The first thing we noticed when testing the Define R5 is how quiet the two case fans are. These are Fractal's new Dynamic Series GP14 140mm fans and even at full speed they're hard to hear. Suppression of system noise via the sound-deadening foam and ModuVent dampening plates is fairly successful too. No case can cut all noise completely but the Define series has always been one of the best in this regard, and nothing has changed with the R5. Once you have the rest of your system's fans running, the audible difference between full speed and minimum speed is also hard to pick out. This isn't the case with the R4, where at full speed the fans are much easier to hear. As such, it's not really a surprise to see the R5 have slightly warmer temperatures than its predecessor and less variation in temperatures between the maximum and minimum speed settings.
Click to enlarge - The Define R5 can easily be kept very tidy
At full speed, the Define R5 manages CPU and GPU delta T results of 53°C, which puts it almost exactly on par with the Be Quiet! Silene Base 800. Interestingly, neither result is improved by removing the HDD cage, so while you should be able to install multiple HDDs without affecting temperatures too much, it also means that air from the front fan probably doesn't help massively with GPU cooling anyway – a side intake is highly recommended for SLI/CrossFire users.
Lowering the fan speed to 7V and 5V sees the CPU temperature climb by 3°C at each step. The delta T of 59°C at minimum speed is too high for our liking, though as evidenced by the Nanoxia Deep Silence 2 and Cooltek Antiphon it can get a lot worse. Nevertheless, medium is a good compromise as the noise difference between it and minimum is negligible anyway. Meanwhile, the GPU climbs from 53°C to 54°C at medium and 55°C at minimum, which again indicates that the front fan isn't doing all the much for temperatures. This is bad in the sense that your GPU is mostly left to fend for itself, but good in that if you have a decent GPU cooler (which you should if you're aiming for a low noise build), then you can get away with using the lower fan speeds with little concern.
Click to enlarge - Removing the front HDD cage had no impact on temperatures
In most ways the Define R5 feels like a very natural evolution of the Define R4. The launch price is effectively the same, so we have few complaints here. The £90 price tag for the windowed version does look a little steep (and you'd lose a fan mount), but equally adding a window yourself would be more costly. At just over £80, the standard Define R5 is better than the Be Quiet! Silent Base 800 in terms of value – the latter may include an additional fan, but this doesn't help it cool any better, and the R5 is equipped with fan control and a much more flexible interior for storage and water-cooling.
We have few complaints about the Define R5. There are a few slip ups, such as the size of the top cable routing holes, and we really wish dust filters had been included for the ModuVent-backed fan mounts, especially the side one. However, generally speaking the case is well built and very easy to work with. Fractal has definitely played it safe with the design – there's nothing particularly innovative or exciting here, and we could've predicted most of the upgrades over the R4 before even seeing the new chassis. However, Fractal is not alone here; as we said before the case market in general has become somewhat stagnant. There's also of course the argument of “if it ain't broke, don't fix it”, and given the success of the Define series thus far Fractal would arguably have been unwise to mess with the design too much. In summary, the Define R5 is reliably good, and that's hardly a complaint – this is still the case get if you're gunning for low noise and minimalist looks.