Review of the Logitech G502 Proteus Core Gaming Mouse – Improved ergonomics over the Logitech G303

Pros: Accurate sensor, weight adjustment, ergonomics, customisable buttons, scroll wheel
Cons: No colour customisation, software limitations

Build Quality: 8.5/10
Design & Looks: 10/10
Performance: 10/10
Software: 8.5/10
Value: 10/10
My final Rating: 9.5/10

Purchase Date: December 2015
Purchase Price: £55

Logitech G502 Mouse - Side view

After having reviewed the Logitech G303 mouse, which shares the same Pixart PMW 3366DM sensor as the G502, I thought to buy myself the more ergonomic G502 – I bought it for £35 (as it was on a deal on AmazonUK) – as prices fluctuate from £70 to £35, I thought to review it at the £55 price tag, which is a mid-point between the two.
The mouse can be found on AmazonUK for around £55 & AmazonUSA for around $55 (note the prices do heavily fluctuate) – as I am a UK based reviewer I will be reviewing it at the £55 price tag.

As a note: I didn’t receive this for review nor receive any promotional discount – I am reviewing it as a purchase as I thought it would be useful to readers to know the differences between the two mice. On top of that I bought the mouse as the ergonomics of the G502 looked better for my needs and hand size (17-19cm from middle finger to palm).

Here’s my video review of the mouse:

Now let’s get into this written review!

Full specification and a description of the keyboard can be found on Logitech’s website.

Build quality

The build quality of the mouse is good, albeit not perfect.

First off a quick note on what you get inside the box: The mouse, a small case with weights included and a set of manuals.

The switches found under the left and right buttons are like the ones found in the G303 and are very precise to clicks. The mouse is terminated by a braided USB cable – the added touch of the braided cable is nice when using the mouse on various surfaces.

Logitech G502 Mouse - Weights

The mouse itself has a little more weight in comparison to the G303, where it has a “mouse only” weight of 121g vs the G303’s weight of 87g.
Unlike the G303, the G502 comes with weight adjustments which are cleverly placed underneath the mouse. There’s a total of 5 weights that can be added to the G502, with each weight adding an additional 3.6g to the overall weight of the mouse – giving the mouse a potential of 18g extra weight. Having gotten used to the G303’s weight it was hard for me to adjust to the G502’s stock weight. I feel it would have been great if the mouse weighed just a little less (for example 100g for the mouse only) – I feel this weight would have been the perfect stock weight to have for the mouse. However, as this is all subjective, it’s more a matter of opinion than anything else.

I should also mention, the mechanism to close the back enclosure is magnetic, which makes it very easy to add and remove the weights.

Logitech G502 Mouse - Underneath

Moving on to the surface of the mouse, which like the G303 has a matte coating on it, meaning it’s non-slip and doesn’t pick up fingerprint marks all over it – unlike other mice I’ve previously reviewed.
I should also mention that there are lights found on the G502, where there are the DPI lights and the Logitech “G” logo light which both light up in blue. I’ll speak a little more about the lights in the design section of this review.

I would like to mention the “mechanical microswitches” and the “metal spring left/right button tensioning system” found under the left and right buttons. These two buttons are rated at “20 million clicks” which is quite a lot of clicking you’ll need to do to wear out this mouse. However to me the specs aren’t what’s interesting, but the actual feel of these switches. Just as I felt with the G303, the G502 one-tap shots in Counter Strike: Global Offensive (CSGO) became a lot better. This was the result of those switches being accurate and precise on the click. It might seem trivial to some, but when gaming at a competitive level that minor difference in a click can make a huge difference and for me it was very much the case. It’s hard to describe, but to put it simply: The clicks were precise and on-point with what I was trying to do.

Logitech G502 Mouse - Front side with hand

This might not be particularly interesting for most, but for those gaming in MMORPG or RTS games, such as Dota 2 or League of Legends, the clicks per minute you can achieve is insanely high with the G502. I should also note that the mouse clicks weren’t loud or sharp sounding.

