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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The narrative is already in place on Intel’s new Broadwell for desktop CPU: It’s the chip no one wanted.

As someone who watched this story unfold, I know the truth is actually the opposite. You see, Intel’s 3.3GHz Core i7-5775C is actually something the Internet demanded.

Remember that in 2012, the Internet said Intel would effectively “kill the desktop” PC because the company had no plans for a socketed CPU past Haswell.

Broadwell C Gordon Mah Ung

Intel’s Broadwell flanked by a Haswell, Sandy Bridge, and massive Haswell-E chip.

The truth is, Broadwell was always intended as a lower-power part with no practical appeal outside of laptops, NUC-style computers and all-in-one PCs. Instead, Intel told me at the time, desktop sockets will get a workout with the next big thing: Skylake.

Anger and hand-wringing ensued. Soon, bowing to pressure from its die-hard desktop community and PC vendors, Intel rolled over and decided to make a socketed version of Broadwell.

That brings us to the new Core i7-5775C—the CPU Intel never wanted. Now it looks like not even the crowd that demanded the chip will want it. 

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Here’s Intel’s new Broadwell quad-core team. The HQ denotes mobile CPUs, the R chips will go into all-in-one, and the C chips are socketed.

What Broadwell is

Intel announced 10 Broadwell CPUs in June at Computex. Half will go into laptops, and another three will be soldered on motherboards in all-in-one or Mini PCs, as Intel originally planned. But of those 10, two will fit into the traditional socket that desktop users want. That’s what I’m looking at today.

The Core i7-5775C will work in most 9-series motherboards and systems out there with BIOS support. Just be advised, that’s not exactly straightforward. To get my Core i7-5775C up and running, I didn’t just have to update the BIOS; I had to update it the right way. Check with your motherboard maker if you plan to go with a Broadwell C part.

Broadwell is a 14nm-process CPU that should offer a 5-percent or so performance increase over Intel’s 4th-generation Haswell CPUs, if all things were even. My own tests of Haswell vs. Broadwell mobile parts confirmed that. 

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Although this chip isn’t a socketed version, it gives you an idea of what Broadwell C looks like. The chip in the center is the CPU while the chip on the right is the 128MB of eDRAM cache.

Everything isn’t even, though. The pair of Broadwell C chips Intel has produced feature a massive 128MB of Level 4 (L4) cache using embedded DRAM. This cache is slower than the cache integrated into the CPU itself ,but because it’s actually a chip sitting next to the CPU and wired directly to it, it’s a magnitude faster than using system RAM.

This isn’t a new trick. Intel actually sold three Haswell CPUs with a similar 128MB L4 cache aboard. Those CPUs were available only in NUC-style machines like the Gigabyte Brix Pro and soldered down to the motherboard. Like the Broadwell desktop chip, the eDRAM’s existence is mostly to address graphics performance, where memory bandwidth is king.

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