Review: Intel’s Broadwell mini PC is a next-generation Ultrabook in a box

CPU performance: Broadwell U is a mild bump

Broadwell is a "tick" on Intel's roadmap, which means it takes its predecessor's CPU architecture (Haswell) and moves it to a new manufacturing process (14nm). This arrangement helps to minimize the likelihood of manufacturing problems with new chips, though as we've seen with Broadwell's delayed and protracted rollout, this strategy isn't always 100 percent effective.

At any rate, "tick" years generally aren't big ones for performance. A new manufacturing process gives Intel the ability to reduce power consumption, increase performance, or both, and the new NUC gives us a look at what kind of balance Broadwell strikes.

Here are the CPUs and GPUs we're comparing in the charts below. All systems include 8GB of 1600MHz DDR3 RAM.

• The Broadwell NUC, which has a Core i5-5250U CPU and an Intel HD 6000 GPU.
• The Haswell NUC, which has a Core i5-4250U CPU and an Intel HD 5000 GPU.
• The Ivy Bridge NUC, which has a Core i3-3217U CPU and an Intel HD 4000 GPU.
• The 2015 Dell XPS 13, which has a Core i5-5200U CPU and an Intel HD 5500 GPU.
• The 2013 Dell XPS 13, which has a Core i3-4210U CPU and an Intel HD 4400 GPU.
• The Gigabyte Brix Pro, which has a quad-core Core i7-4770R and an Intel Iris Pro 5200 GPU.

Comparing the Broadwell i5-5250 to the Haswell i5-4250 is about as apples-to-apples as you can get. A higher clockspeed and architectural improvements help the new CPU beat its older counterpart by around 10 percent. Not an amazing leap forward after a year and a half wait, but not entirely unexpected given Broadwell's “tick” status.

This may not be true for thin-and-light laptops with less room to dissipate heat, but despite having a "base" clock speed of 1.6GHz, the i5-5250 in the NUC can sustain a Turbo Boost clock speed around 2.4GHz indefinitely. We ran the Prime95 CPU torture test for more than 20 minutes, and the clock speed hung out somewhere between 2.37 and 2.45GHz for the entire time. Even the Haswell NUC would ramp down to about 2.0GHz under the same kind of sustained load.

It's definitely something to consider if you're comparing the i5 NUC to older i5 NUCs, or to versions without Turbo Boost—the base clock speeds don't tell you everything you need to know.

GPU performance: A bigger jump, plus improved 4K support

Given the smallish CPU performance improvements, we were hoping for more drastic generation-to-generation performance gains on the graphics side. Intel has been prioritizing GPU improvements over CPU performance for the last few years, mostly because there was a gigantic performance chasm to close between its 2010-era GPUs and even the lowest-end dedicated graphics cards.

The i5-5250U includes the Intel HD 6000 integrated GPU, which is the third-fastest option in the lineup. The Iris Pro 6100 is the same GPU with a higher clockspeed and larger thermal envelope, and there's an as-yet-unreleased Iris Pro 6200 GPU coming with future Broadwell chips that will add integrated eDRAM to boost memory bandwidth (Intel hasn't announced it officially and we don't have final specs for it, but it's mentioned by name on this support page for Intel GPUs).

We've compared the HD 6000 to a bunch of different integrated GPUs here, but the ones to pay the most attention to are the HD 5000 (the equivalent Haswell GPU) and the HD 5500 (the next-lowest Broadwell GPU, and the one most PC OEMs will end up using in Ultrabooks).

Here, Broadwell is definitely a better performer than Haswell. In most of our benchmarks, the HD 6000 is between 20 and 30 percent faster than HD 5000. It often doubles the performance of Ivy Bridge's HD 4000.

Still, it feels like the HD 6000 should really be able to go faster than it does. The HD 5500 is a little bit faster than Haswell's HD 5000, too, which is strange because it's got far fewer execution units (EUs). Doubling the number of EUs for the HD 6000 and increasing the clock speed doesn't give you anywhere near double the HD 5500's graphics performance. That was the case with Haswell as well—HD 5000 had double the EUs of HD 4400, but not twice the performance.

Our best guess is that the higher-end integrated GPUs need more memory bandwidth to perform to their fullest potential. The Iris Pro 5200 is the same GPU as the HD 5000, but it includes 128MB of eDRAM on the processor package. As a result, Iris Pro 5200 is drastically faster than every single one of the other integrated GPUs on our list. There are certain benchmarks—the GFXBench Manhattan test, the 3DMark Cloud Gate test—in which the HD 6000 and HD 5500 perform very similarly. The HD 5000 and HD 4400 share similar performance in the same benchmarks. That suggests a memory bandwidth problem that a faster GPU with more EUs just can't overcome. Broadwell chips with integrated eDRAM won't show up until later this year—that's when we'll really see what the new Broadwell GPU can do.

