Although the launch of Intel's seventh-generation processor series in January was a relatively uneventful affair, there were a few items of interest -- namely the unlocked Core i3 7350K, which captured most of Kaby Lake's headlines early on.
Despite that early intrigue, with a current retail price of $180, the 7350K is a mighty expensive dual-core processor and for $20 more you can land the quad-core Core i5-7400 (confusingly, both cost the same amount in Australia and other regions). Given their similar prices, quite a few of you have asked which is the better buy between the Core i3-7350K and Core i5-7400.
The advantage of the slightly pricier Core i5-7400 is that it has four cores and larger L3 cache while its disadvantage is that it's locked at a base clock frequency of 3GHz with a maximum single core operating frequency of 3.5GHz. There is a bit more to this comparison but that's the gist of it.
The Core i3-7350K on the other hand comes clocked at least 20% higher, 40% higher in fact when compared to the i5's base clock frequency. This is also an unlocked-K processor which means it can be overclocked to achieve even greater frequencies. I got my chip up to 4.8GHz without much fuss and that's almost 40% above the i5's maximum turbo boost frequency.
A clock speed advantage of roughly 40 to 60% is huge and with its support for Hyper-Threading the 7350K should really challenge the 7400. There are however a few other factors at play here which make the 7350K look a whole lot less enticing, so let's touch on that before we even get to the benchmarks.
Consumers can pretty much get the most out of the Core i5-7400 on a $50 H110 motherboard with the standard Intel box cooler, while the 7350K requires a Z-series motherboard. Z170 boards start at $90 and Z270-based models start at $110, which is quite a bit more than an H110 motherboard. Not only, that but the 7350K will require an aftermarket cooler so you can add another $30 to the price.
Therefore, you're looking at $250 for the Core i5-7400 with an entry-level motherboard whereas the 7350K will set you back at least $300 with a basic Z170 board and budget tower style air-cooler. So in the end you are paying about 20% more for the 7350K and its required components. Keeping all that in mind, let's find out how the two compare...
Test System Specs
Kaby Lake System Specs
Vishera System Specs
Skylake System Specs
Sandy Bridge System Specs
Excel is an application that has no problem utilizing a large number of threads and as such the Core i5-7400 performs much better than the 7350K. Even overclocked the 7350K simply couldn't match the 7400, taking over 10% longer to complete the workload.
Surprisingly the overclocked 7350K was able to nudge ahead of the 7400 in the 7-Zip benchmark, that said it was just 4% faster.
For any kind of encoding work having four physical cores will always beat trump two cores with Hyper-Threading and we see that here when testing with Premiere Pro CC. Even at 4.8 GHz the 7350K was 4% slower than the 7100 taking 18 minutes and 16 seconds to complete the workload.
First up let's check out the single and multi-threaded performance using Cinebench R15. Here we see despite a massive clock speed advantage the 7350K is still quite a bit slower than the 7400 when comparing multi-threaded performance. That said, when overclocked the 7350K looks to be almost 40% faster for single threaded tasks.