iMac and eMac Index

Upgrade Guide for Tray-Loading iMacs

Rev. A - Rev. B - Rev. C - Rev. D

Dan Knight - 2003.05.12
Prices updated 2007.08.03

The original iMac was a competent, competitively priced computer, but it was never a barn burner when it came to performance. The tray-loading models came in 233, 266, and 333 MHz versions, shipped with 32 MB of memory, and generally included low-cost, slow 4400 rpm hard drives.

Unlike later models, there were no options for CD-RW or Combo drives; the original iMac design only came with a plain old fashioned 24x CD-ROM drive. Video is built into the system board; there is no way to replace it with a better video processor.

Before investing a lot in upgrades, check our Best G3 iMac Deals to see if you might be better off simply buying a newer iMac that has the features you want.


Even back in 1998, 32 MB was a pretty paltry amount of memory. It is generally possible to install 384 MB total memory in an iMac with a low profile (1.5") 128 MB SO-DIMM on the bottom and a 256 MB one on the top. However, the exact amount a Rev. A-D iMac can handle varies from unit to unit. We have field reports of some models accepting 256 MB modules in both memory sockets and reaching 512 MB - and other reports of early iMacs that won't work at all with 256 MB modules. There appears to be no way to know in advance whether a particular iMac will work with a certain sized memory module.

We recommend no less than 64 MB for Mac OS 8.1, 96 MB for OS 8.6-9.2.2, and 192 MB for OS X. For really good performance, you should have at least 96 MB under OS 8.1, 160 MB under later versions of the classic Mac OS, and all the memory your iMac will support to get the most out of Mac OS X.

We suggest you visit ramseeker for current pricing on the SDRAM SO-DIMMs used in the iMac - and be sure to check with the vendor whether their modules are known to work in the iMac. Even then you may find your iMac is uncooperative, so do your best to assure yourself that you're buying compatible RAM and know the vendor's return policy if it doesn't show up properly in your iMac.

Current RAM prices (Aug. 2007) are 64 MB, $9; 128 MB, $14.99; 256 MB, $32.49. Bear in mind that not all slot-loading iMacs support 256 MB modules.

Hard Drive

The hard drives used in these iMacs were chosen because they were inexpensive. They have very limited capacity and often have sluggish performance (4400 rpm drives were often used to keep Apple's cost down). At the very least they should be replaced with a larger, more modern 5400 rpm drive. If you can swing it, we recommend a 7200 rpm drive with an 8 MB or larger buffer for better performance. (Note that the iMac doesn't support drives over 128 GB without third-party drivers. See a href= "/2005/how-big-hard-drive-imac-emac-power-mac-powerbook-ibook/">How Big a Hard Drive Can I Put in My iMac, eMac, Power Mac, PowerBook, or iBook? for more details.)

This is especially helpful if you run OS X on your iMac, since virtual memory is always enabled. A faster drive can really speed things up.

Beyond CD-ROM

Although you can connect an external CD burner to the iMac using USB, that can be painfully slow. The USB 1.1 specification has a total bandwidth of 12 Mbps but only allows up to 8 Mbps for any device. Because of this, USB CD burners cannot reliably burn at speeds greater than 4x - and that calls for a lot of patience.

An internal CD-RW drive is a much better idea, since it can work at the full bus speed of the IDE bus inside the iMac. We strongly recommend buying a drive especially designed for the iMac, since anything else will be a cosmetic mess and may otherwise be difficult to install inside the iMac's housing.

In terms of features, we urge you to buy a drive with buffer underrun protection, since this greatly minimized the chances of a bad burn ruining your blank CD. Most third-party drives ship with Toast or another third-party disc burning program; some drives also work with the disc burning support of Mac OS 8.6 and later.

Replacement CD-ROM drives

CD-RW drives, listed by maximum write speed

Processor Upgrades

Once you have enough memory and a fast hard drive, you can really unleash your iMac with a processor upgrade. The Sonnet Harmoni include a FireWire port, which can be a real plus for connecting to digital video camcorders or fast external drives. The XLR8 G4/400 is the only G4 upgrade currently made for the tray-loading iMac - and at $99, it's quite a bargain.

G3 Upgrades

  • Harmoni G3/600, Sonnet Technology, $300, includes FireWire
  • Harmoni G3/500, Sonnet Technology, disc., includes FireWire
  • iForce G3/400, PowerLogix, disc.
  • iForce G3/500, PowerLogix, disc.
  • iMAXpowr G3/500, Techno Warehouse, disc.
  • iMAXpowr G3/466, Newer Technology, disc.

G4 Upgrades

  • FastMac G4/466, FastMac, disc.
  • iForce G4/500, PowerLogix, disc.
  • iMAXpowr G4/433, Newer Technology, disc.
  • iMAXpowr G4/466, Techno Warehouse, disc.
  • unknown G4/466, 1 MB cache, $199, Wegener Media, 10 minute installation
  • XLR8 MAChSpeed G4/400, Daystar, $99 factory installed, supports 256 MB modules, 30 minute installation

NOTE: The Sonnet HARMONi card was incompatible with early versions of Mac OS X 10.4. The FireWire port would tie up 100% of CPU resources. This problem was fixed in version 10.4.7 (if not earlier). If you have a HARMONi card that's had this issue, be aware that updating to 10.4.7 or newer should fix it.

Other Improvements

Most users find the original iMac mouse leaves a lot to be desired, and the iMac's keyboard isn't a whole lot better. There are lots of options in USB mice and keyboards. We suggest you go to your nearest Apple retailer and take a look at the current Apple Pro mouse and keyboard as well as the wide array of third-party ones available from Logitech and other companies. (If you like the idea of a wireless setup, we're huge fans of the discontinued Logitech Cordless Elite Duo.)

Go to the iMac index.

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