Problems with OS.X

Hi all...

I am having some problems I don't understand with OS.X Snow Leopard (all patches done)...

When I copy files from an external USB drive (exFat or UFS, file system does not seem to matter) to my Mac, I can't do anything else while I do that... the file is not very large, only 8Gb.

When I use bootcamp and Windows7 Pro. 32Bit. I can do the same, while I browse, create RAR archives and copy files between the network and my MAC (under Win7 Pro).
Sure the file takes longer to copy when I do multiple things, but the MAC remains responsive.

I am so disappointed with this problem that I am hesitant to spend any money on Lion as I tested the same on friends Mac who has Lion... guess what... his MAC is also like frozen while the file is being copied.

Anyone else have the same problems? Is it supposed to be that way... to me it seems that the Multitasking on OS.X is not as good as on Windows7.

Any help on possible settings welcome...

If no one knows a solution, I will simply reformat my MAC and allocate most of the HD to Windows7 Pro. as I need to be able to Multitask.

(Oh. I have the same issues on my MAC Mini and MacBook Pro... both also seem to multitask better with Windows7... there must be a setting to improve that under OS.X...)

That has not been my experience with both Macs that I own; 2008 MB and 2011 iMac. I routinely copy large files back and forth between several drives at the same time while I'm writing and replying in these forums. Things do slow down somewhat during the copy but both of my machines remain responsive.