Is it faster to install windows with an USB rather than with a CD?

Solution
DVD transfer rate is about 20 Megabytes per second (MB/s). USB 2 can peak around 60 MB/s. Although realistically it seems to rarely go above 30 - 40 MB/s. USB 3 is 640 MB/s. Usb 3.1 is 1250 MB/s.

So even low end USB 2 thumb drives is notably faster than a DVD when reading data.
DVD transfer rate is about 20 Megabytes per second (MB/s). USB 2 can peak around 60 MB/s. Although realistically it seems to rarely go above 30 - 40 MB/s. USB 3 is 640 MB/s. Usb 3.1 is 1250 MB/s.

So even low end USB 2 thumb drives is notably faster than a DVD when reading data.
 
Solution
It depends on the speed of your usb media device and the protocol it uses, usb3 devices will be the fastest, but depending on the device your speed will wildly very (20MB/s - 300MB/s).

Here is a slightly dated USB 3.0 flash drive comparison chart to give you a better idea:
http://www.tomshardware.com/reviews/usb-3.0-thumb-drive-review,3477-2.html

Due to seeking, DVD/CD installs will most likely remain the slowest of the media you mentioned.

I use my USB3.0 SanDisk Extreme 16GB to install OS's with, and it rips through the install very very quickly. It has read speeds around 250MB/s last time I checked.
 


Thanks and @brandonYoung as well
 
They sure don't, but it helps if you have an old one lying around. If you want to install Windows 7, you won't be able to use USB3.0. I have both USB2 and USB3 sticks and Windows 7 doesn't install on my friend's PC with either one. Mine, it installed with 2.0.

If you have an optical drive and a DVD, you won't need to worry about this problem at all.

You may think this post is irrelevant since 7 is now old, but that's the case if you want to install it.