Building a mini-ITX system, particularly one intended to offer extreme performance, is always going to be a challenge. We've already shared some of the many head-scratching moments we faced as we put this PC together. But getting it pieced together was only half the battle. We had to push it hard to see if it would hold together under stress. And as we've already suggested, we learned a thing or two once we hit the power button.
First we had to get a handle on Intel's new Skylake platform. Using an early UEFI that shipped with the motherboard, we found that stock voltage was surprisingly high, around 1.28V. That leads to unnecessary heat and power use. It wasn't until we flashed the board with the latest UEFI (from November 2015) that stock voltage dropped to more reasonable levels (around 1.24V). That's still much higher than previous Ivy Bridge and Haswell systems, and it meant identifying the best overclocking settings would be a bit of a challenge. Additionally, we found that Multi-Core Enhancement, which runs the cores at Turbo speed (4.2GHz) under all loads, is no longer available on its own - you must also engage the XMP memory profile. This probably came as a result of complaints (mostly from reviewers) that motherboard manufacturers were running CPUs at overclocked settings to juice the benchmarks, without informing end users.
In any event, the 6700K runs at 4GHz in anything but a single-core load, which basically doesn't exist in the real world. This is unlike previous Core i7 chips, as well as other chips in the Skylake series, which Turbo to something higher than their rated speed even under maximum load. So stock speed is 4GHz in our benchmarks. With a bit of experimentation, we were able to take it the chip to 4.4GHz with a -0.1V voltage offset. Yes, you read that right, we overclocked and undervolted! When overclocking, however, the motherboard does some of its own voltage adjustments, so we ended up at around 1.2V when overclocked. This was as high as we were comfortable going, because under our Intel Burn Test stress test, the system came perilously close to the 100 °C throttling threshold. Remember, we're dealing with an ultra-slim chassis with no active cooling, and a very compact CPU cooler. Overall, this just isn't the system to hone your competitive overclocking skills with.
Luckily, we had plenty of experience with our GTX 980 Ti, so we knew exactly what it could do. We first benched it at stock speeds, which for our sample translate to 1202MHz core under load and 7000MHz memory (not all stock-clocked cards hit the same clocks, surprisingly!). We then took it straight to 1400MHz (that's a +200MHz offset in your favorite GPU tuning application), plus a 400MHz memory offset to hit 7800MHz (note the double-data rate math there). Because of the excellent cooling afforded by the practically open-air video card compartment, our GTX 980 Ti fared just as well in the RVZ02 case as it did in our big ATX test bench cooled by a multitude of high-speed case fans.
We also had a bit more luck with memory overclocking than we've had with the ultra-high-end Haswell-E platform. We took our DDR4-3000 kit straight to 3000MHz, up from the default 2133MHz, dialing in sub-timings of 15-15-15-35-1T, at a voltage of 1.35V. Note that by default our sticks, which were designed for Haswell-E motherboards, wanted to use a silly 125MHz strap in order to engage the XMP profile, so we simply set it manually. Skylake, unlike Haswell-E, allows for speeds above 2666MHz without resorting to overclocked straps.
So, how does this system perform? In 3DMark, we were able to hit a score well beyond what any previous quad-core system could achieve, even with the modest CPU overclock. Focus on the yellow bars, which represent this build as overclocked. For comparison purposes, we've included the stock-clocked data, as well as numbers from our Project ITX build, which utilized the shoebox-style Silverstone SG08 case with two different component configurations.
Impressive. We were running a 10% overclock on the CPU, cooled by a short-stack cooler with a slimline 100mm fan. And it turned in a perfect 10% gain in the Physics test (we love 3DMark for its accurate, linear CPU benchmark!). And our video card achieved a nice 17% overclock, which translated to a 15.1% performance increase. And this was all in a case less than 4" thick. Wow! And it was all really efficient, too. At idle, the system drew just 40W, while under a full CPU/GPU load in the 3DMark Combined test, it hit 370W. As we said before, this didn't even come close to stressing the power supply. How about temperatures? In the Intel Burn Test stress test, our Core i7-6700K hit 78 °C at stock speed and 93 °C overclocked, which is at the edge of our comfort level, but luckily will never be seen in typical use. Our idle and gaming data below provide a more real-world look at how the system performs, again compared to our Project ITX systems:
The results are pretty fantastic given the overall performance. Keep in mind that the GTX 980 Ti shuts off its fans at idle, as does the Silverstone power supply, making them both silent. And the CPU fan ran at only 1000RPM at idle, making it whisper-quiet. At load, the system was still very quiet. Note that the older Project ITX system used a passive CPU cooler, aided by the Silverstone SG08's active case cooling, essentially the reverse of the RVZ02-based build. In just about every metric, the RVZ02's thermal performance is superior.
