Why did moving the mouse cursor cause Windows 95 to run more quickly?

Re:Why did moving the mouse cursor cause Windows 95 to run m... by raxxorrax on Wednesday July 03, 2019 @10:36AM (#20344627)

So in today's world... why do so many PCs emit a slight sound when moving the mouse. I know that there are high frequencies involved and periphery is one of the worst perpetrators of electromagnetic interference, but I still find that strange. And what exactly is emitting the sound here?

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by devttyeu on Wednesday July 03, 2019 @10:44AM (#20344690)

Most likely voltage regulotor coils (which live in PSU / GPU or motherboard)

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by blihp on Wednesday July 03, 2019 @11:44AM (#20345295)

Generally it's cheap/poorly designed audio amplifier circuits. Even though modern PC audio is mostly digital, the final stage (getting sound out the speaker) is still analog. If the motherboard designer isn't careful about how they place/isolate/ground the analog audio circuitry, it can pick up some of the PC's stray high frequency noise which gets worse the more you turn up the volume since now the noise gets amplified too.

A work around if you have a motherboard that is particularly bad about this is to use the digital audio output (S/PDIF via an optical or RCA jack) to connect an external amplifier or you could stream it via software. This tends to only be an option if the machine is stationary and not terribly realistic for people with a laptop on the go.

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by shawnz on Wednesday July 03, 2019 @11:52AM (#20345381)

They claim the PC is emitting the sound, not their speakers. So they are likely describing coil whine, not interference.

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by blihp on Wednesday July 03, 2019 @12:35PM (#20345912)

You're assuming a precision in their post that I wasn't (i.e. that it's actually coming from the PCB, rather than 'the collection of parts called a PC sitting in front of me'... which would include the speakers for most people)

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by vageli on Wednesday July 03, 2019 @06:52PM (#20349736)

> You're assuming a precision in their post that I wasn't (i.e. that it's actually coming from the PCB, rather than 'the collection of parts called a PC sitting in front of me'... which would include the speakers for most people)

For what it's worth, this _is_ hacker news. I concede not everyone is tech savvy but I tend to respond to comments as if they are.

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by giobox on Wednesday July 03, 2019 @11:59AM (#20345468)

Could be coil whine? Many modern GPUs are notorious for it.

> https://en.wikipedia.org/wiki/Electromagnetically_excited_ac...

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by Ecolog on Wednesday July 03, 2019 @12:02PM (#20345506)

Similarly I can hear my Kindle buzz when I change page. Electric components can have some coil whine when being pushed

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by _trampeltier on Wednesday July 03, 2019 @11:38AM (#20345236)

When it whas really quiet, I could hear sound from my old cellphone when the screen updatet (Moto G4).

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by jacobush on Wednesday July 03, 2019 @10:37AM (#20344639)

I'd have to guess the CPU - it gets hammered with interrupts and its load changes. But it could be anything really...

[ Parent | on HN ]

Re:Why did moving the mouse cursor cause Windows 95 to run m... by shawnz on Wednesday July 03, 2019 @10:59AM (#20344801)

Don't USB mice use polling rather than interrupts?

[ Parent | on HN ]