Is it time to upgrade from Core i7-3770K Ivy Bridge or from Sandy Bridge?  What about upgrading from the i7-4770K to Intel’s latest Devil’s Canyon CPU – the i7 4790K – in the pursuit of a few more good MHz?

This evaluation has been a long time in the making, and it has taken us a full month to run all the benchmarks with our updated 33-game benchmark suite.  We received a Core i7-4790K as an upgrade from Intel for our Core i7-4770K which we originally could stably only overclock to 4.2GHz in our Z87 ECS flagship “Golden” motherboard.  Since i7-4790K is a drop-in upgrade for the ECS flagship motherboard, we will compare our i7-4770K and i7-4790K – stock and overclocked – in this motherboard, as well as in Intel’s latest Z97 platform using a new ASUS Z97-E motherboard that we purchased from Newegg on Black Friday for $100.

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We shall also see if the newest Haswell Z97 platform can allow our i7-4790K to top the performance of 4770K in our Z87 motherboard at 4.2GHz, as well as Ivy Bridge’s Core i7 3770K at 4.6GHz using the EVGA Z77 FTW motherboard.  Compared with our benchmarks in the past, we have a much faster video card, the GTX 980, which is able to differentiate between CPU speeds at 1920×1080 and at 2560×1600 resolutions.  We also use GTX 980 SLI to test SLI scaling with our stock and overclocked CPUs in our three test motherboards.

In this evaluation we shall use 2x8GB of Kingston’s Hyper-X Beast RAM at its XMP Profile 1 speed of 2133MHz.  We want to see if it is worth it for a gamer to upgrade his CPU platform for Devil’s Canyon, and we will test 33 games, including our 8 newest games which have been added since October.  And we shall also benchmark using 3 synthetic gaming tests to determine the progress that Intel has made with their latest Haswell CPU in performance, as well as giving a quick nod to CPU temperatures and overclocking.

msata-m2Since the Z97 chipset is an incremental upgrade over Z87, we will focus on fast graphics.  The Z97 chipset’s only notable improvements include future Broadwell support and slot M2 support which is a potentially much faster upgrade for the mSATA connector commonly used in the Z87 chipset and even in the Z77 chipset.  Since we have two 128GB Kingston mSATA drives that we usually use for caching our 2TB hard disk drives, we purchased a mSATA to M2 adapter from Amazon.com for $16.75 which is pictured (from Amazon) to the left.  We did not use hybrid caching for this review.

Intel released the Ivy Bridge CPU architecture on 22nm in late April of 2013. We were able to briefly compare its performance in more than 20 games against our aging flagship 45nm Core i7-920 CPU at 4.2GHz by using a GTX 680 and GTX 690 on both platforms.  We are going to build on our earlier evaluations to carry out a Z87 to Z97 platform upgrade to compare our older ECS motherboard’s performance directly against the newest chipset in the ASUS Z97-E motherboard.

We shall also attempt to reach higher clockspeeds with our Core i7-4770K and will compare further overclocked performance above 4.2 GHz to test Haswell CPU scaling in gaming. We are continuing to help answer the question, if an overclocked Core i7-3770K at 4.5GHz (and perhaps Sandy Bridge CPUs also) should be upgraded when paired with the very fastest available video cards at the resolutions that gamers play at.  We shall also test at maximum details to determine if there are any significant framerate differences between our platforms at settings that gamers actually use.

Devil’s Canyon Core i7-4790K

The Ivy Bridge Core i7-3770K processor is offered in a 22nm 1155-land LGA package (H2) while Core i7-4770K and 4790K are also 22nm and are offered in a non-compatible 1150-land LGA package, which means you must upgrade your motherboard from Sandy or from Ivy Bridge to support a Haswell CPU.  Haswell is Intel’s “tock” which is new microarchitecture, whereas Ivy Bridge was Intel’s “tick” – a die shrink of Sandy Bridge’s 32nm architecture.

There are important differences between Haswell and Ivy Bridge CPUs, including an integrated voltage regulator in Haswell that was formerly part of the Ivy Bridge chipset.  Intel has focused on mobile which means lower temperatures and power savings for notebooks, but not so much on Haswell desktop performance by overclocking.

While there are some boosts to IPC (instructions-per-clock) and to performance, Haswell wasn’t designed for overclocking under high load.  Devil’s Canyon Core i7-4790K is the result of Intel’s effort to rectify the relatively weak overclocking of the 4770K, and improvements were made to the voltage regulators for extreme overclocks and to the thermal interface material (TIM).  We are interested to see if we can hit a higher overclock with our Core i7-4770K in the ASUS Z97 motherboard over the 4.2GHz that we settled for in the ECS Z87 motherboard as well as to see how far the i7-4790K can reach in both motherboards.

