Yes you can upgrade it as for cost here are some prices.
500GB
750GB
1TB
However, I do not know if this is considered a user upgradeable part by Apple, if not then you can potentially void the warranty. Someone else here ought to know. If it is not user upgradeable you can always buy the drive then bring the iMac and Hard Drive to an Apple Authorized Service Center and get the install done by them.
I would also consider an external enclosure for your current hard drive to use for large file transportation and backups.
Firewire 400
Firewire 800
Have fun with your massive new HD.
Some other enclosure alternatives. Check out the customer comments on
Newegg.com and google some online reports -- nothin' but rave reviews:
USB/FW400 enclosure @ $45
USB/FW800 enclosure @ $70
The FW800 model works fine on FW400 -- use a 9-pin to 6-pin cable.
I have one of each; best quality enclosure's I've ever owned or seen,
and the quick-swap drive trays are extremely handy. Assembly is a
snap -- 4 screws and slide it in. No need to open the case, no fiddling
with cables or connectors.
LK
Be warned..it's not necessarily the hardest job I've ever done, but it was definitely not the quickest process upgrading my HDD in a 20inch iMac. I too wanted a 500 instead of 320, all in all I would say I don't regret it, but I know it does void the warranty.
Yes, the HD is upgradable, and as I have heard, even so is the processor!
BUT -- the process of upgrading the iMac HD is a bitch. Basically the only easy "user-upgradable" thing in the iMac is the RAM, which is accessible via the lower panel, and a small Torx 1/6 size driver.
The MacBook Pro HD upgrade is also a bitch. The only "easy-install" Macs (as far as HD upgrades) go is the MacBook (regular) and the Mac Pro...and the xserve if you count that. The Mini is hard to get into for upgrading.
The original 1998-2001 style iMacs (CRT display) were pretty easy to upgrade, although the RAM upgrade was a bit tricky. You had to get all the internal cables unhooked, rehooked, and tucked away right. Today's machines (Macs) are designed so that just the items that Apple wants you to be able to upgrade are accessible (for example RAM, HDs, and PCI cards in the Mac Pro). The CPUs on those machines are upgradable as well, but installation is a bit of a mess if you screw up.
But, yes, all of the iMacs have had upgradable drives. If it uses a standard size and it plugs into the board, then you can upgrade it. An iPod touch could not be upgraded, because the Flash memory storage is a part of the chip.
ok, I am tired now.
Do you mean that I get the enclosure for the old HD and use it as external HD?
Either way. Upgrade the internal drive and put the old one in an enclosure,
or leave the internal as-is and put the new drive in the external enclosure.
A new fast internal (any Seagate 7200.11 series or the WD7500AAKS)
would give the best performance, but it's more work. I'd stay away from
Hitachi internals, they tend to run hot -- and the ALU iMacs are hot already.
LK