Primarily known for its PSUs, fans, and cases, be quiet! releases their first gaming mice with the Dark Perk Ergo and Dark Perk Sym. In terms of specifications, these are basically the same, differing only in their shape and resulting weight. The shape of the Dark Perk Ergo leans towards the Logitech G403 family of shapes, albeit much slimmer at the front and smaller in general. At 54 g, the Dark Perk Ergo is largely competitive with a direct competitor such as the likewise G403-adjacent Teevolution Terra Pro, which weighs 51 g while being larger and having a fully solid shell. By contrast, the Dark Perk Ergo doesn't have a fully solid shell, as the bottom features four moderately large cutouts for weight-saving purposes. However, the rationale behind this design appears somewhat dubious: when looking inside the mouse, one can see that the main PCB is needlessly spacious, as if it had been widened for the sole purpose of being able to write "be quiet!" and "Dark Perk Ergo" on the underside of the PCB, which then can be seen through those cutouts. This item aside, build quality is largely in a good spot: there is no creaking or flexing of the shell when applying lateral pressure, and actuating the side buttons by pressing below the side buttons cannot be done regardless of force. When shaking, however, a rattle comes from the main buttons. In order to ensure structural rigidity, the Dark Perk Ergo employs a similar concept as the DAREU A950 Wing by inserting a plastic assembly across the width of the top shell, though the one in the Dark Perk Ergo is larger and also carries the battery.

Speaking of the buttons, the Dark Perk Ergo utilizes Omron D2FP-FN2 optical switches for its main buttons. These are known for their exceptionally snappy response as well as a pronounced metallic "ping." The latter is definitely present and felt on the Dark Perk Ergo, though for some reason, actuation is somewhat muted and dampened compared to other D2FP-FN2-equipped mice. In addition, significant lateral button movement can be provoked on the left main button in particular, resulting in the aforementioned rattle when shaking, though during actual usage this remains largely unnoticeable. The side buttons have been outfitted with 2-pin, low-profile switches from TTC, which score with low to moderate pre-travel and minimal post-travel, along with even actuation. The scroll wheel comes with TTC's near-ubiquitous "Gold" encoder, which tends to have significant unit-to-unit variance, though the 11 mm size found in the Dark Perk Ergo lands at the upper end of the possible spectrum: noise levels are under control, and tactility is very good, with the individual steps being clearly defined. The feet are made of white-dyed pure PTFE and glide well, and a set of replacement feet is included in the box.

The Dark Perk Ergo comes with PixArt's PAW3950 sensor alongside a Nordic nRF54H20 MCU, which thus far has mostly been seen on enthusiast-level offerings such as the Razer DeathAdder V4 Pro or ASUS ROG Harpe II Ace. The 54H20 provides a USB high-speed PHY, allowing for true 8000 Hz polling in both wired and wireless operation. Unfortunately, the Dark Perk Ergo is let down by subpar firmware. The modest CPI deviation of -2.5% is easily corrected and therefore not an issue. An oddity is a setting called "Power Saving Mode." This one only takes effect in wireless operation, where it changes the sensor run mode from the default HP (High Performance) mode to LP (Low Power) mode. The problem is that on the Dark Perk Ergo, LP mode runs at a sensor framerate of below 1000 Hz, making it impossible to reach a polling rate of 1000 Hz. In practice, there is no real reason to use this setting anyway, but it underlines how half-baked the firmware is in many places. There appears to be some issue with sensor framerate in general, as all sensor run modes run at framerates that are roughly 30% lower than normal.

Polling stability is a big issue on the Dark Perk Ergo in general. In fact, the Dark Perk Ergo is one of those peculiar mice that don't have a single polling rate that could be considered fully stable. In wired operation, every polling rate exhibits various types of noise, except for 8000 Hz which suffers from large off-period polls instead, often missing polls by more than 3 ms. Furthermore, 125, 250, 500, and 1000 Hz all suffer from an issue whereby the target rate is missed by roughly 28%—i.e., instead of 125 Hz, 90 Hz are averaged, instead of 250 Hz, 180 Hz are averaged, and so on. 2000 Hz likewise should rather be called "1600 Hz," as 0.625 ms instead of the target interval of 0.5 ms are averaged. Wireless operation fares even worse, with 125, 250, 500, and 1000 Hz suffering from elevated variance and frequent off-period polls, which is also true for 2000 and 4000 Hz, albeit with even larger off-period polls, often exceeding 6 ms. Finally, 8000 Hz may be considered broken, as the off-period polls are pronounced to where the motion response ends up being non-linear. Due to this issue, I haven't even been able to determine motion delay at 4000 and 8000 Hz wireless, though 2000 Hz at least fares quite well at an advantage of 0.8 ms over the Logitech G403 (control subject) without MotionSync. "Without MotionSync" is an important qualifier on this mouse, as the Dark Perk Ergo is also struggling with MotionSync in general, in that the motion delay introduced by enabling it is far greater than it should be. In general, there are so many issues with polls being missed, elevated variance, and various types of noise that I often haven't even been able to determine motion delay at all, which is certainly not a good thing.

On the latest firmware, wireless click latency has been greatly improved. The average now lands at around 1.3 ms across all polling rates. "Approximately" is important here since standard deviation is still very high, resulting in accordingly high run-to-run variance. It is not uncommon that a 0.68 ms click is followed by a 2.80 ms click, then a 1.68 ms click and another 2.80 ms click. Hence, while the average is fine, the large variance makes it difficult to achieve consistent in-game click timing still. In wired operation, the Dark Perk Ergo averages 0.5 ms, which still falls short of other 8000 Hz wired mice, but at least is competitive. For the record, the Dark Perk Ergo has debounce time adjustment, though this does not apply to the main buttons, which default to 0 ms no matter what. A slam-click prevention algorithm is present and implemented flawlessly.

On the Dark Perk Ergo, configuration can either be done in be quiet!'s IO Center software or in a web driver. The web driver connects through WebHID and therefore is restricted to Chromium-based browsers such as Chrome or Edge. In terms of functionality, the software and web driver are essentially equivalent, providing all the relevant settings and being pleasantly bug-free. IO Center occupies around 80 MB of RAM, which is in the acceptable range. At 1000 Hz, be quiet! cites up to 110 hours of battery life, but verifying this claim is difficult as the battery charge indicator found in the software and web driver is essentially useless. Instead of a percentage, the indicator shows multiple segments, which are incredibly hard to visually parse due to the symbol being miniature-sized and poorly rendered. With a magnifying glass, I've been able to tell that after three hours of continuous usage at 8000 Hz, the indicator showed four out of five segments, which would suggest around 15 hours of expected battery life at 8000 Hz. Ultimately, however, this is really just guesswork, though if true, 15 hours at 8000 Hz would be incompatible with the claim of 110 hours at 1000 Hz. At the same time, given the use of a 54H20 MCU and a 400 mAh battery, 110 hours would really be the minimum expected battery life. Charging speed is distinctly average at a bit more than 0.2 A, and the same goes for the charging cable, which is at least flexible enough to allow playing while charging without feeling overly restricted.

At $109.99, the Dark Perk Ergo isn't unreasonably priced given its features and components. At the same time, the Teevolution Terra Pro costs marginally less with the 8K dongle while being the plain superior mouse, outclassing the Dark Perk Ergo in the performance department in particular. As such, I have a really hard time making a case for the Dark Perk Ergo. The shape isn't unique enough to compensate for having to deal with the performance issues, and while the presence of a Nordic 54H20 is commendable, older mice with the 52840 still perform better than this implementation. Accordingly, I'd steer clear of this one.