Spoiler



anyway, the viper ultimate's 3399 sensor is the current leader of this contest, going up to 20000dpi and 650ips (16.5m/s) tracking speed. again, it is not a bad thing that the sensor is capable of it, but 20000dpi is far beyond what anyone needs. (and actually, as will be discussed later, something funny happens when using the viper ultimate at high dpi's). similarly, 16.5m/s is well above any tracking speed in any sort of gameplay: you can play on 1m/360 sensitivity in an fps game and i guarantee that you will not be able to aim consistently beyond 5-6 m/s.



apart from these unimportant numbers, there are two important aspects to the tracking performance of a mouse

1. positional accuracy:

if you move the mouse from point A to point B, how reliable is the sum of all the counts of motion reported by the mouse? this is something difficult to quantify without specialized equipment that moves the mouse in a well defined path. but throughout the years, we have devised tests, often involving mspaint, that can reveal flaws in positional accuracy: e.g. angle snapping, jitter/ripple artifacts, and other things i cannot remember right now. there are also tests such as



my feeling is that throughout the last few years, logitech has especially focused on testing and pushing the boundaries of positional accuracy. for instance, the circle tests shown here:



2. timing accuracy:

first, to keep some perspective, try the following:

a) use 60hz refresh rate. move the cursor near the top of the screen and near the bottom. do you notice a difference in input lag?

b) use 60hz refresh rate again. on windows 7 (with aero, not a classic theme), 8, or 10: drag the titlebar of a window around. compare the responsiveness of the cursor in normal use and when dragging a window around. is there a difference?

c) compare the motion of the cursor at 125hz polling rate to 1000hz.



in (a) and (b), the difference in input lag in the scenarios can be up to one refresh cycle (16.7ms), yet you probably found that the differences are quite subtle, if you noticed at all. in (c), when using 125hz, the full-chain input lag is constantly fluctuating between X and X + 8ms, where X is the full-chain input lag if the mouse runs at infinite polling rate. yet the motion of the cursor is very obviously choppy.



the point is that it is not only the average amount of latency that matters, but how much it fluctuates. for example, 15ms of constant latency might be better than latency fluctuating between 5ms and 12ms.



here, we are concerned only with the contribution of the mouse to the total input lag. in other words, when the mouse sends a report over usb with motion data, how old is that data? and how much fluctuation is there in this latency?



more details concerning this will be provided in the sections where this is tested. the standard specifications of resolution (dpi) and max speed (ips or m/s) are traditionally indications of the tracking performance of a sensor, by quantifying the limitations of a sensor's performance. the performance of modern sensors, such as pixart's 336x sensors, is well past the point where these numbers matter. of course, in and of itself, larger numbers are not a bad thing, and within a company's range of sensors, the higher-end sensors do have higher specifications. but with modern sensors, companies one-upping each other with every new sensor has really become a pissing contest, kind of (but not literally) like the megapixel wars.anyway, the viper ultimate's 3399 sensor is the current leader of this contest, going up to 20000dpi and 650ips (16.5m/s) tracking speed. again, it is not a bad thing that the sensor is capable of it, but 20000dpi is far beyond what anyone needs. (and actually, as will be discussed later, something funny happens when using the viper ultimate at high dpi's). similarly, 16.5m/s is well above any tracking speed in any sort of gameplay: you can play on 1m/360 sensitivity in an fps game and i guarantee that you will not be able to aim consistently beyond 5-6 m/s.apart from these unimportant numbers, there are two important aspects to the tracking performance of a mouse1. positional accuracy:if you move the mouse from point A to point B, how reliable is the sum of all the counts of motion reported by the mouse? this is something difficult to quantify without specialized equipment that moves the mouse in a well defined path. but throughout the years, we have devised tests, often involving mspaint, that can reveal flaws in positional accuracy: e.g. angle snapping, jitter/ripple artifacts, and other things i cannot remember right now. there are also tests such asto check for "accel" (dependence of dpi on tracking speed).my feeling is that throughout the last few years, logitech has especially focused on testing and pushing the boundaries of positional accuracy. for instance, the circle tests shown here: https://www.cnet.com/reviews/logitech-g900-chaos-spectrum-preview/ 2. timing accuracy:first, to keep some perspective, try the following:a) use 60hz refresh rate. move the cursor near the top of the screen and near the bottom. do you notice a difference in input lag?b) use 60hz refresh rate again. on windows 7 (with aero, not a classic theme), 8, or 10: drag the titlebar of a window around. compare the responsiveness of the cursor in normal use and when dragging a window around. is there a difference?c) compare the motion of the cursor at 125hz polling rate to 1000hz.in (a) and (b), the difference in input lag in the scenarios can be up to one refresh cycle (16.7ms), yet you probably found that the differences are quite subtle, if you noticed at all. in (c), when using 125hz, the full-chain input lag is constantly fluctuating between X and X + 8ms, where X is the full-chain input lag if the mouse runs at infinite polling rate. yet the motion of the cursor is very obviously choppy.the point is that it is not only the average amount of latency that matters, but how much it fluctuates. for example, 15ms of constant latency might be better than latency fluctuating between 5ms and 12ms.here, we are concerned only with the contribution of the mouse to the total input lag. in other words, when the mouse sends a report over usb with motion data, how old is that data? and how much fluctuation is there in this latency?more details concerning this will be provided in the sections where this is tested.