Technical quirks aside, how does the new NUC fare when it's actually playing games? One of Intel's taglines for this NUC is that it's "a LAN party that fits in your pocket." Leaving aside the question of whether anyone still has honest-to-goodness LAN parties in the year 2015, the tagline isn't wrong. Some older and lighter titles—the first Bioshock, Portal 2, Minecraft—can be played smoothly in 1080p with all the settings turned up. In Portal, we could even enable some anti-aliasing. It's a really excellent box if you're trying to play through your back catalog.

Slightly more modern or taxing games like Bioshock Infinite give the HD 6000 more trouble; 1080p gameplay is a bit jerky even with all the settings turned down, but you can still play at 720p and medium quality settings. In Skyrim, 1080p gameplay at the Ultra settings level looks like a flipbook, but turn the settings down to low and things are surprisingly smooth (720p and Medium settings work pretty well too).

The HD 6000 doesn't improve enough over the HD 5000 to make previously unplayable games playable (though luckily pretty much everything is playable on both of them). What it will get you is a couple of extra quality settings, or perhaps an extra step up in resolution. It's the difference between a slightly choppy 25 frames-per-second and a smooth 30 frames-per-second. The NUC is emphatically not a 4K gaming box, but if we're talking 720p or 1080p it's surprisingly capable if you manage your expectations properly.

If you're not a gamer, the NUC's new GPU still has some nice improvements for you. Chief among them is 60Hz 4K support over the DisplayPort protocol—the Haswell NUC had a DisplayPort 1.2 connector, but the HD 5000's refresh rate was limited to 30Hz when running at 4K. The HDMI port can drive a 4096×2304 display at 4K, too, but it's limited to 24Hz. As with the Haswell NUC, the Broadwell version can support up to three displays at once if you use am HDMI monitor plus two DisplayPort monitors that are daisy-chained or connected to a capable DisplayPort splitter.

Conclusions

Three iterations in, Intel has figured out what it wants the NUC to be. It's part hobbyist project, part low-end gaming PC, and part miniature workstation. It offers enough power for anyone who doesn't need a quad-core CPU or a dedicated graphics card, and it would be a great drop-in replacement for a mini-tower desktop that's been around for three-to-five years.

As an Ultrabook in a box, the NUCs also serve as showcases for new Intel CPU, GPU, and chipset features. The Broadwell NUC shows us what kind of performance we can expect from solid-state drives in the next year or so. It's better-prepared for our seemingly inevitable 4K future. It manages to keep power consumption about even with Haswell while increasing performance. That said, if you already have a Haswell NUC, there's not really enough new stuff here to merit buying the latest one.

This year, Intel is going to sell more NUCs by increasing the size of the lineup—we saw most of them when the new NUCs were announced. There's a Core i7 model with an Iris 6100 GPU. There are models with space for an integrated 2.5-inch HDD (Haswell versions of these exist, though they weren't introduced until later in the product cycle). There are models specifically for businesses that support vPro and include TPMs and have a cutout in the back for a serial port. Intel's not trying to get you to upgrade your NUC, it's trying to make the NUC workable for more people in more places.

Our main criticisms of the consumer NUC are the same as last year. Because you need to track down and buy some components yourself, it might not be the easiest thing to recommend to a regular PC buyer. Once you've paid for the box, the RAM, and the SSD, you've spent more than you would have on an entry-level desktop or mini PC even though the NUC will usually be the faster computer. We still like it for what it is, though—a surprisingly capable desktop that can fit pretty much anywhere.

The good

• A small, attractive box with good performance. To get a significantly faster computer, you'll need to move up to quad-core CPUs and dedicated GPUs.
• Better performance with similar power usage.
• Refined, smaller power brick.
• 802.11ac Wi-Fi is included.
• Removable lids add new expansion options that don't block your USB ports.
• Plays older games at 1080p with settings turned up. Newer games are mostly playable at lower resolutions and quality settings.

The bad

• You'll have to spend some money to get this performance. Lesser mini PCs can cost half as much.
• Some assembly required. This will appeal to some people but put others off.
• Intel's integrated GPUs need dedicated memory to really shine.

The ugly

• PCI Express SSDs that can make the most of Intel's new chipset features are over twice as expensive as SATA versions right now.

Listing image by Andrew Cunningham