Why bios(generic) is slow?

Hi

Can you tell me why generic bios is so slow compared to linuxbios. 
In other word, why linuxbios is fast? 
I think "do little thing" is not enough to explain x10 time difference. 
What does bios do other than linuxbios does and where it spend so much
time?

Regard, 
Heechul

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HeeChul Yun,          
Embedded S/W Team at ETRI
phone: [phone]