All Macs In-Depth Tests
The Performance Edge: iMac vs 800 MHz Tower - Which Machine Gives You More Bang For The Buck, A Performance Report

Friday, April 12, 2002

The G4 iMac and the Power Mac G4/800 are very similar in some ways. They both have the same processor, running at the same speed and they both lack a L3 backside cache. So in raw processing power they should weigh in about the same. They do in some of our tests below, where only raw processing power is called for. However in many of the tests we ran, that are also processor focused, the iMac ran about 10-15% behind the Power Mac Tower. What is the reason for this? We believe that it is the slower System bus on the iMac that is, for the most part, responsible for the performance gap between the two machine. The iMac has a System bus running at 100 MHz and on the Power Mac the System bus runs at 133 MHz.

The Tower machine is, of course, much more upgradable than the iMac. You can add multiple drives to the machine, PCI cards and more RAM to them. However if you don't need these things, the new iMac will turn in close to the same performance as the low-end Tower, and will take up a lot less spaces in your work area.

Which Mac would you buy? Let us know why

Difference and similarities in processor and memory & graphics systems of each machine

 
  iMac G4/800 Power Mac G4/800

Additional Resources

Check prices at:

 

Processors G4/800 G4/800
L2 Cache 256k @ 800 MHz 256k @ 800 MHz
L3 Cache None None
Memory 768 MB PC 133 768 MB PC 133
Graphics Card NVIDIA GeForce2 MX with 32 MB of DDR RAM in a 2x AGP slot ATI RADEON 7500 with 32MB DDR SDRAM in 4x AGP slot
Drive 60GB Ultra ATA 40 GB Ultra ATA @ 7200 rpm
Operating System 10.1.2 10.1.2
Price $1,899 $1,599


"Real World" Tests

The tests below are from our suite of real world application tests. These tests feature a diverse selection of applications commonly used by the Mac community. The test suite was designed to render an accurate and well rounded picture of a machine's performance. All of the tests below, except for the game tests, were timed with a stopwatch. The times were then converted to percentages, relative to the Power Mac G4/800, which is set to 100%. For all scores, higher numbers are better.


Desktop Tests

Actual time: Power Mac G4/800 : 44.02 sec .... iMac G4/800: 48.13 sec

Pretty evenly matched. The slightly slower iMac is probably due to slower drive performance

Actual time: Power Mac G4/800 : 32.14 sec Processor usage: 80% .... iMac G4/800: 41.24 sec Processor usage: 75%

Better processor usage in the Power Mac may indicated that the drive is not getting data to the iMac's processor as fast or perhaps the iMac's slower System bus (100 MHz as opposed to 133 on the Power Mac), and the faster RAM on the Power Mac are factors

Actual time: Power Mac G4/800 : 12.15 sec Processor usage: 40% .... iMac G4/800: 20.25 sec Processor usage: 35%

Actual time: Power Mac G4/800 : 9.91 sec Processor usage: 20% .... iMac G4/800: 10.71 sec Processor usage: 20%

The first drive test above stresses different, and more intensive, drive activity than the second. The Folder test has a little over 1,000 files in it, of various sizes. You can see by the processor usage numbers, that the Folder test takes up more of the processor's computational capability



Actual time: Power Mac G4/800 : 80.84 sec Processor usage: 15% .... iMac G4/800: 120.15 sec Processor usage: 15%

This is basically SuperDrive (iMac) vs the Power Mac's solo CD-RW drive. Since the SuperDrive burns at a rate of 8X, and the Power Mac's CD-RW drive burns at 3 times that rate, the results above are no surprise

Actual time: Power Mac G4/800 : 47.39 sec Processor usage: 100% .... iMac G4/800: 52.79 sec Processor usage: 100%

The test above creates and destroys 1,000 windows. See the Let1kWindowsBloom site for more info. The iMac has the NVIDIA GeForce2 MX with 32 MB of DDR RAM in a 2x AGP slot, and the Power Mac the ATI RADEON 7500 with 32MB DDR SDRAM in 4x AGP slot

Actual time: Power Mac G4/800 : 21.68 sec Processor usage: 50% .... iMac G4/800: 26.09 sec Processor usage: 50%

Large document is scrolled from one end to the other using Classic OS 9.2.2 when booted in OS 10.