Spoiler



anyway, they rightly emphasize up the importance of timing accuracy and the importance of synchronization between usb polls and whatever is going on inside the mouse. so let's discuss this first.



in a wired mouse, there are 3 processes that have (potentially) different timings:

1) USB communication between the computer and mouse

2) SPI communication between the microcontroller (mcu) and the sensor

3) sensor frames



for (1), the mouse can request a certain polling interval. the computer might not respect this, which is how old mice can be "overclocked" to run at 1000Hz. but more importantly, the mouse has no control over whether the usb poll arrives 0.1ms late or 0.1ms early. the timing of usb polls is entirely dictated by the computer. the computer asks for data, and the mouse responds.



just to be clear, usb polling intervals are extremely stable, at least for the computers i have checked (so my desktop and laptop). here's a video of my oscilloscope connected to one of the data wires of a usb cable, showing that the jitter is less than a few nanoseconds.







g pro 3366, 5 tries:

-32, 61, 10, -27, -18



viper ultimate, 5 tries:

15, 16, -18, 35, 1



yup, nothing to report here "motionsync" is probably the most interesting advertised feature of the viper ultimate. what exactly it is is not completely clear. the info on razer's website and Razer_TheFiend's posts are all a little vague and i can't tell if they're not even all consistent.anyway, they rightly emphasize up the importance of timing accuracy and the importance of synchronization between usb polls and whatever is going on inside the mouse. so let's discuss this first.in a wired mouse, there are 3 processes that have (potentially) different timings:1) USB communication between the computer and mouse2) SPI communication between the microcontroller (mcu) and the sensor3) sensor framesfor (1), the mouse can request a certain polling interval. the computer might not respect this, which is how old mice can be "overclocked" to run at 1000Hz. but more importantly, the mouse has no control over whether the usb poll arrives 0.1ms late or 0.1ms early. the timing of usb polls is entirely dictated by the computer. the computer asks for data, and the mouse responds.just to be clear, usb polling intervals arestable, at least for the computers i have checked (so my desktop and laptop). here's a video of my oscilloscope connected to one of the data wires of a usb cable, showing that the jitter is less than a few nanoseconds.but not needing to go into a game.g pro 3366, 5 tries:-32, 61, 10, -27, -18viper ultimate, 5 tries:15, 16, -18, 35, 1yup, nothing to report here

disclaimer and acknowledgement: Razer_TheFiend from Razer R&D contacted me and sent me this mouse for free for testing.disclaimer 2: over the last two weeks i have been in contact with TheFiend via email to discuss various aspects of tracking performance. partially as a consequence, some changes and improvements have been made to the firmware. i am currently running a version of the firmware that is still in testing and should be released to the public soon. some of my early replies to this thread discuss issues with older firmware that have since been resolved.note: this post is mostly done, but i will update it as i learn more from messing around with the mouse/sensor and when there are future firmware updates. although it shares the same physical package, the 3399 is completely different from 3366/3360/3389/whatever, so there's still lots to figure out.introduction to this topictiming accuracy, wired modetl;dr: as expected, not an issue.will test later. they're optical switches, so in theory they should be perfect.0. nice to see that they target low weight but without stupid holes on the outside. also i like how the razer logo is barely visible if the led lighting is turned off.1. build quality seems good in general. not sure how durable rubber sides are.2. not a fan of the feel of these switches. it's not exactly pretravel but the switches are too soft before actuation. the click itself (how much motion there is from just before and just after actuation) does not feel deep enough for my liking. i tried to base these observations without regards to the sound of the clicks, by wearing iem's so that i don't hear the switches.anyway it's possible to get used to these switches after a while, but whenever i go from the viper ultimate to my g pro (3366) i can't help but think to myself: wow g pro switches are so nice...oh actually, the side buttons on the viper ultimate feel better than the main buttons lol3. wheel is alright. there's a bit of looseness from the right side of the wheel that goes into the U-shaped notch. encoder's detents are a little too strong for my liking but it should get lighter with use.4. charging dock is way more convenient than having to plug in a cable5. the door for the usb dongle is easier to use and lighter than logitech's magnetic door.the usb dongle is not labelled with anything particularly identifying it as a dongle for the viper ultimate. i have no idea what razer's plans are but if they release another wireless mouse, it's going to be confusing unless they use a different shape or have something more than a faint razer logo on it.well, many of us here like to make fun of razer for their rgb lighting, for synapse, and for whatever else razer is known for. this time, not only did they made a more than decent mouse with a new sensor that isn't just the current winner of the dpi wars but also brought along some technical innovations. the mouse and its firmware are not perfect and have room for improvement, and there is a silly dpi bug that remains to be fixed. from my experience at least, their firmware/electronics teams have been very responsive to feedback, so i do expect them to improve things in the coming weeks. i used to think that logitech is the only company concerned with the minutiae of mouse performance. razer certainly has shown that they do as well and in fact the viper ultimate does some things better than logitech's wireless mice.notes:torx t6 screws under the 4 main feet. i used a 1mm flat screwdriver to pierce a hole in each foot over the center of the screw. to open up the shell, you also need to release a hook on each side. (unscrew all 4 screws a bit and then gently wedge in a credit card or fingernail or something)main pcb is held by only 2 screws, even though there is another screw hole under the left switch. this does not appear to be an issue.kailh mechanical encoder450mAh lipo battery