PROS: Fastest and most feature laden PPC750 card to date.
  Ran 1:1 cache speeds at 292mhz reliably. Excellent control software.
  Outperforms the more expensive Newer Tech Pro+ 266mhz card.
  Test card runs reliably and cool at 292mhz, with cache at 1:1 ratio.
  Ran 65mhz bus/292.2mhz cpu in PowerCenter 132 (MacBench CPU score= 1147).
  Longest warranty of any PPC750 card.

  CONS: Pricey compared to 604E cards.
         Does not work with Adaptec SCSI cards

Updates:

• 12/6/97 - Verified that this card does not work with wide scsi drives and the Adaptec 2940UW card. The Cheetah Review was done with this card and the ATTO scsi card w/wide scsi Cheetah drive. So that card seems to be ok.
• 12/4/97 - Due to the size of this page (a lot of content!) I've separated the Applications test results to a separate page.
• 11/19/97 - Initial production of the Powerforce cards are not compatible with the Mach5 based 8600 lines (>250mhz). Later production versions will be per Powerlogix.

• 11/17/97 - Just wanted to note that backing off the bus speed to 45mhz eliminated the video artifacts I'd seen at thousands colors, on the builtin video. The card is still running rock solid reliable at 292mhz, and the 8500 built-in video is perfect. Card settings are A=7 (6.5x ratio) and B= 1(45mhz bus). I amazed the card has been perfectly reliable at this speed. Note that the X-Force 250 also uses this card, and my review system's card is running at 285mhz.

• 11/4/97 - Attention PowerBase Owners! - The PowerForce G3 works in your system! Read the PowerLogix Press Release.
• 11/3/97 - Register to WIN a PowerForce 250! I did!
• 11/2/97 - added results of MaxPowr Pro+ running 45/266/266 (1:1 cache) w/60ns memory timing.
• 11/1/97 - retested and updated times for PS4 G.Blur tests and 80meg PS allocation rotate test.
• 11/1/97 - added results of MaxPowr Pro card with new control panel, running 45mhz bus/166mhz cache/250mhz cpu and 60ns memory setting. The new control panel allows a faster 1.5x cache bus ratio, vs. the previous 2x setting. For more details on the MaxPowr Pro - see my separate review.
  ** MaxPowr Pro tests were run after desktops were rebuilt on all disks, and the Photoshop Swap File disk was optimized (long story). Therefore the Photoshop tests with the Powerforce will be redone to verify that the listed times are still correct with the optimized disk, and that the Macbench disk score is still representative of the PowerForce performance on the optimized disk. **

Introduction:

Lightning strikes twice. Powerlogix has one-upped the competition again - this time in the PPC750 card arena. Just as they did with their PowerBoost Pro line, Powerlogix again provides the power-hungry Mac owner with the best in CPU Upgrades. The new PowerForce G3 cards are the only current upgrade (or system for that matter) that has a backside cache running at the full speed of the processor. (Update: Newer Technologies new Control Panel allows a 1:1 cache on the Pro+ card, but the card is limited to 266mhz speeds, whereas the PowerForce 250 has run a 292mhz 1:1 cache - I've also recently done a review of the Newer 275/275 card as well.) This technology doesn't come cheap however, and the price reflects this exclusive status. But if you desire to have the absolute fastest Mac possible, or if you use your Mac to earn a living - this card is your dream come true. For owners upgrading 120mhz or slower machines, I'd suggest you fasten your seat belts before takeoff. The change in speeds from my stock 8500/120 was dramatic to say the least. The PowerForce card's MacBench CPU scores were almost twice that of the best 604E card I've seen, the PowerBoost Pro 233 running at 263mhz.

Comparison with the NewerTech MaxPowr Pro+:
Thanks to Mac CPU, I've had the opportunity to test the MaxPowr Pro+ as well. As luck would have it - Newer Tech. had just released a revised control panel that allowed the Pro+ to run at 1:1 backside cache speeds (prev. max was 1.5:1) and a more agressive 60ns memory timing setting.

