I have the same problem with any mac that has 10.6. On macs that I can go back to 10.5 on they work fine and fast. I install a used system at a client and that CPU is new enough to not be able to revert to 10.5 and their NAS is so slow that it is unless. So it's Apple's problem, they broke the protocol for NAS in 10.6 and will not fix it. My clients don't want to make the Move to 10.7 at this time,I am not eve sure if NAS will work well with 10.7 and I think Apple has to rethink its policy of forces us to upgrade to the lastest OS to get their problems fixed. Fix 10.6 to NAS protocol.
Maybe we don't need major system upgrades every year.. Fix the current system before you give us more problems with a major OS upgrade.
Now I might sound tainted, but I have been an Apple person since the first, Apple II came to market.. I sold many of them. So lets not go back to Apple 1980's when they couldn't get anything right.. They may be all powerful, now but they need to remember when there were rumors of them being sold and the stock sold for $11.00 a share.
I have searched for a fix, and many forums have stated the problem, but I just can't figure why they haven't relized that Apple mess up the protocol in 10.6. Its simple, everything works fine on 10.5 they forced us to upgrade to 10.6 and it's broke. go back to 10.5 and it's fixed. So logic states that Apple's 10.6 is different when it comes to NAS protocols... Simple... Fix go back to 10.5 Real fix.. Apple needs to fix it with a patch to 10.6
I have no problems with someone proving me wrong that it works fine, in 10.5 and is broken, very slow in 10.6..