Turning our attention to our shiny new Core i7-4770K, we started by cranking up the multiplier to see how far we got without touching any other settings. We eventually hit a wall at 4.4GHz with the PC throwing a BSOD at us at 4.5GHz as soon as we entered Windows. However it seemed perfectly stable at 4.4GHz, which is very similar to what you'd expect from an Ivy Bridge CPU.
From here, though, the temperatures increased rapidly and we reached our limit of 4.7GHz using 1.257V and a scorching temperature of 98°C, and that's using a Corsair H100i, which we know to offer the best cooling short of a custom water-cooling kit. The jury is out on why this might be - the 22nm manufacturing process is clearly going to add a lot of heat density, as we saw with Ivy Bridge, but like Ivy Bridge, there's the issue of thermal paste vs solder too. We're not about to take a razor blade to our only test sample just yet but reports from the community on this will likely surface soon as to whether de-lidding is on the cards again.
Two ways to get to 4.7GHz - baseclock overclocking (left) and multiplier overclocking (right) - ignore the voltage reading in CPUZ as it's inaccurate
Switching to baseclock overclocking and using the same voltage, we arrived at a similar result using the 1.25 strap, a 127MHz baseclock and multiplier of 37. Here the memory was running at 1,666MHz and we also had to knock the GT (GPU) and Ring ratios down a bit to keep the frequencies near their default values of 1,250MHz and 3,500MHz respectively - clearly a rather more complicated and time-consuming process than using the multiplier and we didn't see much difference in performance either.
We should add that while we achieved 4.7GHz, overclocking is never a guarantee. In fact other people we've spoken to have achieved far less so not only will heat prevent you running at 4.7GHz 24/7, you'll likely struggle to get there anyway from the odds we've heard, at least with early engineering test samples anyway.
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Stock speed results were pretty much as you'd expect with a modern new CPU from Intel. There's between four and 10 per cent increases pretty much across the board over the Core i7-3770K, with the most noteworthy win in the image editing test, where the Core i7-4770K held a significant point lead and is the first CPU we've tested to break the 2,000 point mark, a clear indication that the clock for clock performance has definitely improved. As per usual, the new Intel CPU was light years ahead of AMD's FX-8350, with its image editing score being more than twice as fast.
It held a similar lead in the video encoding test although the Intel Core i7-3960X Extreme Edition still rules the roost when it comes to multi-threaded performance. For some strange reason, our multi-tasking test returned somewhat inconsistent results, and the Core i7-4770K was some way behind the Core i7-3770K here, with everything bar the motherboard being identical. We've used the highest result we obtained and will report back if and when we find out what the issue was.
Overall, its score of 2,461 was still noticeably faster than the Core i7-3770K, although the monstrous video editing score of the Intel Core i7-3960X Extreme Edition helped it retain the lead by just 75 points. In games there were small but consistent improvements over previous generation CPUs too but if you're looking for a CPU to boost your gaming performance, Haswell probably isn't it.
Finally, the Cinebench score had the Core i7-4770K slightly ahead of the Core i7-3770K with a clear lead once we'd overclocked it. There were significant improvements across the board from overclocking, with a near 400 point increase in the overall media benchmark score and 6fps increase in the minimum frame rate in Shogun 2: Total war. Power consumption was slightly lower to the Core i7-3770K at idle,but slightly more under load and noticeably lower than all the other CPUs on test when overclocked at 142W, but then we we'd also had to apply the lowest voltage due to the CPU overheating.
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Intel clearly has things other than raw performance on its mind, as you've probably figured by the vast amount of efficiency and power saving-related marketing material preceding today's NDA. An average of a four to 10 per cent increase isn't to be sniffed at, though, but it does mean that the Core i7-4770K, and most likely the Core i5-4670K too, isn't a particularly worthwhile upgrade for those with equivalent Sandy Bridge or Ivy Bridge CPUs.
There are some substantial improvements, particularly in our image editing test over the Core i7-2600K, for example, but the 15 per cent performance lead here is a rare one. For new system builds, however, the choice is clear - there's no point buying an Ivy Bridge system given your upgrade path is about as long as a day in an arctic winter and equivalent Ivy Bridge CPUs cost practically the same and don't offer a lot more by way of overclocking either.
Haswell is a definite and sometimes significant improvement over Sandy Bridge and Ivy Bridge. Somehow the PC enthusiast and overclocker in us hoped for more, though, and it seems we'll once again be hampered by temperature when it comes to overclocking. However, we can't dispute the numbers. If you're after a new system and need a fast hyper-threaded CPU, this is the one to get.