My base system: PowerMac 7500/200mHz 604eMaxPowr/50mHz bus/208mb RAM/6656 Diskcache/4.5gig Cheetah Narrow/1mb RapidCache/Mac OS 8.1 plus latest updates/ HFS+(CharisMac Anubis 3.01 driver)

INSTALLATION:
The floppy disk came with the latest three extension for 1:1, 1.5:1 and 2:1 backside cache ratio’s. You are instructed to use only one of these at a time.

The RailGun came with a fan which is mounted on the heat sink. It has a connector which I plugged in between the power supply to my hard disk and the internal 1mb Jaz drive, after calling BottomLine’s tech support to confirm this. (Note: The fan and cable are NOT described in the documentation and the wire connecting the fan to the power cable adapters is 2-3 inches too short to allow the 7500 bay to fold out fully. So one has to either unplug the fan from the 7500 power supply cable or carefully allow the full weight of the drive bay to tug on the fan’s wires.) Otherwise the card just plugged in.

I initially removed the 1 mb RapidCache level 2 cache. But, as others have described, the 7500 would not boot at all with the RailGun card. I took the advice of others and put the 1 mb RapidCache back in and the computer booted up! I have one of the early generation of PM 7500’s. So all subsequent evaluation was done with the now Level 3 RapidCache 1 mb in place.

The card came with the preset speed of 299/299 when using the 1:1 backside cache ratio. Switch A-(bus ratio) set at 8 = 7:1. Switch B-(bus speed) set at 8 = 42.67. The maximum possible settings would be 360/360 (Switch A = A = 8:1, Switch B = F = 45.0)

The highest speed I was able to attain at a 1:1 backside cache ratio was 310/310 (Switch A = 8 = 7:1, Switch B = D = 44.33). I have not tested this speed extensively with RAMometer 1.3 yet.

The highest speed I was able to boot at with the 1.5:1 extension was 341/227 (Switch A = A = 8:1, Switch B = 8 = 42.67). However this was somewhat unstable and MacBench 4.0 crashed during the graphics test at this speed.

So I dropped the speed down 2 notches to 336/224 (Switch A = A = 8:1, Switch B = 6 = 42.0) which has been solid for the last 24 hours. I ran RAMometer 1.3 overnight and had no reported errors. (Note: With the multiple crashes during tuning, I did have some minor file corruption, which I successfully repaired with Disk FirstAid 8.1 and TechTool Pro 2.0.2.)

The highest speed I was able to attain with the 2:1 extension was 341/170 (Switch A = A = 8:1, Switch B = 8 = 42.67). This slightly higher CPU speed didn’t seem worth the cost in backside cache speed.

PERFORMANCE
200mHz 604eMaxPowr/50mHz bus/208mb RAM/6656 Disk Cache

Start up-Only OS 8.1 All: 1:17 (min:sec)
Start up-OS 8.1 plus all 3rd party extensions: 1:56
Open Netscape 4.0.5: 0:08
Open Photoshop 4.0.1: 0:10
Open Illustrator 7.01: 0:15
Open Word 98: 0:09
Open VirtualPC 2.0/Win95: 0:52

RailGun G3 300 at 336/224/42.0/208mb RAM/6656 Disk Cache

Start up-Only OS 8.1 All: 1:09 (min:sec)
Start up-OS 8.1 plus all 3rd party extensions: 1:39
Open Netscape 4.0.5: 0:05
Open Photoshop 4.0.1: 0:08
Open Illustrator 7.01: 0:11
Open Word 98: 0:06
Open VirtualPC 2.0/Win95: 0:28

MacBench results
The tests with the 200mHz 604e and initial test with the RailGun G3 300 were done with Conflict Catcher 4.1.1 set for Mac OS 8.1 All. Thus, LibMotoSh was not running on these two tests. Subsequent tests were done with LibMotoSh enabled in addition to only Mac OS 8.1 extensions running.

The RailGun G3 300/300/1mb gives me twice the CPU performance compared with the 200 mHz 604e with 1 mb RapidCache. Interestingly, the RailGun G3 300 CPU scores all max’ed out around a MacBench score of 1200, whether the ratio was 1:1, 1.5:1 or 2:1.

Subjectively, the RailGun gives snappier finder performance which is nice, but not as much as I had hoped for. The largest improvement seemed to be with VirtualPC 2.0, cutting the launching almost in half and giving quick responsiveness on the Windows 95 desktop. I haven’t done much real image editing work with Photoshop or Illustrator yet, so there may be some significant time savings there.