Close to two years after the release of the Razer Viper 8K, mice capable of true 8000 Hz polling are still few and far between. Being Atompalm's debut mouse, the Hydrogen joins this rather exclusive club. Unlike the Viper 8K, and much like the Zaunkoenig M2K, the Hydrogen utilizes PixArt's PMW3360 sensor. While an older model, the 3360 is still perfectly capable of 8000 Hz polling, with one caveat explained further below. Sensor performance is very good on the Hydrogen: CPI deviation is virtually nonexistent, general tracking fine, and motion delay is very low as well. Polling is generally stable, although I did notice two flaws: First, even though there aren't any outliers, variance is higher than average on the Hydrogen, no matter which polling rate is set. Second, all polling rates are consistently above target—that is, instead of 1000 Hz, 1050 Hz are averaged, or instead of 2000 Hz, 2090 Hz are averaged, and so on. In my book, exceeding the target value is better than falling below it, though meeting the target would be ideal. The only exception to this is 8000 Hz, which falls short of the target value on the Hydrogen. Unrelated to that is a limitation of the 3360 in regard to 8000 Hz polling. The 3360 has multiple framerate modes, and only the highest one provides enough capture frames for 8000 Hz polling. Hence, one either needs to move the mouse sufficiently fast or use a higher CPI step to effectively force the mouse into said framerate mode. Thankfully, the Hydrogen is using the latest SROM for the 3360, which is why up to 3500 CPI can be used without motion delay being negatively affected. In short, I consider this a non-issue, so for all intents and purposes, 8000 Hz works perfectly fine on the Hydrogen.

Of course, 8000 Hz polling not only applies to sensor but click and scroll events as well. On the Hydrogen, latch debouncing is used for all except the side buttons, which ensures the lowest possible click latency without running the risk of double-clicking due to improper switch debouncing. And indeed, at a measured click latency of 0.1 ms, the Hydrogen manages to achieve among the lowest click latency of any gaming mouse currently available, matched only by the Razer Viper 8K and Zaunkoenig M2K. A neat feature of the Hydrogen is that click and scroll events are always polled at 8000 Hz, no matter which polling rate the mouse is set to. In fact, instead of polling rate proper, the sensor target rate is adjustable on the Hydrogen. Hence, it is possible to run the Hydrogen at 250 Hz or any other non-8000 Hz polling rate while still enjoying the benefits of 8000 Hz click latency. Truthfully, the same is true of the Viper 8K and M2K, but the Hydrogen provides the user with a much greater selection of possible polling (sensor target) rates. Rates such as 7000, 3000, 125, or even 63 and 31 Hz are all available on the Hydrogen, allowing the user to experiment. Furthermore, if 8000 Hz happens to be too taxing for a specific game, one could drop to 7000 Hz first, then 6000 Hz, and then 5000 Hz, without having to go to 4000 Hz right away, as other 8000 Hz mice would force one to.

In short, while not flawless, the technical execution on the Hydrogen is very good. Unfortunately, the same cannot be said about the mechanical side of things. On the bright side, at 48 g the Hydrogen is among the lightest mice available currently. Holes have been utilized to achieved that weight, but they only extend to the rear and bottom of the mouse, leaving the finger contact points solid. Shell integrity is good, as creaking or flexing are minimal, though actuating the side buttons by applying lateral force to the sides is possible, even without using excessive strength. Unfortunately, the real issue lies with the buttons. For the main buttons, Japanese Omron D2F-01F switches are used, which, while somewhat muted in terms of feedback, are durable and more than adequate switches. The button design however, results in a ridiculous amount of pre-travel, which has the buttons feel very mushy and spongy. In fact, the pre-travel is bad to where the mere act of clicking requires extra effort, as despite the switches not being heavy, the sponginess of the main buttons makes bottoming them out just by lightly tapping close to impossible. Aside from the buttons feeling horrible, there is also the fact that this level of pre-travel introduces significant real-world latency, which comes on top of the 0.1 ms of click latency on the hardware level. The side buttons aren't much better. While their pre and post-travel is close to nonexistent, they are exceedingly stiff, which is doubly irritating on a mouse this light. The stiffness leads to them being noisy, too, and their position isn't entirely optimal, either. The Hydrogen is not a small mouse, so those with smaller hands may find themselves struggling to reach the forward button without adjusting their grip. The CPI button has a different issue, namely being completely loose. Basically, whenever the Hydrogen is moved, the CPI button will rattle around, to where it becomes quite aggravating. The only solution is to remove it altogether, but then switching CPI becomes impossible, as the software doesn't offer this functionality. Depending on its current position, the scroll wheel isn't entirely stable, either, though isn't half bad aside from that. Noise levels are mostly under control, and tactility is quite good, allowing for controlled scrolling. Being aluminium, the scroll wheel feels sturdier than the usual plastic wheels, and durability is another plus.

Still, the button issues and rattling make it quite difficult to enjoy the Hydrogen. It's a pity, since the Hydrogen also checks several boxes in other areas. The cable is very flexible for being fully shielded, and easily on par with the M2K, whose cable is best in class for a 8000 Hz mouse. The feet are very good too, though I don't think they're actually 100% PTFE, as they'd appear more translucent if they were. Either way, glide is very good, and their above average thickness ensures good longevity. The software is quite barebones, but works well and has all the important options, though being Chromium-based, I've experienced random and fairly heavy CPU and GPU utilization spikes.

If Atompalm finds a way to revise the shell in such a way that the rattle and main button pre-travel are eliminated, the Hydrogen could be counted as a solid option for enthusiasts. Luckily, I have been informed by Atompalm that future batches will receive improvements to the shell and PCB to get rid of the main button pre-travel, CPI button rattle, and scroll wheel rattle, along with changing the side buttons to Kailh GM 8.0. Currently however, it is difficult to recommend the Hydrogen, especially when considering the pricing and comparing it to the (ambidextrous) competition. In terms of pricing, the Zaunkoenig M2K is in an entire different universe altogether, and the technical execution is a bit better, but most importantly, there is no rattle or main button pre-travel, despite the M2K weighing half of what the Hydrogen weighs, while being half as large of course. At $79.99, the Razer Viper 8K is a decent bit more affordable than the Hydrogen, has 8000 Hz implemented flawlessly, the same click latency, infinitely better buttons and no rattle, albeit at a much higher weight, along with the burden that is Razer Synapse. The EVGA X12 is the budget option at $49.99, with 8000 Hz polling that is roughly on par with the Hydrogen in terms of implementation, worse click latency but better buttons, a higher weight, and a very weird shape.