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Question: I currently have a i5 2500k oc at 4.2 GHz.  Would I see much of a performance increase upgrading to a CPU like this one?
Document: I waffled between purchasing this vs the i5 but ultimately decided on this CPU. I'm doing more and more content creation (Adobe Premiere PRO, audio editing, etc.) and I have to say that I'm glad I stepped up to purchase the i7. I'm currently sitting at a 4.7 GHzOverclock with stable performance and decent temps at load. 4.8 GHz was achievable but not stable enough for my taste.
I'm not sure about the other reviewers, but mine runs cool and fast! I could only achieve 4.2 on an air cooler and it stayed under 70c while benchmarking in a full load environment.I've bought 2 previous i5 systems and this one tops them all.This replaced a i5-2500k that I used to overclock to 4ghz on a z68 board. Even at stock speeds this CPU is a noticeable upgrade.Maybe the other users are receiving high temps because of bad thermal paste management?
Several weeks ago I installed an i5 4670 that would overclock at about 4.2 which was marginal so I throttled it back  to 4.0 Ghz. Decided I needed multi-threading capability having multiple applications/websites opened simultaneously. Installed the i7 4770 and have overclocked at 4.3Ghz with absolutely no issues with stability of heat. The EVO Cooler Master 212 along with the Cooler Master JetFlo pressurizing the case are marvelous.
I prefer to build my gaming PCs to last at least 3, hopefully 5, years. This CPU is the only one out there currently that I believe will last for the next 5 years. The i5-4670K is an acceptable alternative, but this is the best. I replaced the stock cooler with an ARCTIC Freezer 7 Pro Rev. 2, CPU Cooler - Intel & AMD, Multi-Directional Mount, 92mm PWM Fan which works whisper quiet and I highly recommend.
I can safely say that it's not worth upgrading if you have an Ivy Bridge CPU (3570K, 3770K). My previous CPU was the 3770K and I had it overclocked to 4.8Ghz using only 1.38 volts with an H100i from Corsair. I delidded my 3770K and now my temps never go above 80c. Now that I have the 4770K, overclocked to the same frequency, the difference is ~2-3% faster in pretty much everything that I have tested, from games to applications.
Very solid processor.As this is a new socket change, upgrading from Ivy Bridge to Haswell isn't really worth it.Not a huge performance increase over Ivy Bridge, and you would have to buy a new motherboard to support the new platform.Typically new platform launches show decent performance changes.
It will give you dramatic performance increases in every aspect of the use of the computer. I can't speak for the other intel platforms that came after bloomfield.If you don't do heavy number crunching work that really benefits from the multi-threading capabilities of the i7, the i5 4670k should dish out 95% of the performance capabilities in other tasks (like gaming, etc).I rank the 4770k @ 4 stars. I subtract 1 star because it's a much steeper price of entry vs the aforementioned 4670k.
So I bought this CPU to replace my aging Phenom II 955, and I didn't expect much, but was greatly surprised. I coupled this processor with an Asus Z87 Pro, and it blows away the AMD. Yes the AMD is almost 3 generations old, but many people still see it as a viable contender. I used to be one of those people, until now. I play mostly Arma 2 & 3, and they are both CPU intensive games.
Its a very good CPU. Intel should have make it more overclockable. It went to 4.2 Ghz at 1.21V on Air cooling. Very good CPU but after 4 generations I think an I7 should have 6 to 8 cores and more overclockability. My old i7 920 Nehalem went from 2.66 to 3.8 on air without issues, so I had more frequency range. This one goes from a 3.7 turbo to 4.2 nice but not getting 5 stars.
I am very happy with this CPU. Having it run 4.9ghz without a problem on a ASUS Rog Maximus VI (6) Hero Mobo and 24gb RAM @ 1600mhz.Runs Shaders smooth. Used a Core i5-??? which went out after a Un-stable OC @ 4.5Ghz on a H60 Water loop.The CPU runs cool @ 40c idle75c Load with a water loop cooler with a double 120 fan radiator.Would recommend.Cheap for the performance!
Answer: Yeah, actually it would be a pretty drastic improvement, considering the 4770k has the highest single core cpu performance and if you have a decent cooling system you can get some serious results.