With all that said, I did find a major flaw with the mouse – where when I looked around the Internet found other people also complaining about the same issue. The problem I found came from the left and right buttons of the mouse rebounding and creating an unwanted spring-esk sound. After looking around the net, I found people talking about “sticky fingers” – I don’t particularly have sticky fingers, but do sweat a little from time to time and this is what causes the button to “stick” to your finger and you lift off the mouse, creating an odd and unwanted spring sound. I have yet to experience this problem with any other mouse I’ve owned or tried – and it was really disappointing to find it in a what should be a top-end mouse from Logitech. What’s even more surprising is that the G303 doesn’t have this problem and it really baffles me why the high-end G502 does.

Overall, the build quality of the G502 is good and I was impressed by the fast click rates I could achieve via the left and right buttons, however the lift-off problem on the left and right click buttons can be a deal breaker for those that lift off their mouse regularly (for example FPS gamers like myself who tap to shoot and move the mouse left to right rapidly)



The design of the G502 is a massive improvement in terms of ergonomics over the G303, however some other design elements have been  missed out by Logitech.

Logitech G502 Mouse - In-hand size

Logitech G502 Mouse - G303 comparison

First of all the ergonomics of the G502 is a pleasant experience over the G303. With my hands (around 17-19cm) that really meant using the G303 was only possible via claw grip. With the G502, my grip is much more natural and feels a lot more comfortable. To me this was the biggest complaint of the G303, which was really designed for people who have claw grip and/or small hands. For the average male user the G502’s ergonomics works a lot better and is more comfortable to use.

The full specification for the G502 are below:
Height: 132 mm (5.2 in)
Width: 75 mm (2.95 in)
Depth: 40mm (1.57 in)

Logitech G502 Mouse - Buttons

To add to the ergonomics the G502 has a fantastic button arrangement which is not only useful for gaming but also media usage. I personally use the mouse with two separate profiles, where with the G303 it was more of a pain to do so as it had a limited amount of buttons, meaning with the G303 I had to go via the software which was annoying. With the G502 there is a total of 9 buttons (including the standard 3 buttons) you can customise which is truly fantastic!
The buttons are really well placed and are comfortable to use – meaning an immersive gaming experience is possible as the provided shortcuts on the mouse allow you to play more efficiently. As said above, the profile switch button can be customised on any of these 9 buttons and switching profiles is immediate via the mouse itself, meaning you don’t have to re-visit the software.

Logitech G502 Mouse - Scroll wheel button

Adding to the ergonomics and the use of the mouse, the scroll wheel has the option to be used in either the standard clicky nature or the “infinite” scrolling, which was something I absolutely loved back on the Logitech MX Revolution over 4 years ago. The scroll wheel can be changed via the 10th button found next to the scroll wheel at the top of the mouse – where a simple click of the button releases/locks the scroll wheel.
The infinite scrolling allows you to quickly and smoothly scroll through web pages, which provides an excellent media viewing experience. It could also be used in games, but I can’t think of when it would realistically be used.

Logitech G502 Mouse - G303 comparison


Moving on from the buttons and the ergonomics to the looks, more specifically the lighting system of the mouse. Unlike the G303 which can be customised with various different colours, the G502 only has a blue colour Logitech “G” logo and DPI/profile lights – which can be customised via the software in terms of its breathing, or for them being completely disabled. What I really dislike is the fact that the lighting system is coupled with the whole mouse, rather than each specific profile. In other words, I would like Profile 2, my media profile to be assigned with a pulsating Logitech “G” Logo, where as with Profile 1, my gaming profile I would like the lights to be completely off – the reasoning behind this, just as it is with the G303 is because I found the lights to be quite hot after a certain amount of time. This means with longer gaming sessions, I felt the warmth of the lights on my palm, which meant I was uncomfortable with them on. Due to this, I have to have the lights always disabled, which is a shame as a simple software tweak would sort out the issue.

Finally, just like with the G303, the mouse is designed for right-handers and not left-handers. With the G502 it’s even more the case as the ergonomics mean it would be impossible for a left-hander to realistically use the mouse.

Overall the design was very good, but not perfect – which is a shame as the only thing I felt was missing was a software update and a more customisable light.



This section will remain unchanged from the G303 review – as the performance was identical due to them sharing the exact same sensor inside.

