The additional 100MHz core speed, 2MB Level 3 cache and hyper-threading proved to be of a fair advantage for the Core i7-3770K over the Core i5-3570K in several of our tests. At stock speeds the Core i5-3570K scored 3,160 in the video encoding test - 301 points or roughly 10 per cent short of the Core i7-3770K. It was noticeably slower in Cinebench R11.5 and WPrime 2.05 too - in percentage terms it was over 20 per cent slower in Cinebench but these results are to be expected given the difference in features outlined above and the fact the Core i5-3570K is around £80 cheaper.
Where hyper-threading was able to make less of a mark, the Core i5-3570K was only slower by the slightest of margins - a paltry 54 points in the image editing test and 46 points adrift in the multi-tasking test for example. The difference was even smaller in our game tests with barely single frames between the two CPUs at stock speeds.
The question most people want to know, of course, is how much faster is it than the Core i5-2500K? The answer is a noticeable but not jaw-dropping amount, usually around 10 per cent, although this was consistent in all of our benchmarks. The Core i5-3570K had a 6fps advantage in Arma II: Operation Arrowhead - a 7 per cent advantage, with older Sandy Bridge CPU being 147 points adrift in the image editing test - again roughly the same in percentage terms.
Low power consumption is one of the most trumpeted features of Ivy Bridge and the Core i7-3570K proved to have clear advantages over its predecessor. At idle, the Core i7-3570K system drew 97W from the wall compared to 114W for the Core i5-2500K - not bad considering the former is roughly 10 per cent faster, has a beefier IGP and 100MHz clock speed advantage. Under load, the difference was only 1W though.
The concentration of heat with Ivy Bridge CPUs is proving to be a tricky obstacle to overcome. Air cooling yields much the same results as it did with Sandy Bridge 'K' Series CPUs with 4.6GHz usually an easy target. Using a multiplier of 50x, baseclock of 100MHz and a vcore of 1.4V, we pushed our Core i5-3570K to 5GHz with Extreme Load Line Calibration enabled and C-states disabled too.
However, while our Corsair H100 didn't feel particularly warm, the temperature of our CPU was sky-high and only just below the Tj Max of 105°C. It's clear that the heat density is so high, that modern coolers are simply focussing their efforts on too large an area. High-end water cooling may help to deal with anything significantly higher than 4.8GHz, but this is still a stonking overclock that easily achievable with a high-quality air cooler.
At 5GHz, the Core i5-3570K posted the fastest image editing score in the graphs, bettering the likes of the Core i7-3960X Extreme Edition by quite some margin. Interestingly, the boost was enough to better the Core i7-2600K in our video encoding test too - not bad considering the two CPUs were both clocked at 5GHz, yet the older CPU was equipped with hyper-threading. Arma II: Operation Arrowhead saw a hefty boost in frame rates over the stock speed numbers but the increase in Shogun 2: Total War CPU Test was nothing short of spectacular, with the Core i5-3570K coming top by a noticeable margin, clearly due to its higher clock speed over the Core i7-3770K .
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Despite the higher-than-expected cost and higher operating temperatures, the Core i5-3570K is a worthy successor to the Core i5-2500K. It's noticeably faster, more power efficient, has a more powerful IGP and combined with a Z77 chipset motherboard, will offer far more features too. However, as with the Core i7-3770K, the upgrade from a 'K' series Sandy Bridge CPU represents poor value - the Core i5-3570K just isn't that much faster.
It's certainly much less of a performance jump than it was from Clarkdale to Sandy Bridge; here the upgrade from a Core i5-760 to a Core i5-2500K was definitely worth it. There are notable exceptions: Shogun 2: Total War saw huge improvements going from Sandy Bridge to Ivy Bridge, at stock and overclocked settings. This aside, though, while the Core i5-3570K is undoubtedly the new mid-range performance king, it's not a logical upgrade if you currently own a Core i5-2500K. As such it missed out on a Premium award. Whether that's disappointing will probably depend on your situation but if you need a new quad-core CPU now, and you're not fussed about hyper-threading, this is still the one to get.