processor upgrades Graphics Cards

Plenty of Power in a Small Package PowerForce G4/350 and G4/400 Cards Reviewed

Don Engstrom, Reviews Editor

General Impressions: Two things stuck me as I looked over the two cards from PowerLogix. They are amazingly small, just long enough to fit in the processor slot, and they sport a fan on top of a rather small heat sink. We haven't seen a fan in use since the untimely demise of the Vimage line of upgrade cards.


Software Installation:PowerLogix provides drivers on a floppy which also serves as an emergency boot disk. More on this later. Be sure to install the 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 as well. The installer places two extensions in your system folder. The "G3/G4 Profiler Init" configures the card with the settings you have specified and the "AltiVec enabler" makes the system aware of the AltiVec (Velocity) instruction set on the G4 processor. To see a performance gain you will still need to be running applications that are written specifically to take advantage of AltiVec. The last item installed is the "G3/G4 Cache Profiler" which allows you to adjust the speed of the backside cache and make a variety of other advanced settings. The cache profiler also lets you disable speculative addressing. Speculative addressing, also called speculative processing has been the subject of heated online debate after Newer Technologies released a "white paper" warning of data corruption, boot problems etc. if speculative addressing is not dealt with properly. This was followed by a rebuttal from the other accelerator companies, PowerLogix included. Newer takes a hardware approach to dealing with the speculative addressing issue, turning off speculation in input/output space but leaving it on in RAM/ROM space. The other manufacturers take a software/firmware approach. The issue with the software fix is that the patch can be erased in the unlikely event you "zap" your NVRAM. You should note that NVRAM and PRAM zaps are two different beasts and zapping your PRAM (a useful troubleshooting procedure) will not remove the SA patch. PowerLogix provides an emergency startup floppy which will boot your machine and restore the NVRAM patch if needed.

AltiVec Update!

When we originally reviewed the G4/350 and G4/400 we noted the lack of publicly available AltiVec plug-ins for Photoshop. As of December 10th, Adobe has made these plug-ins available on their web site. We noted this in a recent Product Watch Page. Before rushing off to Adobe's download page a couple of caveats are in order. The plug-ins will only work with Photoshop 5.5 so don't bother downloading unless you own this version or later. Adobe also makes no promises when it comes to using their plug-ins with G4 upgrade cards. Although we haven't had a chance to test for ourselves, I would assume that Adobe is just covering themselves legally rather than anticipating problems. If you own a G4 upgrade card and are using the plug-ins successfully or not so successfully, let us know! Post your experiences on our discussion board or send a note to Don.

Hardware Installation: Due to its compact design, handling and installing the card was a little unnerving. It was quite a challenge to avoid touching the card's circuitry as there is little unused space on the card. Other that this minor quibble the process was straightforward. The manual includes instructions for all of the supported machines. The fan's wiring harness includes a passthrough connector in case you have maxed out your power supply's feeds. One of my favorite design features is the strategically oriented 8 dip switches for adjusting the card's speed. Even once the card is installed, the switches are visible and easy to get to. I overclocked the 350 card to 400MHz without having to remove the card. Just make sure the power is off! In another nice touch, PowerLogix pastes a chart of possible dip switch settings on the back of the card for quick reference.

Performance/Stability: The cards operated very well at their rated speed. Both cards can be overclocked so, at the suggestion of PowerLogix, I set both cards to 50MHz over their "native" speed. The G4/350 jumped up to 400MHz (backside cache at 200MHz) without skipping a beat and closely matched the performance of the G4/400 across the board. Pushing the 400MHz card to 450MHz was more problematic. I experienced repeated crashes during the boot process and stalls when trying to load the finder. Booting with extensions disabled allowed a successful boot but on these occasions only one of the 9500's two hard drives would mount. Setting the backside cache to a 5:2 ratio (180MHz) fortunately eliminated all of these issues but also caused a performance hit over the more desirable 2:1 (225MHz) ratio. See scores below for a comparison of native vs overclocked speeds. Some cards may have more "headroom" than others so your mileage may vary.

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 G4/350/175/1MB PowerForce G4/400/200/1MB
Company: PowerLogix PowerLogix
Rating: (5 possible) (5 possible)
Hits: Excellent performance & stability even when overclocked to 400MHz, easy access to dip switches, 3 year warranty Excellent performance & stability at native speed, can be overclocked to 450MHz, easy access to dip switches, 3 year warranty.
Misses: Small size makes it awkward to install. Can't maintain 2:1 cache ratio at 450MHz without instability, small size 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. Remember, MacBench 5.0 came out well before the G4 processor and was consequently not written to take advantage of or test the AltiVec (AKA Velocity) instruction set.




"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 with the exception of the last test, we didn't use a "Velocity/AltiVec" plugin as neither PowerLogix nor Adobe provides one. You should also be aware that the plugin (including the one that ships with new G4 systems) doesn't provide a performance boost across the board, just on specific filters and operations.





Just to give you an idea of the AltiVec advantage, we ran a test using the Photoshop plugin that XLR8 provides with their cards. We ran the same filter operation twice for each card, once with the plugin and once without. The filter operation without the plugin was assigned a score of 100. As you can see, the plugin makes a bit of a difference!

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 for the 350MHz card overclocked to 400MHz were not included as they were virtually identical to the "native" 400MHz card.


Card Stats.
Manufacturer -Card


Cooling System

Variable/Fixed Clock Rate

Tech Support


PowerLogix PowerForce G4/350/175/1MB PCI Heat Sink/Fan combination Variable

Toll Free Phone

3 Years
PowerLogix PowerForce G4/400/200/1MB PCI Heat Sink/Fan combination Variable Toll Free Phone
3 Years