Here you can see our ITX build placed next to one of our most compact ATX builds, based on the sleek NZXT S340 chassis. Despite being able to pack in nearly all the same hardware (sans dual video cards and a big ATX PSU), the Raven looks quite petite here. And that's what really makes it a fantastic pick for PC builders ready to accept its limitations. And there are several.
We've covered the cabling issues, the restrictions on CPU cooler height, and the power supply noise. But there was one other issue we identified when we closed up the case. Note that we flipped the system upside-down in the photo here to orient the CPU near the top, which is how most cases are oriented. We did this once we realized that Silverstone had made another poor design choice, which you can see in the photo to the left. In short, Silverstone somehow decided it would make sense to vent the power supply into the bottom of the case, which is nearly devoid of exterior vents, and then to have the user mount the case on feet that partially block the few vents that do exist. In our opinion, this is a recipe for long-term power supply failure, and seeing no significant consequences for compontent temperatures, we decided to run our system in the flipped orientation. It even places the power button up near the top, which makes it a whole lot more convenient to reach if the system is on the floor.
So, what have we learned? Time and time again, we've come to realize that building a mini-system, especially an extreme mini-system, can be a bit tricky with off-the-shelf parts. And it all starts with the case you choose. Silverstone produces more small form factor cases than any other company, which makes it a natural choice when seeking out just the right ITX case. There's just no doubt that they are incredibly unique and innovative, and it's clear that Silverstone has some of the best CAD designers in the business.
It's also clear, however, based on our testing of half a dozen Silverstone cases over the years (all purchased at retail, we should add), that Silverstone has no one on staff that actually builds PCs. In fact, we're pretty sure many of its cases are never even powered on by Silverstone with actual components and cables installed, because every single Silverstone case has some form of fit issue that calls into question its advertised component compatibility. Do we love Silverstone cases for their daring design? Yes, we do, but builder-friendly they are not. And Silverstone continues to toe the line of false advertising in the specifications it provides, with many theoretical component combinations it lists being impossible to install in practice. We're concerned enough about this problem that we'll no longer be recommending Silverstone cases that we or one of our intrepid readers haven't fully vetted.
All that being said, there's definitely a great market for the Silverstone RVZ02 case, and that is in home theater and couch gaming applications. It's by far the slimmest case on the market that can fit high-end gear, and while we recommend limiting it to mid-range gear, that's still going to be more then enough in an HTPC setup. There's certainly no "HTPC" case outside of the ITX arena that comes anywhere near the svelte profile of the RVZ02. And by the way, while we didn't show them in use in our article, the case does come with four rubber feet that can be affixed to one side of the case, allowing it to be positioned horizontally, as you'd do on an AV rack. At just 12 liters, it's ultra-optimized for this type of setup - technically it's even smaller than the 14.8-liter SG08 used in Project ITX, although it feels larger in hand due to being so tall and deep (making it far less portable, by the way).
In the end, it may seem that we harped a lot, maybe a bit too much, on the Silverstone RVZ02 case, and to a lesser extent on the Silverstone power supply. But in reality, the ITX experience very much comes down to the case and power supply you use, as they determine so many of the parameters of what you can do. We certainly applaud Silverstone for thinking out of the box with its multitude of small form factor offerings; we just wish they'd pay more attention to what goes in the box.
Building with ITX cases is always going to involve some give and take, and we're here to make clear exactly what enthusiasts are in for, or up against, when they choose to take on their next ITX build. We've previously profiled some interesting takes on bookshelf ITX PCs by Antec and In-Win, the palm-sized Intel NUC, as well as the aforementioned Silverstone SG08. None of these cases is perfect, but they each have their application. We'll be sure to profile other cases in the future as we continue to expand our coverage of the ITX universe. For all of our latest small form factor recommendations, definitely stop by our Small Form Factor Buyer's Guides, which are updated monthly!
Update: Since publishing this guide, we've put together our Extreme Gaming ITX PC Assembly Guide using a case that is a better match for ultra-high-end video cards and extreme overclocking. Check it out if that sounds like what you're looking for!