Intel Core i5-2500K review

Intel’s Sandy Bridge codenamed processors are finally with us. We’re not impressed by the company’s unadventurous naming strategy, keeping the Core i7, i5 and i3 brands, and the introduction of yet another socket is also a pain – and means you can’t upgrade to the new chips on your existing motherboard.

On the positive side, the new Core i5 range (of which the 2500K is the top model) is now more consistent. Previous i5 processors could have two or four cores, with some having built-in graphics, and some not – a very confusing situation for those trying to build a new PC. All the new Core i5s are all quad-core processors and have built-in graphics chips – so at least you know what you’re getting.

The i5 range lacks the Hyper-Threading seen on the new i7 processors, and so it can’t simultaneously queue and execute two instructions. All new Core i5s have 6MB of L3 cache, compared to 8MB in the Core i7s, and the graphics cores run slower too, at 1100MHz rather than 1,350MHz. You still get all the benefits of the new graphics chip, including HDMI 1.4a, see our Core i7-2600K review for full details.

The Core i5-2600K has a base frequency of 3.3GHz, though the chip rarely ever runs at that speed. It Turbo Boosts up to 3.7GHz under load, and clocks down to 1.6GHz when idling to save power. In our benchmarks it was incredibly quick across all the tests. It scored 173 in image editing, 186 in video encoding and 158 in multi-tasking, with an overall score of 174. This is all compared to a score of 100 from a quad-core AMD Phenom II running at 2.8GHz.

All the new i5 processors can have their multipliers overclocked by up to four steps, or 400MHz, and the K-designated processors are completely unlocked and can be pushed far faster if desired.

We pushed up the maximum multiplier on our chip by four steps for a top speed of 4.1GHz. This is a maximum target remember, and so in our multi-threaded video encoding test, we saw it throttle back to around 3.8GHz to keep it from overheating. Not surprising, as we were only using the standard low-rise Intel cooler for this test. Still, the overclock resulted in an incredible overall score of 191.With a larger tower-style cooler we saw it stick to the maximum multiplier setting far more consistently, with a score just shy of 200.

Even factoring the cost of a new motherboard, the latest Core i5 is a great buy. It’s an incredibly fast processor, and for those still using older Core 2 Duo or Quad chips, it’s a great motivation to make the upgrade. We’d recommend getting the 2500K version, as for only a few extra pounds you get an unlocked chip to experiment with, and so it wins our Best Buy award.