[tex-live] previewer xdvi bzw. xdvik

[rewolf]

Hello,
I am using texlive with the OS ubuntu 14.04 on a laptop Acer Aspire E 15 
E5-551G-F1EW with Radeon R7 M265 graphic and have the following problem:
Starting xdvi resp. xdvik the output is generated extremely slow so you 
can read word by word when it appears in the window. In former 
installations even on less fast machines the output appears at once. 
Beside I have the warning:
Cannot convert string "-*-helvetica-medium-r-*-*-12-*-*-*-*-*-*" to type 
FontStruct.
What is to do to accelerate the output of xdvi?
For a hint I am very grateful.
Sincerely
R. Wolf