All Macs In-Depth Tests
The Performance Edge: G4 vs G3, 733 MHz vs 700 MHz, Power Mac vs iMac - A Performance Report
Monday, November 12, 2001

We have received numerous requests to compare the performance of the new iMacs to the Quicksilver towers. Below we take a first stab at this, comparing the top of the line iMac (700 MHz), to the bottom of the line QuickSilver Power Mac (733 MHz). Though vastly different machines, they do have one thing in common. Neither one has a L3 high-speed backside cache memory. Instead they have an on-chip L2 cache of 256K that runs at full processor speed. This is great for small documents and most finder operations, but can be a disadvantage when working with large documents, spreadsheets and databases. None of the current iMacs, have a L3 cache. However the two top QuickSilver Power Macs have, not only the on-chip L2 cache, but also 2 MB of L3 Backside Cache (in the case of the dual-processor machine 2 MB for each processor).

So the processor & memory sub-systems of both the machines compared below are structurally similar, although the Power Mac has a somewhat faster System Bus.

What are the differences from a performance standpoint? Well the iMac has the older G3 processor and the Power Mac has the G4 with, what Apple calls, the Velocity Engine (AltiVec). As you'll see from the benchmark results below, the Velocity Engine can make a lot of difference when running processor intensive applications that can take advantage of it.

The other major performance difference is that the Power Mac has a better graphics card with twice the graphics memory. You will see that play out when running computer games, scrolling in applications and in over-all snappiness of desktop graphics.

And without further ado ..... the results

iMac Buyer's Guide ......... Power Mac Buyer's Guide

"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 (with the exception of the Quake III & CineBench 2000 tests) were timed with a stopwatch. The times were then converted to percentages relative to the Power Mac G4/733, which is set to 100%. For all scores, higher numbers are better.

Finder Tests

 

Pretty similar scores here on hard drive performance. Difference can be largely attributed to the slightly higher clock speed of the Power Mac

AppleWorks 6 Tests

Better performance of the Power Mac is largely due to the faster graphics card, though faster processor speed may also be a slight factor

Again the faster processor speed is the factor here

Quake III Tests
These scores are relative.

At 'fastest' setting the processor plays a bigger role, though graphics card is a factor also

Most, if not all, of the processing is taking place in the graphics card

Photoshop 6 & Other Data Crunching Tests

 

The Photoshop filters used for this test respond well to the "Velocity Engine" of the G4, hence the better score

Interestingly when running Photoshop filters that are not AltiVec savvy, the G3 is apparently slightly faster than the G4

This is pure, raw data crunching. Program does not utilize Velocity Engine.

Again the G3 is slightly ahead of the G4 for this processor intensive task

This is a combination of both processor and graphics card performance

Encoding/Decoding Tests

Heavy duty crunching going on here. QuickTime 5 responds very well to the G4 processor

... as does iTunes

The CD-RW drive in the iMac burns at 8x and the Power Mac at 12x