Large Document & Database Type Tests

Actual time: Power Mac G4/800 : 106.54 sec , Processor usage: 100% .... iMac G4/800: 116.91 sec Processor usage: 100%

A Macro (series of complex actions) was run in Microsoft's Word program, which is part of Office X

Actual time: Power Mac G4/800 : 71.07 sec , Processor usage: 100%. .... iMac G4/800:78.93 sec Processor usage: 100%

A Macro (series of complex actions) was run in Microsoft's Excel program, which is part of Office X

Actual time: Power Mac G4/800 : 29.14 sec , Processor usage: 100% .... iMac G4/800: 33.63 sec Processor usage: 100%

This test takes place in a large AppleWorks document.

Actual time: Power Mac G4/800 : 64.43 sec Processor usage: 95% .... iMac G4/800: 67.56 sec Processor usage: 95%

Large folder is indexed by Apple's search application


Number Crunching & Rendering Tests

Actual time: Power Mac G4/800 : 206.03 sec Processor usage: 100% .... iMac G4/800: 234.16 sec Processor usage: 100%

A Ripple Effect is applied to an iMovie

Actual time: Power Mac G4/800 : 66.55 sec Processor usage: 100% .... iMac G4/800: 67.09 sec Processor usage: 100%

The Fractal program has been highly tuned to take advantage of the G4 and is precisely the type of work that the G4 was made for. It will also gobble up whatever processing capability is present. This is a good test for assessing the fundamental processing power of each machine


Encoding/Decoding Tests

Actual time: Power Mac G4/800 : 248.64 sec Processor usage: 100% .... iMac G4/800: 272.76 sec Processor usage: 100%

A Sorenson encode compresses a QuickTime movie for streaming on the Web

Actual time: Power Mac G4/800 : 172.27 sec Processor usage: 100% .... iMac G4/800: 173.94 sec Processor usage: 100%

Converting QuickTime movies to DV allows you to import them into iMovie

Actual time: Power Mac G4/800 : 132.06 sec Processor usage: 100% .... iMac G4/800: 151.45 sec Processor usage: 100%

The iMac reads CDs at 24X and the Power Mac at 32X

Actual time: Power Mac G4/800 : 12.42 sec Processor usage: 100% .... iMac G4/800: 13.31 sec Processor usage: 100%


Multitasking

Actual time: Power Mac G4/800 : 175.99 sec Processor usage: 100% .... iMac G4/800: 224.14 sec Processor usage: 100%

An MP3 encode, Search & Replace in AppleWorks and Folder Copy are all carried out at the same time

Actual time: Power Mac G4/800 : 516.37 sec Processor usage: 100% .... iMac G4/800: 579.7618 sec Processor usage: 100%

Two Sorenson encodes are performed at the same time


Gaming

Actual fps: Power Mac G4/800 : 18 fps .... iMac G4/800: 14.5 fps

The iMac has the NVIDIA GeForce2 MX with 32 MB of DDR RAM in a 2x AGP slot, cand the Power Mac ATI RADEON 7500 with 32MB DDR SDRAM in 4x AGP slot.. The faster memory system, graphics card slot conspire to put the Power Mac over the top

Actual fps: Power Mac G4/800 : 19 fps .... iMac G4/800: 16.1 fps

The iMac has the NVIDIA GeForce2 MX with 32 MB of DDR RAM in a 2x AGP slot, and the Power Mac the ATI RADEON 7500 with 32MB DDR SDRAM in 4x AGP slot. On the lowest quality setting of Giants you only pick up a couple of frames.