processor upgrades Graphics Cards

An Upgrade Card Well Back From The Sharp Blade Of The Cutting Edge: The PowerForce G3/250 Reviewed

Don Engstrom, Reviews Editor

Overview: Yesterday we reviewed the G3/400 PowerForce upgrade card from PowerLogix, before that we reviewed the PowerForce G4/400. Today we take a giant leap back from the cutting edge and look at the PowerForce G3/250.... Now that the laughter has subsided, let me say that while this card certainly is not for all, it will definitely appeal to some. The $175 price tag will appeal to the cost conscious, making this card a good choice for schools looking to upgrade their older machines. In fact, if you look at our Price/Performance chart below, you will see that the G3/250 gives you the best bang for your buck.

Software Installation: PowerLogix provides their drivers on CD and includes an emergency boot floppy as well. Also on the CD is LinuxPPC which may appeal to some but likely not to most. Be sure to install the driver software first as this will enable the backside cache on restart and install important system patches. It is always a good idea to make sure you have the latest version of everything as well. The "G3/G4 Profiler Init" extension configures the card with the settings you have specified and enables the backside cache. The "Cache Profiler" control panel provides the usual array of feedback and control options as well as a few related to LinuxPPC if it is installed.

Hardware Installation: Due to its compact design, handling and installing the card was a little tricky. It was quite a challenge to avoid touching the card's circuitry as there is little unused space on the card. Both Sonnet Tech and XLR8 place extension bars on their cards giving you an easy and safe place to work from. Other that this minor quibble the process was straightforward. The manual includes clear instructions for all of the supported machines. 8 dip switches on the card allows you to adjust the its speed. In a nice touch, PowerLogix pastes a chart of possible dip switch settings on the back of the card for quick reference. The switches are strategically located so they can be reached and adjusted without removing the card from the processor slot. This can be handy if you are trying to overclock the processor. Unfortunately, we were unable to push the card beyond its rated speed. Read on for details.

Performance/Stability: The scores below are right in line with what you would expect when comparing a 250MHz card to a 400MHz one. That is to say you will get a good performance increase over your original machine but not a mind blowing one. The G3/250 also didn't cooperate with my attempts to overclock it. Any setting over the rated 250MHz resulted in a failure to boot. All of the other PowerLogix cards we have recently worked with managed to run over their rated speed. We overclocked the G3/400 up to 440MHz while maintaining a 2:1 (220MHz) backside cache ratio and were able to push the G4/400 to 450MHz. In this latter case we had to reduce the backside cache to from 225MHz to 180MHz (5:2 ratio) in order to achieve stable operation. This, of course, caused a performance hit over the faster 2:1 ratio. While it protested speeds over 250MHz, at 250MHz the card was stable and (with adjusted expectations of course) ran like a champ.

Test Machine Configuration

Our test machine was a 9500 with 96MB RAM and OS 9 installed. We tested with an extension set comprised of all OS extensions plus those installed by PowerLogix. For the MacBench tests virtual memory was turned off and disk cache was set to 512k. These settings are consistent with those used on the MacBench base reference machine, a beige G3/300. For the real world tests we turned virtual memory on and set it to 97MB.

Product: PowerForce G3/250/125/512k
Company: PowerLogix
Rating: (5 possible)
Hits: Brings you G3 performance for under $200, very stable, 3 year warranty.
Misses: Unable or unwilling to run over rated speed, small size and lack of extension bar makes it awkward to install.

MacBench 5.0 Scores

MacBench 5.0 is a subsystem-level benchmark that measures the performance of a Mac's processor, disk, and graphics subsystems to name a few. MacBench normalizes all scores relative to the base machine, a Power Macintosh G3/300. The base machine receives a score of 1000. For all MacBench tests, higher numbers mean better performance. For more detailed information on MacBench click here.




The Price/Performance chart below is based on the MacBench processor scores above and PowerLogix's suggested retail price for each card. For a more comprehensive price/performance chart (based on MacBench 4.0 scores) check out our coverage of the recent price cuts announced by PowerLogix.


"Real World" Tests
(Shorter bars are better)

Time to Scroll a 574 page AppleWorks document from top to bottom.

Using the same document as above we did a search/replace command to replace the word "the" with the word "macbench," over 12,900 occurrences total!

Photoshop 4 "Real World" Test Results

All scores are relative to the stock 9500 which was assigned a score of 100. Lower numbers and shorter bars are better. Bear in mind that we didn't use a "Velocity/AltiVec" plugin for the G4 tests as neither PowerLogix nor Adobe provides one for this version of Photoshop. Adobe, however, has made their AltiVec plugin available for version 5.5.






Render Boy 2.2.0

Time to render "Pool Table" example file

SoundJam MP3 Encode

Time to encode a CD track 4 minutes 26 seconds in length. Scores represent time rounded to the nearest second. SoundJam makes use of the G4's AltiVec instruction set.

Manufacturer -Card


Cooling System

Variable/Fixed Clock Rate

Tech Support


PowerLogix PowerForce G3/250/125/512k PCI Heat Sink Variable Toll Free Phone
3 Years