MAIN INDEX of latest speed tests

New iMac G5/2.1
and iMac G5/1.9

Originally posted October 24th, 2005, by rob-ART morgan, mad scientist
Corrections added October 28th, 2005 regarding GPUs and Ethernet

We are receiving a lot of questions regarding the new iMac G5s. We're days away from posting a shootout between the new iMac G5/2.1GHz with X600 XT GPU and the previous iMac G5/2.0GHz with Radeon 9600 GPU. Meanwhile, we've researched the answers to some of your questions.

"Will the 533MHz memory help it go faster?"
Theoretically it should help, but total performance depends on the synchronization of the memory speed with memory bus speed with the frontside bus speed with the CPU clock speed. There are some sophisticated computations you can make to predict the gains but we prefer to do real world tests.

Apple ships the iMac with one 512MB CAS 4 PC2-4200 module. There is one slot for upgrades which means you are limited to single 1GB upgrade module unless you are ready to pay as much as $1200 for a single 2GB stick. It's a shame Apple didn't keep the old configuration of two SDRAM user serviceable slots. Then you could get two 1GB sticks at a fraction of the cost of the one 2GB stick.

"Is the Radeon X600 XT GPU any faster than the previous model's Radeon 9600?" (Correction) These are not mobility GPUs as I first thought. The Radeon X600 XT, as I've been told, has a 53% faster core clock speed and fill rate while the core memory speed is 85% faster than the previous model's Radeon 9600. So when running OpenGL intensive apps (like Motion, iMaginator, Doom 3, etc.), it should do much better.

One of the liabilities of the iMac G5 is that you are stuck with whatever GPU you get. It is not upgradeable. At least with the Power Macs, you can choose your graphics card and replace it with a faster one later or add a second one. Oh and it still can't do dual displays -- only mirroring with an external display.

"Is the problem with overheating drives been fixed in the new iMac G5?"
It appears to me that it has been addressed. The back cover has been redesigned to be thin at the edgs and bulges out at the center (see graphic below). The previous model was thicker on the edges and flat all the way across. Whether that change aids in airflow from bottom vents to the top slot is speculation on our part. The fact that the ports have been moved from the side to the bottom indicates some level of redesign of the main logic board. I was able to run Temperature Monitor on the new iMac G5/1.9GHz while making repeated runs of QuickBench disk "basher." The drive never rose above 49 degrees C, which is safely below the 55C max specified by drive manufacturers..

I have sampled temperatures on several of the previous model of iMac G5. They were all running above 60C even when at idle.

"What other performance improvements should I know about?"
(Correction) I said earlier that this new model features Gigabit Ethernet (1000BaseT). That feature was added back in the May 2005 revision. It won't help you run faster on the Internet via your cable, DSL or satellite modem, but if you are connected to a gigabit network, you can transfer files to/from the local network servers faster. You can also connect a CAT 6 crossover cable to another Mac with Gigabit Ethernet port and transfer files rapidly.

I wish the iMac had at least one FireWire 800 port (like the Power Mac and PowerBook). I would gladly trade the gigabit ethernet port for a FireWire 800 (or Serial ATA) port.

"Where are the performance graphs?"
We are as anxious to test these new iMac G5s as you are to see the results. We are working on a shootout between the previous iMac G5/2.0 and the new iMac G5/2.1.

If you get one if the new iMac G5s before we do, feel free to email , the chief mad scientist. We want you want to run some tests for us.


When ordering products from Apple Store USA, please click THIS TEXT LINK or any Apple display ad as your "portal" to the online store. In so doing, you help to support Bare Feats. (DON'T LIVE in the USA? See links for Apple online stores in other countries.)

For refurbished, reconditioned, open box (as well as new) iMacs, check with Small Dog and Power Max. Also look for the "SPECIAL DEALS" link on Apple's online store.

Has Bare Feats helped you? How about helping Bare Feats?

2005 Rob Art Morgan
"BARE facts on Macintosh speed FEATS"
Email , the webmaster and mad scientist