The ECS Golden Series Z87H3-A2X is ECS premium enthusiast Z87 motherboard that includes their “non-stop” technology and premium 99-hour replacement service.  We hit 4.6GHz with our i7-4770K but our overclock was not completely stable and the temperatures bordered on dangerous under load.

Even at 4.4GHz, the i7-4770K ran too hot for daily use.  4.2GHz was settled upon as its highest stable overclock, and we picked 4.0GHz for our regular benchmark runs which approximated the same performance of our i7-3770K at 4.5GHz.

mb-detailThe ASUS Z97-E is a no-frills basic Z97 motherboard that has the same overclocking capabilities of the more expensive ASUS boards.  Since it was offered for $100 at Newegg on Black Friday, we purchased it to test.  It is pictured above, image courtesy of the ASUS website.

The EVGA Z77 FTW motherboard is a somewhat finicky motherboard that was built for extreme overclocking.  We were able to hit 5.0GHz with our i7-3770K using a Cooler Master Seidon 240  water cooler, but the temperatures were much too high.  There is a very slight advantage to using SLI on this motherboard as it has a PLEX chip which supplies a bit more bandwidth than the regularly configured Z87 and Z97 8x+8xPCIe 3.0 chipsets.

In our testing even 4.8GHz was likewise too high for Ivy Bridge although repeatable “suicide” benchmarks could be run, and 4.6GHz was settled upon as the highest regular overclock which we also used in this evaluation.

 

Overclocking

Core i7 3770/4770/4790 “K” CPUs are multiplier unlocked and can usually easily be overclocked beyond 4GHz. On the other hand, the non-K CPUs are locked and cannot be overclocked in the traditional manner. Only the base clock may be overclocked which overclocks the entire system. Overclocks of 3-5+% with stability are reported and there can be a small performance boost. The Core i7-4770K and 4790K also have an unlocked base clock although we did not attempt to adjust it.

System RAM and Overclocking

When setting CPU overclocks it is recommended to move the RAM speeds to default, 1600MHz, or lower.  However, we found no stability difference either way and we kept our Kingston HyperX Beast DDR3 at its XMP Profile 1 default 2133MHz clocks for Haswell.  The FTW motherboard could only stably accept 1866MHz speeds as its top speed with the same Kingston RAM.

The Ivy Bridge 3770K Overclock versus Haswell’s 4770K (vs. Bloomfield, i7-920) versus Devil’s Canyon 4790K

The highest overclock we could manage with our Core i7-920 was 4.2GHz and it was accomplished stably with our Thermaltake Frio OC CPU cooler. To achieve the same 4.2GHz with Core i7-3770K we only needed .03V more added over default to stabilize our system. To reach 4.8GHz required an additional.13V and we needed our Noctua NH-DH14. If the reader is interested, they can check out the Noctua NH-DH14 evaluation to see how we reached our maximum overclock with Core i7-3770K, or the Frio OC evaluation to check out the i7-920 overclock.

In contrast, we were able to reach 4.2GHz and benchmark with our Core i7-4770K with stock voltage, but needed 1.300V to pass Linpack stress testing.   At 4.2GHz, temperatures peak in the upper 70s under maximum load, a few degrees over stock settings.  To reach 4.4GHz required 1.320V and temperatures peaked above 85C under Linpack’s load.  4.5GHz required 1.335V and Linpack peaked above 89C.  To benchmark games at 4.6GHz required 1.360V although our i7-4770K wasn’t stable under Linpak and temperatures climbed into the low 90s.  4.7GHz wasn’t possible with any voltage nor with tweaks suggested by ECS.  There wasn’t much difference with the ASUS motherboard and we settled on 4.4GHz as the top stable speed for the i7-4770K in this evaluation.

In contrast, the Devil’s Canyon i7-4790K overclocked, with no extra added voltage needed, to 4.6GHz in the ASUS Z97-E motherboard. Interestingly, it couldn’t overclock at all beyond stock in the ECS motherboard which turboed all its cores to 4.2GHz and potentially two of them to 4.4GHz when temperatures allowed it.  On the other hand, the ASUS Z97-E motherboard synced all 4 cores to 4.4GHz at its otherwise stock settings, so an extra 200MHz is not surprising.

Even at 4.6GHz, the i7-4790K in the ASUS Z97-E motherboard maxed out and remained in the middle to upper 80C under full Linpack load, and with complete stability using the Cooler Master Seidon 240 CPU water cooler.  Gaming temperatures were much lower.  We found that 4.7GHz was achievable but required extra voltage and the temperatures moved out of the 80sC and into the hot zone under full load.  We decided to stop at 4.6GHz and not bother with the extra voltage, heat, and noise the extra 100MHz would bring us.