When multiple keys are pressed on my new Logitech k120 USB keyboard, one of the 4 keys pressed does not work. Ctrl+Alt+Del does work though.But on my previous Logitech PS/2 keyboard multiple keypress (Shift,E,↑,↓) worked fine in game. My OS is Win10x64
I have a similar problem on two Logitech k120 keyboards, they are only a few weeks old and have had the problem since new.
It seems to happen only sometimes with combinations including the ctrl key.
I just did a quick test and it seems like I'm hitting the keys too fast - waiting a full second between pressing ctrl and the second key seems to be the only way to guarantee the combination will work (it does work sometimes when typing fast).
I've never had this problem before and I've only every used cheap keyboards, but this one might be a bit too cheap.
The only solutions are to get a better keyboard or type slower.
I use to do
shift + space + w + a + c in a game with Q3 engine (Wolfenstein Enemy Territory). Yepp, it is jumping while crouching in the air (I fly closer to the land and fall down immediately when a bullet hits me, not to mention that I am a smaller target). I am having these K120 keyboards for more than a decade now. The current one might be the 4th of them. Back in 2004-2009 with XP it was fine, I did not have any keyboard issues. After that it was fine for a few years 2009-2013 for Win7, but not for Linux. Now since I bought the current one 1-2 years ago, even dektop applications do not work properly. In game sometimes I got the binding of the
alt key by pressing
shift + space + w + a + c. Sometimes it just forgets one of the keys, for example it does not jump. Desktop apps use to lose focus, so for example I type and suddenly the window loses focus and starts to open the start menu. I guess these keyboards are getting year by year cheaper electronics, or the company wants us to buy more expensive gamer keyboards so they sabotage these keyboards. I don't know what else to buy, because I like the soft button presses of these compared to other keyboards, which hurt my finger joints after a few hours. I really liked these cheap membrane keyboards and I don't want to buy a mechanical for 5x more, because I use to eat by this table too and I use to dismantle the whole keyboard and wash the membrane and the keys from time to time. I don't think you can do anything about this except of buying something more expensive. I am pretty sure it won't be Logitech in my case...
I checked some articles about the n-key rollover. I think in practice 5-6 keys is enough, if you hold the mouse in your other hand while gaming, you cannot press more than 5 keys with your other hand properly, except if you have polydactylism or use your nose too. ;-) The current K120 has less than 6 keys rollover according to this: https://www.mmo-champion.com/threads/1185198-Keyboard-anti-ghosting-(NKRO)-list Prior 2012 it had 5 keys rollover at least. It is still ok for typing, but it is no longer good for gaming. The cheapest alternative with n-key rollover I found is Cougar 200K, it is around 30$ in my country.