[K12OSN] Thin c850 Neoware low, problem sound and yum

[abegoc at free.fr]

 I have a server K12LTSP and a thin c850 (neoWare).
    1 - The browser surfing is very slow. Can I test the performance of the 
thin client when i am logged in ?
    The test of the server is OK (by top when logged).
    2 - When the thin is booting, i have always : no sound driver loaded. An 
idea ?
    3 -Can i make update of the server by yum . I have several errors from 
yum
    Thank you for your responses.