As shown in the application tests and MacBench scores, the Pro+ did not match the PowerForce performance, primarily due to the fixed processor speeds I believe. The 250mhz PowerForce card was able to run at 292mhz reliably, even at the 1:1 cache ratio setting, whereas the Newer 266mhz card does not allow the CPU to be accelerated beyond its rated speed. For this reason, and the fact the PowerForce 250 actually costs less, performs better and has a longer warranty I consider it the "best buy" among the high-end PPC750 cards.

My current MacBench CPU scores for the PowerForce G3 250 are higher than those shown at Newer's MaxPowr Pro+ Macbench page - where they show a score of 1078 for a 275/275/45 (275mhz cpu/275mhz cache/45mhz bus), vs. my 1130 at the current 292/292/48 (w/o motherboard cache) - and this is only Powerlogix's 250 card. I personally find the Newer chart somewhat deceptive, as their fastest Pro+ card does not offer a 275mhz cache or CPU, only a 266mhz cpu/266mhz cache (and until the last few days when their new control panel was released, their max cache speed was 177mhz).

Even at 266/266/45 with the 60ns memory timing settings, the Pro+'s CPU score of 1048 trailed the PowerForce 250's score of 1130 in the same system. Newer shows the Pro+ at the former cache speed (266/177/48) scoring 972, indicating that the new faster cache & memory settings are worth 76 CPU points.

The PowerForce Difference:
In addition to the full CPU speed backside cache (at speeds up to 300mhz), PowerLogix again distinguishes itself from the competition by providing a wide range of bus and processor speeds on the PowerForce card. In addition, the backside cache speed is adjustable via the PowerForce control panel. Although the remote control found on their PowerBoost Pro is not used, bus speed and ratio settings are easily made via two rotary switches on the back of the card. Unlike my pre-production card, all production PowerForce cards will have right-angle rotary switches to allow easier adjustment while the card is installed.

Another reason for the price and performance differences is the speed of the cache static rams used. The PowerLogix PowerForce 250's use IBM 4ns (nanoseconds) chips, the PowerForce 275's use 3ns (!) versions. The Newer Tech MaxPowr Pro uses much less expensive 7.5 Micron cache, and the Pro+ version uses the IBM 5ns static ram. This helps explain both the cost and performance differences of the various 750 cpu cards, as the cache is both a major cost and performance contributor.

1. Indicates backside cache size
2. Allows enabling/disabling cache
3. Allows changing Cache Speed (ratio)
4. Option for 603E compatibility mode

I've run all tests with the cache ratio at 1.0 (full cpu speed), and without 603E compat. mode enabled and have not had any problems. Some software that expects to ID the cpu or Gestalt of the machine may need the 603E Compatibility mode enabled. PowerLogix says the game "Mechwarrior" is one example.

Some readers have asked why there is an option to increase the ratio of the backside cache (which runs the cache slower than the CPU). PowerLogix provided that option for those that run the CPU beyond 300mhz. At speeds above 300mhz the backside cache may not be able to run at the 1.0 ratio reliably. For owners of the 275mhz card, who may be able to run the CPU at 330mhz or more, this option may provide the most overall performance. With the 250mhz card, I doubt that I can run the CPU at 300mhz, so my best performance will be using the 1.0 ratio (full cpu speed).

Why does PowerLogix provide all these options?
For Maximum Performance. It's that simple. The more choices you have for tuning the card the better performance you can obtain from your Mac. Maybe you don't feel comfortable with adjusting or experimenting with the different settings right now, fine - just use the default (stock) settings. But later on you'll be glad they are there, when you become more comfortable with the technology and desire to squeeze more performance out of your original investment (as much as 30% in some cases).

Once you've determined your needs and price range, always buy the product with the most speed settings, features, and performance. In the past (before the PowerLogix Pro), there was usually a need to compromise. Not so any more, you can have it all. For the same price and quality, why would you choose less options and performance? Personally, I'm a little disappointed that other vendors have not seen fit to follow suit.

