xdvi takes a long time to refresh
 

This is
CentOS 7 3.10.0-957.21.3.el7.x86_64

xdvik version 22.86 (Xaw toolkit)
Libraries: kpathsea version 6.1.1, freetype version 2.8.0

It is rather unfortunate that scrolling a .dvi file generated by
latex will hang at some point.

It is certain to happen. When it happens, i can do two things:

1. Wait, then after many seconds, it will move to a few pages down the road
since i have hit a few Enter strokes, which is not what I want.

OR

2. Click on the mouse, and the screen is refreshed immediately. The page
will go down a few pages down too.


I have used xdvi in many Linux (CentOS 6) and never have
such observation. On one older machine
with identical CentOS 7 setup, it is strange since fast scrolling is observed too.

So question: What goes wrong? How can I start to pinpoint the bottleneck?

Graphics card + Xorg (bad drivers?), slow hard disk (seems unlikely
since I have CentOS 6 on the same machine but no such
delay) I have not got a clue what can
cause this to happen.

In my experience
xdvi scrolls really fast even for a large document -- a main reason
I used it a lot. I do not know
why that combinations of OS and xdvi mentioned at the top is not
behaving properly.

graphic card seems okay..

Check on the installed Linux Mint 18 and Debian 9 on the SAME machine and the xdvi there are very
healthy!

Is this one of the Fedora/CentOS7 jokes on me?

but unsolved too.

Out of my 3 computers installed with CentOS 7, 2 have this problem..

I suspect the faster computers will have this problem since it reacts faster to holding the Enter keys and got utterly confused very soon. Anyway,
the problem is not fatal, but it is good to know the cause of it.

I suspect graphic card driver.
Then I do this:

Now the scrolling is good!

It is very strange that direct rendering is YES, in contrast to post 1. (In fact
only I realize that direct rendering was not okay in post 1. I always
thought the kmod-nvidia has made everything okay)