The PowerForce G3 220/110 CPU card contains a IBM or Motorola 220 Mhz PowerPC 750 CPU and 512K of backside cache. This particular card had a IBM CPU. Some people in the industry claim that the IBM CPUs generally can run at higher speeds than the Motorola versions (but the XLR8 266 Mhz card ran at 322 Mhz reliably with a Motorola CPU).

The primary reason for the lower cost of this card is the use of slower, more generic and generally available cache chips. The higher speed rated cache cards use metal cased, expensive IBM 4 or 5 ns (nano-second) access time cache - which is much more expensive than the totally ceramic or plastic construction cache used on the lower cost cards. Like most things computer related, it often costs a lot more to go a little faster.

Components Verified:
To ensure I was not sent a "ringer", I removed the heatsink to check the CPU and cache on the card. The CPU was a 220 Mhz model made by IBM and the cache was made by GSI and rated for 138 Mhz. (click here for proof - a 79K JPG file). Note that since I've publicized that I remove the heatsink for verification, some manufacturers have not sent CPU cards for review - but I'm sure that's just a coincidence.

Workmanship:
As with all recent production G3 cards I've seen, quality of workmanship was very good, with no cold solder joints, no jumper wires, cut traces, or other modifications that would indicate a design change after the pwb was manufactured. (Don't laugh, I've seen these twice on production cards.) The heat sink made good contact with the CPU and thermal compound was used for improved heat transfer.

Observations:
The PowerForce G3 220/110 ran remarkably cool during the tests - even at very high CPU speeds for extended periods of time. The CPU fan in the PowerTower Pro helps I'm sure, but compared to the high speed 604E cards, the G3 CPU cards run much cooler.

Based on my experience running the card far beyond it's rated CPU and cache speeds, I feel it is well designed, and I was impressed with the "headroom" of the PowerPC 750 220 Mhz CPU.

Although I ran most of my tests (including the 291/116 speeds) with the PowerTower Pro motherboard cache dimm installed, that is not a guarantee that your cache will be able to be used, especially if it's a stock Apple 7500-8500 cache dimm. As a general rule, I recommend removing your L2 cache when using any G3 CPU card, based on my experience with most of the models on the market.

Since the Apple G3 systems have far more hardware compatibility issues than the PowerForce card, I do not deduct points for this. There are many other choices of SCSI cards that do work with the PowerForce, including the winner of my SCSI tests - the HammerStorage Jackhammer.

PowerLogix shows this card as compatible with the following Mac models:

• Apple Power Macintosh 7300, 7500, 7600, 8500, 8600, 9500, 9600
  
• Power Computing PowerBase, PowerWave, PowerCurve, PowerCenter, PowerCenter Pro, PowerTower, PowerTower Pro
• UMAX/SuperMac S900, J700.

As with almost all current G3 CPU cards, the PowerForce G3 is compatible with all of Power Computing's cases, including low profile desktop units (via removable support bar used only for Apple systems).

The hardware design was reliable in use at accelerated speeds, allowed great adjustability and was low in cost. For these reason I rated the hardware a 9.

The next page contains a summary and final comments on the product and pricing.