"Most impressively, the test results for a Mac
upgraded with the PowerLogix Dual 1GHz card are on a par
with Apple's current Dual 1GHz Mac .... The PowerForce
Dual G4 is a great way to give an aging PowerMac a new
lease on life". MacUser, UK, January 2003
The PowerForce Dual G4 Series 100 processor card (and its
cousin, the single
processor version) is the most advanced, highest performance
CPU card available for any PowerMac, and the only one of
its kind for the PowerMac G4. (Click
here to find out which model of PowerMac G4 you have.)
The PowerForce Dual G4 Series 100 has many "firsts" to
its credit. It is still the first and only dual processor
upgrade, and now it's the first to utilize the latest (7457)
The PowerForce Dual G4 was designed along with the single
processor version. In fact, they share the same circuit
board. This kept design costs to a minimum. In addition,
we kept cost low in other ways; for example, L3 cache.
The goal was to deliver performance on par with the latest
Macs at the lowest cost, which is why we didn't blindly
follow Apple with regards to L3 cache. The cards have SDR
cache instead of the more expensive (but quite unnecessary)
DDR cache. This meant the incremental cost could be devoted
to a second processor instead, which provides much greater
performance. (As shown in our recently published L3
Cache White Paper, DDR cache offers zero performance
advantage over SDR cache.)
Paper also shows that a larger L3 cache is best (not
necessarily the speed or the type) and the PowerForce
Dual G4 models have twice as much L3 cache as Apple's
Dual 867 and Dual 1GHz models.
Speaking of DDR cache, it has recently become common knowledge
that the latest PowerMac G4 architecture, in spite of a
faster bus and DDR SDRAM, performs no better than previous
generation models when benchmarked with identical processors.
This is also true when comparing the latest models to a
PowerMac G4 upgraded with a PowerForce Dual G4. Installing
a PowerForce Dual G4 card into an older PowerMac G4 gives
equivalent CPU performance to the 2002 PowerMacs, for significantly
less expense. This preserves the user's investment in existing
There are even more unique design features...
For example, the power supply. The power supply on Dual
G4 Series 100 card can easily provide up to 100 watts...i.e.,
much more than typically needed, but the card was designed
to support the needs of dual processors. It's the same power
supply pioneered on the single
processor PowerForce G4.
A typical Apple power supply runs at 250KHz, single phase.
The PowerForce Dual G4 Series 100 has a three phase power
supply that runs at 1.2MHz, five times faster than Apple's.
This means it can react to the processor's varying power
requirements much more quickly. It's the first three phase
power supply ever used on a Mac processor card.
This means cleaner power, better transient response, lower
heat, and more reliability... especially important with
the PowerPC Apollo at those high speeds. The power supply
is also very small and compact, low profile, with no huge
inductors or other large components taking up space.
The cards will accept faster 7457 processors as they become
Check out the single processor reviews on xlr8yourmac.com and macsales.com.
These upgrades require MacOS 9.2.2*, MacOS X 10.2.8 or
10.3 Panther. Classic in OS X 10.2.8 and 10.3 is fully compatible.
PowerLogix also includes a firmware update so the system
properly recognizes the 7457 processor. This update is required
(but is easily reversible.)
Some early PowerMac G4 'AGP' models have a chipset that
is not compatible with dual processors. For these machines
we recommend the single
processor PowerForce G4. To determine if your AGP is
dual compatible, visit this page.
One note of clarification: if your PowerMac G4 came from
Apple as a dual processor machine, it has a single card
with two processors on it. This dual CPU card is removed
and the PowerForce G4 card replaces the Apple card and *both*
CPUs .It is not possible to install two PowerForce G4 cards
to replace the two processors in your machine; only one
card is required.
*Note: The dual card operates in single CPU mode under
MacOS 9.2.2. For full dual functionality OS X is required.