Net Neutrality...

Owen DeLong owen at
Fri Jul 18 22:48:48 UTC 2014

On Jul 18, 2014, at 11:35 , William Herrin <bill at> wrote:

> On Fri, Jul 18, 2014 at 2:05 PM, Rob Seastrom <rs at> wrote:
>> Michael Thomas <mike at> writes:
>>> On 7/17/14, 2:15 PM, Valdis.Kletnieks at wrote:
>>>> /me makes popcorn and waits for 4K displays to drop under US$1K and
>>>> watch the network providers completely lose their shit....
>>> $339!
>>> I use it for doing dev. It's *fabulous*.
>> "Refresh rate is limited to 30Hz with 4K"
>> Bracing for my first seizure ever in 3...  2... 1...
> Hi Rob,
> An LED screen doesn't refresh the way a CRT does, right? The light
> doesn't flash and fade, it stays constant until the next change. So
> why would a 30 hz refresh rate make any difference at all for tasks
> which update the screen less often than 30 times a second? Mike did
> say he used it for doing software development.

Well... Yes and no.

An LED screen doesn't refresh the way a CRT does, that part is true.

However, the brightness of any particular color of any particular pixel in any LED
screen is usually controlled by a process known as Pulse Width Modulation (PWM)
where the LED actually turns on and off several thousand times per second and
modifications of the ratio between the on-time and off-time in those cycles are
used to control the apparent brightness. As such, the LEDs are actually turning on
and off (flickering) much much faster than any CRT would, but it's not the same
kind of flicker.

However, most "LED Screens" aren't actually LED screens, most of them are
LED backlit CRT Screens. (I didn't look at the specs on this one in detail, so
I don't actually know which type it is).

This gets further complicated by technologies such as selective dimming, etc.


More information about the NANOG mailing list