What about motherboard cache?:
With the PowerForce 1 meg backside cache, many readers have asked whether they have to remove their existing L2 cache (in Mac models that have socketed L2 cache modules) and if the card is compatible with the fixed 512k cache models like the PowerMac 95/9600, and some Umax models based on the same motherboard design. According to Powerlogix the answer is no, you don't need to remove any cache, and yes (compat. with 9500 and similar models with nonremovable cache). I have run the PowerForce both with and without the PowerLogix 1meg Rapidcache installed on the 8500 motherboard - and have had no problems in either configuration.

Without the motherboard cache installed in the 8500, I achieved a slightly faster bus speed, and therefore higher processor speed (same 6X bus to cpu ratio was used). The Macbench chart below shows the results of both configurations, as does the application scores listing. Note that some Newer Tech Pro owners have reported that removing their motherboard cache increased performance, although others claim the opposite.

As far as reliability goes, this card has been flawless in operation, with not one problem seen during hours of application use - all while running the card at 285mhz. (**Update: With the motherboard cache removed, I'm now running 48mhz bus/292mhz cpu speeds with a 1:1 cache ratio reliably.) Call it design headroom, or performance margins, or whatever you like, I consider this a testimony to the quality of the design and components of the PowerForce card. The card also ran stone cold as well, generating absolutely no detectable hot spots on any portion of the card after several hours of use.

Ongoing tests:
In order to make performance results available to readers promptly, I'll be updating this page almost daily, as I perform tests at various combinations of bus, cpu speeds and cache speeds. This will allow you to have a good picture of overall performance at the stock settings, and for the more advanced user, at the maximum reliable speed settings. Choice of speed ranges is a welcome hallmark of the PowerLogix cpu card line, and I applaud them for continuing to incorporate this into their card designs.

Installation:
Installation is a breeze. First, install the control panel software, then shut down your Mac. Set the PowerForce speed switches to the desired settings as shown in the manual. Remove your existing CPU card, and while it's out press the motherboard reset switch (hold for 20 seconds) to ensure that the new CPU card will be recognized at startup (btw - you'll have to reset your date and time). Insert the PowerForce card - ensuring that it is fully seated and power up the Mac. Note that the PowerForce card is a low profile one, which means it will not be supported by the 8500 style latches. (I was apprehensive about this lack of vertical support in the 8500, but PowerLogix assured me it is not a problem.) Open the control panel and set the PowerForce operating modes desired. Restart the Mac to ensure these settings are working. Congratulations - you're now running the fastest Mac on the Planet!

PowerForce Compatibility:
PowerLogix lists the following Mac's and clones as "100% compatible" with the PowerForce:

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

Backside Cache - large and fast:
The current Macintosh designs bus speed bottleneck is why cache is so important, as cache buffers the CPU from this slower "pipe". Cache contains very fast specialized ram that allows the CPU to run at its full speed without waiting on slower devices like Ram and disks. The larger the cache the better able it is to keep a fast CPU "fed" so to speak. When data is not in the cache, the CPU must wait on slower ram or disk access to process data.

The PowerForce card combines both a 1 meg backside cache, and the fastest possible access to it (the cache runs at the full CPU speed). No other CPU card currently on the market runs a cache this fast. In addition, the PowerForce control panel allows you to change the cache speed to ratios other than 1:1. Why would you run it at less than the full CPU speed? The only reason would be if you're running the CPU at speeds of 300mhz or higher, where the cache could not reliably run at this speed. Increasing the ratio would allow you to run cache access slower, increasing reliability at these elevated CPU speeds. The overall performance of the higher CPU speeds may be worth the tradeoff of slightly slower cache access in some cases. I'll expand on this topic further in the future, as I explore what the limits of this particular card is in future updates.

