FreeBSD and poor ata performance

[fandino]

Kenneth Culver wrote:
>> well, my usage pattern is write a big file and few seconds later read 
>> it. So my tests
>> were valid for the use of the computer.
>>
>> But you have reason, I must provide a more formal report. I redid all 
>> test
>> with bonnie++ and results shows Linux (56848 K/sec) two times faster than
>> FreeBSD (26347 K/sec)
>>
>> Any help will be appreciated!
>>
>>
>> Linux test  (slackware 8.1, kernel 2.4.18, ext2 filesystem):
> 
> 
> This test isn't really a fair test either. The ext2 filesystem uses 
> async io,
> and doesn't do any kind of journaling to ensure data integrity in the 
> event of
> a crash. FreeBSD isn't using async, it uses softupdates. Because of this
> FreeBSD SHOULD be slower... but it'll be a lot more reliable than linux 
> in the
> event of a power outage for example. The ext2 filesystem is extremely
> unreliable, and will almost always lose data when there's a crash or power
> outage.

but then why does read/write tests over raw devices performs so bad?
AFAIK on raw devices not filesystem, journaling, caches, etc are involved.