My Logitech Marathon Mouse has an extremely short range

If the mouse is right next to the laptop/nano receiver (<6 inches away) it works great, but if I put the laptop to the left of an external (wired) keyboard and the mouse to the right (~1.5 feet away), I'm already getting very noticeable mouse lag and cursor jumping.

I know Logitech isn't the company they used to be a decade ago, but have their newer products truly fallen so low? Or is there simply something wrong with my mouse and/or nano receiver?

 

depends on the laptop really, I had the same issues when I had an ASUS laptop before but now not with the MSI

Make sure there aren't any speakers or anything causing interference next to you.

Also try putting the received in a different USB port

 

The problem is unique to your setup. A wireless Logitech marathon mouse should not have such severely hobbled range.

The problem is either a defective product (bad radio and/or antenna in the mouse or USB receiver); or the problem is caused by wireless interference.

You can test for interference by moving your laptop and kb/m setup to a different location, and seeing if the problem persists. If you live in a big enough house/apartment, close all the doors you can in the house. The idea is that if there is another 2.4Ghz radio in your house causing interference, the walls / doors will weaken that signal as much as possible while you do your test.

If you don't live in a large-enough house / apartment, do this test somewhere else. It could be in your car, a friend's place, University library, etc. All you need is laptop, keyboard, mouse.

If that doesn't work, get a replacement for a defective device through either the retailer, or Logitech.

 

Oh. And before you do any of that, do a quick test by putting your laptop in airplane mode. This quickly tests if one of the internal radios used by your laptop is the culprit.

Regardless of the results of this test, still do the other tests I mentioned above. The reason is because even if you find out it's related to interference on the 2.4Ghz spectrum, it may be the router (and not your laptop internal WiFi) causing the problem.