I changed my computer recently, and the very same program using Python and Pyglet runs a lot slower on the newer computer than on the old one (25 seconds vs. 10 seconds).
The older was an Asus EEE 1015p, with the following specs :

processor : Intel Atom N570
memory : 2 Gb
gfx : Intel GMA 3150
OS : Windows 7 Starter Edition 32
python version : 2.7
pyglet version : 1.1.4

The newer is a HP Pavilion dm1 :

processor : Processeur   AMD E2-1800 APU with Radeon(tm) HD Graphics, 1700 MHz
gfx : AMD Radeon HD 7340 Graphics
memory : 4 Gb
OS : Windows 8 64
python version : 2.7 (32 bits)
pyglet version : 1.2alpha1

I suspected a problem of graphics driver, but some programs using OpenGL (for example, Playstation2 Emulator PCSX2) run clearly faster on the newer (by around 40 %) so I'm quite surprised. So I wonder if speed issues are known for some pyglet versions.
The program use batches to render a map made of 4 tiled layers, on which sprites are moving.
Thanks to anyone who can point me what is wrong...
Problem solved. I give the answer in the unlikely case someone would encounter it :
it was a driver settings issue : in AMD Vision Engine Control Center, I had to move performance vs. quality setting to max. performance. I have now similar performances on the 2 machines.
Pyglet slower on a faster computer