For me this was the most interesting part of the mouse – I had read that the sensor inside, the Pixart PMW 3366DM sensor is regarded as one of the best mice out there, for various reasons – the main one being due to the close-to-null acceleration it has. Making the G303 and its brother the G502 which share the same sensor, one of the most accurate sensors on the market today. An impressive title to have, especially coming from mice enthusiasts, that test the mice to death.

As I am no professional mouse tester or one that will be able to go into a lot of technical details about the sensor, I would just like to share my personal experiences and how I felt it compares to other sensors I’ve come across.

Logitech G502 Mouse - G303 comparison

The Logitech G303 & G502, to me, felt like the best mouse I’ve ever used. It not only helped my tracking to be perfect, but also really improved my responsiveness as I could, for the first time ever, fully disable all types of mouse acceleration, both in-games and in Windows. Something I’ve always wanted to do, but never truly been able to, due to the mice I’ve had. The DeathAdder was the closest mouse that made me want to switch off all acceleration, but lacked that little bit of tracking that the G303 & G502 possesses.

Logitech G303 Mouse - Windows Acceleration

Just to re-iterate what I’m trying to say above, the mouse’s performance is excellent, the tracking from left to right (with quick swipes) and the tracking on a lot of surfaces is excellent. The Logitech G303 & G502 also hold over 12,000 DPI for you to use, but I personally use it at 1,450 with a sensitivity of around 40% in Windows and in CSGO of 0.6. To me that’s more than enough and a lot of pro gamers even play at 400-600 DPI as they don’t really need more from their mice. This is all subjective, and I even know a friend who uses his mouse on a ridiculously high DPI – so 12,000 DPI is there for you to play with.

Overall, if it isn’t obvious already, the mouse’s performance, like the G303 is sensational – and I would highly suggest for every one to try a mouse of its calibre. Once I tried the G303 and now the G502, other mice feel sluggish or inaccurate.



The software that’s bundled with the G502 is the Logitech Gaming software, which works alongside other Logitech Gaming products, such as my Logitech G710+ mechanical keyboard and the G303. The software is excellent from top to bottom and does everything you would want it to – from changing the behaviour of the LEDs to assigning custom macros per button. What’s even better about the software is that it changes the settings of your mouse in real-time, without you having to hit save or anything, which is something really intuitive in comparison to its competitors’ software. I am running on Windows 10 64-bit too, and didn’t experience any sorts of problems when using the software with my operating system.

As mentioned before, I would have liked the software to be better constructed per profile for the illuminations found on the mouse. It’s something that Logitech could have easily implemented, where profiles would be assigned separate lighting patterns, rather than the lighting pattern to be assigned to the whole mouse, no matter what profile you’re on.

As with my G303 review, I would have liked to have been able to right click on the taskbar icon found in Windows to switch profiles quickly.

Logitech G303 Mouse - Taskbar

Finally one thing that really stood out to me was the lack of cohesion between the on-board memory and the automatic game detection (AGD) mode. In the AGD mode, I could set a macro for CSGO via a keystroke, where I could assign how it would behave and repeat (as you’ll be able to see from the screenshot). However with the on-board memory, I am unable to get this option and on top of that I am presented with a lot less options. Again a simple software update would solve this – some might say, just use the AGD mode, but then I am unable to use the G9 key (at the top of the mouse) to switch profiles! It’s something that Logitech haven’t thought about and it’s lazy for them to have overlooked this.

Overall the software works well and represents the mouse well, but could have been a little more refined.



Overall, the Logitech G502 is a fantastic mouse, mainly due to the Pixart PMW 3366DM sensor that’s found inside it. Yet again, the G502 isn’t a perfect mouse like its brother the G303 which had its issues, but I feel the G502 is a better rounded mouse for those looking for a flawless sensor with better ergonomics. The minor points I made against the G502 are mainly software related and aesthetics – other than that, the G502 is a sensational mouse and one that I would highly recommend.

Logitech G502 Mouse - Top view

I would say if you have small hands get the G303, and if you have normal/bigger hands then go for the G502 – I promise you it’s a decision you won’t regret. I’m very much happy with the G502 and will now use it over the awkward-ergonomics G303 when gaming and for media usage.

As a final note, the price difference between the G303 and G502 is a little baffling. The G502 offers so much more over the G303 and only costs £5 more – which to me makes the G502 an even better buy over the G303.

Hope you enjoyed my review!

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