The XLR8 400/200/1MB CPU card contains a IBM 400MHz PowerPC 750 CPU (aka G3) and 1 MB of backside cache. The card was obviously a production version with no sign of any circuit mods or post-build reworks that would indicate a pre-production or design change modification. The G3/400 is an new improved design from XLR8 and based on results I've seen the reports of cleaner signals than many past G3 CPU cards appears to be true. The card plugged and played in both the 9600/350 and Genesis systems despite the fact it was set for a 50MHz bus speed. No other G3 card I've tried to date would run those speeds in the Genesis or 9600 (I have two adjustable speed G3 cards that can be set to 50MHz bus speeds and higher).

You couldn't ask for better reliability than I saw during extensive testing over 3 days - zero errors. I fully exercised the card in applications tests, large program CDrom installs, copies to/from the ZIP drive and copying the entire contents of the boot disk (2.8GB/tens of thousands of files) to the striped RAID array without a single error. If this card in typical (and GDTS says they have had nothing but great results) then I suspect the worries over G3 50MHz bus speeds being reliable in most Macs (some people projected a 60% failure rate) is unfounded.

Quality of workmanship was very good, with no cold solder joints, etc. seen. The heat sink made good contact with the CPU, and there was thermal compound between it and the processor. As mentioned previously, the card ran remarkably cool during the tests - never exceeding 24 degrees C in the 9600 or the Genesis. This is 30 degrees C cooler than my Apple G3/300 runs.

Based on my experience running this particular card in two different Macs (one with a history of being problematic with G3 CPU cards) I have to say I am impressed. I expected problems running 50MHz bus speeds in the Genesis at least.

Speed Settings:

Bus speeds of 40 to 60MHz are supported via XLR8's MVP (Multiple Variable Processing) switch. The stock bus speed setting is 50MHz with a CPU/Bus ratio of 8X (50MHz bus x8 ratio = 400MHz CPU). Faster speeds may or may not run reliably, as 50MHz bus speed for a G3 CPU card in most Macs is fairly unusual. Most current designs limit bus speeds to 45MHz. Any 400MHz G3 card must run at 50MHz bus speed however since the maximum CPU/Bus ratio is 8X.

The photo below shows the red MVP switch on the rear of the card that is used to adjust Bus speed and ratios.

For most owners I don't recommend changing the default settings. Systems like the PowerCenter Pro might possibly run at faster than 50MHz bus speeds. The only reason to do this would be to explore faster than 400MHz CPU speeds, which may void the warranty and may not be reliable. [Check with XLR8 on their current warranty policy, but the latest info I have is that they do honor the warranty regardless of speed settings,]

Although I did not (yet) explore faster speeds than the stock 400/200/50 setting of the card as shipped, bus speeds of 40 to 60MHz are selectable via the red switch on the back side of the card. Bus to CPU ratios of up to 8X can be selected so the theoretical maximum CPU speed setting possible is 480MHz.

I was surprised to see that the Radius Thunder 3D PCI graphics card worked without problems with the XLR8 400MHz card. My past tests with three other brands (Powerforce designs) would lock the system when loading the Radius extensions. Since OS 8.5 and this card are compatible that's a double bonus for this card that's was selling recently at NECX for $300 (it was $1699 list).

With the original shipping version (Oct 98) of the cache control, the common problem with Adaptec SCSI cards mounting wide drives (shared with all G3 CPU cards except the Newer Tech and Vimage models) was still evident (see below for an update on a new control panel that is said to solve this - released after the review in Jan 99). I had no problems running the card with dual ATTO PCI SCSI cards, and based on my SCSI tests in the past, I suspect the Jackhammer and Initio Miles cards are also compatible.

A backup with Retrospect failed just as it had with the PowerForce design cards. There is a workaround however; under the Special tab, hold down the option key and select Preferences. Select SCSI from the left column of choices, then disable (uncheck) "SCSI Manager 4.3". This reverts to synchronous mode and resulted in a 1.6GB back and verify completing successfully. Update: - New v1.2 Cache Control Panel addresses Retrospect/Adaptec SCSI compatibility according to reader reports and Macgurus.

XLR8 lists this card as compatible with the following Mac models:

• Apple PowerMac 7300, 7500, 7600, 8500, 8600, 9500, 9600
• Power Computing-PowerWave, PowerCurve, PowerCenter, PowerCenter Pro, PowerTower, and PowerTower Pro.
• UMAX Supermac S900, J700

The CPU Card has a removable metal bracket to allow use in low profile cases and Power Computing models.

Update: As of 1/1/99, only XLR8 seems to have a 400MHz G3 card that works in Mach 5 systems. As noted in the main site news in late December 98, there have been stability problems/compatibility issues with both the PowerLogix G3/400 and Newer Tech G3/400 cards in Mach 5 systems. Both companies are working on a fix readers tell me. The Mach 5 systems are 8600/250 and 300Mhz, and 9600/300 and 350MHz systems. The Newer Tech 400Mhz card owner said there were switch settings to allow it to work in his 9600/350 but he had to set the card speed to under 400MHz. He said Newer Tech was to resolve this issue very soon. MacGurus has a series of notes on this below the Newer 400Mhz card listing that has more details. These issues may be resolved by the time you read this, but as of 1/1/99 there were no confirmed reports of this.

The hardware design proved reliable in use and very fast. Until the Adaptec compatibility issue is solved I deducted one point for that, although it did not affect my hardware configurations. The stable operation at 50MHz bus speeds in both test machines (the best results so far in them) are reasons why I rated the hardware features/design a 9.

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