power-saving benefits over Ivy Bridge. Our in-depth review found that Haswell plays best in laptops and Ultrabooks, which is precisely how Intel wants it, yet the concurrent release of desktop processors means the gamer isn't forgotten.

Haswell is more than just 4770K

All told, Intel has brought a dozen new fourth-gen Core chips to market, headlined by the £260 Core i7-4770K. Look further down the stack and the Core i5 processors - those without hypertheading support - tend to offer the better bang-for-buck.

Just as the Intel Sandy Bridge era was lit up by the Core i5-2500K and the Ivy Bridge days with a Core i5-3570K, Intel is continuing the theme with the Core i5-4670K for Haswell. Note how each generation is accompanied by model-number inflation? So where does this mid-range chip stand in relation to other fourth-gen processors? Well, just take a look at the following table.

Keeping family values intact

The relationship between the 4670K and 4770K is almost a mirror image of that present for 3570K vs. 3770K. The two sets of equivalent processors operate at the same speed and Turbo Boost to identical frequencies, while last-level cache is also kept constant between generations. The minor model-to-model disparity rests with the maximum speed of the IGP, as the 4770K runs marginally faster than 4670K - the 3770K and 3570K, meanwhile, are both specified to 1,150MHz.

Intel has raised the price of desktop chips for Haswell, because the equivalent 3570K model was $30 (£20-£25) cheaper than the 4670K. Putting this into a UK context, we saw the Ivy Bridge chip first surface at £160 while the Haswell equivalent is now £190. The non-K version, which is multiplier-locked upwards, is available for £170, however, and those with penchant for running quiet computers would do well to take a close look at the 4670T and 4670S chips.

No TSX or vT

It is entirely reasonable to expect the K-series processors to be the pinnacle of a certain family but this is not entirely the case. Delving deeper into the specification reveals that K-class chips miss out on the transactional synchronisational extensions (TSX) and virtualisation support (vT). Not having TSX could be construed as a big deal in the future. TSX can potentially improve multi-core efficiency by letting the CPU decide how best to 'lock' a thread so that it isn't worked on until processor resources are fully ready for it. Software-based thread-locking, which is the status quo, can be inefficient and, playing it safe from a programmer's point of view, rather coarse in implementation, leading to wasted CPU resources. Note, however, that this move from software to hardware locking requires software that's written with TSX in mind.

Future performance efficiencies aside, the enthusiast, whose focus tends to be on the K-series processors, really wants to know what extra they receive from the change between Ivy Bridge and Haswell, we'd imagine. The specifications and analysis suggests a fundamentally better integrated graphics processor (hardly inspiring for the dyed-in-the-wool gamer) along with minor improvements to CPU-side processing.

There's an easy method of substantiating or refuting Intel's claims that the fourth-generation chips are the best yet. That process is know as the HEXUS Benchmark Wringer™, so let's get straight to it.