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
(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
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
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
And without further ado ..... the results
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.
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
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
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
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