I must say I've been impressed, as I'm running this card at 292mhz, with the cache still at 1:1 (292mhz) and it's been rock solid. Not one error of any kind in repeated heavy application use. I find this comforting after seeing the trials of many aftermarket L2 caches which have problems running at 50mhz speeds. If there is still any doubt in anyone's minds about the quality of this card or its exclusive 1:1 cache static ram's - I think you can put that one to rest. The proof is in the pudding as they say. B>Remember: Speed without Reliability is Useless.

Operation at 292mhz CPU/Cache speed was rock solid reliable through Photoshop, After Effects, Infini-D 4.0, MacBench 4.0, and even Quake (both RAVE and 3Dfx versions). That could mean that this 250mhz card has even more performance headroom. I did note an odd video artifact in the file selection areas of the file open dialog boxes (the black highlighting had some extra lines through it) on the builtin 8500 video (not the ATI RagePro card though), but otherwise video was flawless. This may be due to the fact I have mixed Vram in my 8500 (a pair of 60ns & 70ns vrams). **Update: Changing color depths to 256 or millions colors solves this problem, as reported at Brett Harris's MaxPowr Pro Issues page. I'll admit that his page examples looks worse than what I've seen with the PowerForce card with my 8500 video. (***Update: Reducing the bus speed to 45mhz eliminated the video artifacts completely with my card, still running at the 292mhz speed.) Otherwise video performance was flawless - and not a single error during hours of heavy application use. This thing really grows on you, as it is very, very responsive.

As a side note - I removed the PowerForce card after several hours of use to test for any heat problems. No area of the card or heatsink was even warm to the touch. That surprised me, even though the 750 cards run much cooler than the 604E cards due to lower voltage and die size, I expect to feel some warmth on the heatsink. Not a bit. This bodes well for long term reliability in my experience.

As with all PowerLogix CPU upgrades, this product carries a 30 day money back guarantee and a 3 year limited warranty. Over-clocking the card (running the cpu at higher than rated speeds) does not void the warranty.

Base System Notes:

The base system used to test the PowerForce^TM was our standard PowerMac 8500, with 128megs of matched memory (60ns), standard built-in video with 4 megs Vram, running OS 7.6.1. A Power3D card and ATI Rage Pro were also installed, but all tests were run from the 8500 video monitor. Disk cache was 512k, Speed doubler 2 and LibMoto were active (Speed Doublers faster disk access was disabled). Quicktime 2.5 and Quickdraw 3d extensions were also enabled (as done in prev. testing).

All tests were run using MacBench 4.0 . All graphics tests were run at 1024x768, thousands of colors , not the lower resolutions and color settings used by most of the magazine reviews. We feel our settings are more in tune with actual users. Consider this when evaluating the video scores.

• PowerPC 750 processor rated at 250mhz
  (Powerlogix stated this card had run 290mhz reliably)
• Backside cache size: 1 MB
• Maximum Cache Speed: 250mhz (stock) to 292mhz (tested)
• Selectable Bus speeds from 40mhz to 75mhz in 16 increments.
• Selectable Cache speeds from 1:1 to 3:1
• CPU/Bus ratios of 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1
  

The additional speed settings that can be used show that the design has substantial performance "headroom" beyond the rated CPU speed - a welcome bonus.

PowerLogix deserves an award for technical excellence for such an outstanding design in their first 750 card. It seems they've won the triple crown this year - best cache, best 604E card and now best 750 card. No small feat from one company in less than six months. Update: The PowerForce cards seem to have a problem with the Adaptec SCSI cards (just as Newer s first G3 cards did), although the Atto, Initio and JackHammer cards seem to run fine based on my SCSI tests.

2/28/98 Availability Update: - It appears the PowerForce 250 cards are sold out, and no more will be made. I'm glad I have one, as it is the finest CPU card I've ever owned. PowerLogix is now in the process of making 275mhz and faster cards (they say the 275/275 is tested at 300/300 before it leaves the factory). Watch the main site for a review of this card soon!