Screen Latency Through the Ages: Computers Have Gotten Slower Since the Apple IIe

Man touching a screen labeled

Computers have gotten faster when it comes to computations—CPUs are astronomically more powerful today than they were in the early days of personal computing. Thanks to some painstaking tests by engineer and super nerd* Dan Luu, we now know of one area where computers have gotten slower: “the latency between a keypress and the display of a character in a terminal.”

Which is interesting.

Man touching a screen labeled

In a blog post (via Gizmodo), Mr. Luu detailed his findings after months of testing every device he could get his hands on. Using two high-speed cameras, Mr. Luu tested how long it took for a character to appear on the display after after he pressed the key on the keyboard (virtual or real).

In the table below, you’ll see Apple’s venerable Apple //e—a device that was released in 1983—is the fastest of the 22 computers he tested. It took 30 milliseconds on the //e. Compare that to the 200 milliseconds it took on the PowerSpec G405 running Windows 10—a device released in 2017.

Dan Luu’s Latency Test Results

computer latency
year clock # T
apple 2e 30 1983 1 MHz 3.5k
ti 99/4a 40 1981 3 MHz 8k
custom haswell-e 165Hz 50 2014 3.5 GHz 2G
commodore pet 4016 60 1977 1 MHz 3.5k
sgi indy 60 1993 .1 GHz 1.2M
custom haswell-e 120Hz 60 2014 3.5 GHz 2G
thinkpad 13 chromeos 70 2017 2.3 GHz 1G
imac g4 os 9 70 2002 .8 GHz 11M
custom haswell-e 60Hz 80 2014 3.5 GHz 2G
mac color classic 90 1993 16 MHz 273k
powerspec g405 linux 60Hz 90 2017 4.2 GHz 2G
macbook pro 2014 100 2014 2.6 GHz 700M
thinkpad 13 linux chroot 100 2017 2.3 GHz 1G
lenovo x1 carbon 4g linux 110 2016 2.6 GHz 1G
imac g4 os x 120 2002 .8 GHz 11M
custom haswell-e 24Hz 140 2014 3.5 GHz 2G
lenovo x1 carbon 4g win 150 2016 2.6 GHz 1G
next cube 150 1988 25 MHz 1.2M
powerspec g405 linux 170 2017 4.2 GHz 2G
packet around the world 190
powerspec g405 win 200 2017 4.2 GHz 2G
symbolics 3620 300 1986 5 MHz 390k


There’s a reason for this, as Mr. Luu details on his wonderful blog: it takes more steps to get the character from keypress to screen now than it used to take. This especially true for operating systems designed to run on wide arrays of hardware.

Those extra steps are part and parcel of the many more things modern devices can do, however, and the reality is that few of us notice this lag.

Scroll Latency on Mobile Devices

Dan Luu also put together a table of scroll latency on just mobile devices and found that Apple’s hardware is the fastest in the land. Apple iPhones and iPads were had 8 of the top nine spots for screen latency, including the first 7. In fact, an iPad Pro 10.5-inch using Apple Pencil had the same screen latency as that old Apple //e, at 30 milliseconds. Second on the list, at 70 milliseconds, was iPad Pro 10.5-inches without an Apple Pencil.

The Google Pixel 2L—Google’s flagship smartphone? 110 milliseconds and tied for 12th. Coming in last on the list was the Kindle 4 at a staggering 860 milliseconds. Here’s the chart in full:

Dan Luu’s Chart of Scroll Latency on Mobile Devices

device latency
ipad pro 10.5″ pencil 30 2017
ipad pro 10.5″ 70 2017
iphone 4s 70 2011
iphone 6s 70 2015
iphone 3gs 70 2009
iphone x 80 2017
iphone 7 80 2017
iphone 6 80 2014
gameboy color 80 1998
iphone 5 90 2012
blackberry q10 100 2013
huawei honor 8 110 2016
google pixel 2 xl 110 2017
galaxy s7 120 2016
galaxy note 3 120 2016
moto x 120 2013
nexus 5x 120 2015
oneplus 3t 130 2016
blackberry key one 130 2017
moto e (2g) 140 2015
moto g4 play 140 2017
moto g4 plus 140 2016
google pixel 140 2016
samsung galaxy avant 150 2014
asus zenfone3 max 150 2016
sony xperia z5 compact 150 2015
htc one m4 160 2013
galaxy s4 mini 170 2013
lg k4 180 2016
packet 190
htc rezound 240 2011
palm pilot 1000 490 1996
kindle paperwhite 3 630 2015
kindle 4 860 2011

I find all of this fascinating, and it’s a great reminder of two things: the first is that complexity can have a deleterious effect on speed. The second is that Apple’s mobile devices are way better than everyone else’s.


2 thoughts on “Screen Latency Through the Ages: Computers Have Gotten Slower Since the Apple IIe

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.

WIN an iPhone 15 Pro Max!

Enter our epic giveaway for a chance to win the latest iPhone 15 Pro Max!