Intel Core i7-5775C review: The unwanted desktop Broadwell has one neat trick

This chip arrived already obsolete, but benchmarks comparing it to Haswell and AMD Godavari show its true colors.

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How we tested

For my test, I used an Asus Z97-Deluxe motherboard with 16GB of DDR3/1600 and 240GB SSD. I updated the motherboard to the latest UEFI available, installed a fresh copy of 64-bit Windows 8 and hunted down the latest drivers as well. Because the graphics capability of the the Broadwell C is a driving feature, I tested it without a discrete GPU.

I realize that decision doesn’t track with what most people are doing with these expensive CPUs. I’d bet it’s close to 90 percent who pair higher-end CPUs with graphics cards for gaming. Still, the graphics performance of these chips is a very important feature.

Broadwell C Gordon Mah Ung

Broadwell is technically a “low power” chip with a TDP of 65 watts.

The competitor was a natural choice: Intel’s Core i7-4790K, aka Devil’s Canyon. 

The Core i7-4790K has a clock speed of 4GHz and will Turbo Boost up to 4.4GHz on some loads. It has Intel HD4600 graphics and on the street sells for $340. For more details, I’ve lined both them up at Intel’s ARK website. It’s pretty much the pinnacle of quad-core Haswell performance.

Besides the Broadwell to Haswell generation difference, the other factor that matters here is the clock speeds between the two chips. The Broadwell Core i7-5775C has a base clock of 3.3GHz with a Turbo Boost of 3.7GHz. 

Encoding

The first test we can discuss is our Handbrake workload. We use the free and popular Handbrake encoder to convert a massive 30GB MKV file into a much more compact MP4 file using the Android Tablet preset.

Notes: Our normal system review benchmark uses the 0.9.9 version but for this, I wanted to use the latest version of Handbrake 0.10.2. Because it does effect the encoding time, you can’t compare results between the versions. Handbrake allows you to choose different encoders so for the first one, I used x264, which is heavily multi-threaded and keeps the workload to the x86 cores in the CPU.

The result was a big win for the Core i7-4790K and clock speed in general. 

corei7 5775c handbrake 10 x264

Handbrake when confined to the x86 cores in the CPUs favors the higher-clocked Haswell chip over Broadwell.

But wait, encoding video isn’t done just on the x86 side anymore. Today, encoding on the GPU is the way to go for performance, and Intel has dedicated transistors for hardware encoding into its chips, called Quick Sync. What happens when we give Handbrake the same task, but using the graphics cores instead?

corei7 5775c handbrake 10 quicksync

As Madden says: Boom. Quick Sync on the Broadwell C stomps the higher-clocked Haswell CPU.

Boom: The improved Broadwell graphics cores combined with its massive eDRAM flips this battle on its back. Besides whistling at how much of a recovery the Core i7-5775C made here, you should also take note of the encoding time it took using the GPU cores rather than the x86 cores in the CPUs. The Core i7-5775C, for instance, takes a third of the time to get the work done. There are arguments that GPU encoding leads to visual impurities, but when you’re crunching a file down to watch on your phone, who cares?

3D rendering

Next up, we used Cinebench R15, a test based on Maxon’s Cinema 4D animation package. It’s a great benchmark that is pure CPU and heavily multi-threaded. The result is no surprise, as 3.7GHz even with the newer Broadwell cores can’t beat 4.4GHz. 

corei7 5775c cinebenchr15 all cores

Clock speed wins. Again.

Work performance

Our next test is PCMark 8, which simulates various computing tasks broken down into Work, Home and Creative categories. Work measures general Office Drone tasks, Creative throws in photo, video and light gaming, while Home factors in more casual gaming. 

The first result is from PCMark 8 Work Conventional. Again, the Core i7-5775C's lack of clock speed shows even on these basic tasks that a Celeron could run.

corei7 5775c pcmark work conventional

PCMark 8 Work Conventional measures simulated Office Drone performance.

Creative performance

Once PCMark 8 mixes gaming performance into this test, the Broadwell makes a nice comeback. The result is similar in the PCMark 8 Home test, which adds gaming into the mix and puts the Broadwell in a much better light than the Haswell, thanks to its better gaming capability.

corei7 5775c pcmark creative conventional

PCMark 8 Creative Convetional throws video and photo editing into the test load.

Chess performance

The Fritz 12 Chessbenchmark measures a CPU’s ability to calculate chess moves. The yard stick is a 1GHz Pentium III. A score of 10 would mean the tested CPU is 10 times faster than a 1GHz Pentium III performing the same tasks. The results again don’t look great for the Broadwell desktop part. Even though we know Broadwell’s cores are maybe 5 percent more efficient doing the same task, it’s not enough to compensate for the higher clock speeds of the Core i7-4790K chip.

corei7 5775c fritzchessbenchmark

The Fritz chess benchmark measures how fast a CPU is at calculating chess moves. Each of those “units” is the performance of a 1GHz Pentium III.

Overall meh right? 

If you’re thinking 'stick a fork in Broadwell, and call it a day,' you need to read on to see where the Core i7-5775C is better than Haswell.

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