SPI vs low level functions.

Hi,
I am trying to determine if there is a difference in
I/O cost between SPI functions and low level functions
like heap_fetch, heap_getnext, etc...
I want to decide if there is any merit for using the low
level functions instead of the easier SPI.
My guess is that they both use the same underlying framework
for reading and caching blocks but I can't be sure.

Also, is there any significant CPU cost between them?
10x.


Regards,
	tzahi.

WARNING TO SPAMMERS:  see at
http://members.lycos.co.uk/my2nis/spamwarning.html