Legacy Macs on Steroids--Part 1

All Macs become legacy Macs of sorts in 6-12 months but we have two older legacy Macs, a PowerComputing PowerBase 180 and a Power Mac 7300. Neither came with a G3 or G4 CPU, USB or FireWire ports. They came with a minimal 16 MB of RAM and have small 1.2 GB and 2 GB hard drives and slow 8x and 12x CDROM drives respectively. They also have slow 40 MHz and 50 MHz system buses and slow onboard graphics. But they are easy to upgrade with CPUs on daughter cards, 2-8 RAM slots and 3 PCI slots. Neither legacy Mac in stock configuration is worth more than a couple of hundred dollars. With the price of G4 CPUs, RAM, hard drives and CD-RW drives at all time lows we decided to see how well these two legacy Macs would perform if we upgraded them to the "hilt" with just a few hundred dollars.

The New Parts

We obtained a PowerLogix PowerForce 450 MHz G4 CPU. They were selling for $279 at SmallDog.Com. The maximum RAM chip size that the PowerBase can take is 64 MB and there are only two slots besides the first which only takes a single-sided 8-32 MB chip for a maximum of 136-160 MB. OWC has the 64 MB RAM chips for $33 each. We already have a variety of 5v RAM chips of 8, 16 and 32 MB so we have 208 MB for the 7300. The PowerBase came with an IDE drive and the 7300 a SCSI. SCSI is still expensive so we looked for a cheap ATA drive and found a lonely 10 GB Maxtor ATA drive for $50 at our local Staples. A 20 GB would have been only $90 but 10 GB is enough. Finally, CompUSA had a Sony CRX160E 12x8x32x CD-RW ATA drive for $70 after a $30 rebate. The total cost was $466. We already had the requisite ATA controller card, a Sonnet Tempo ATA/66 which goes for $100 new at OWC. Finally, we installed Mac OS 9.1. In a subsequent part of this series we will attempt to install Mac OS X 10.0.4.

Installation

First we installed everything in the PowerBase, ran our tests and then moved everything to the 7300 and ran the same tests. We also ran the same tests on our 450 MHz Power Mac G4 Cube for comparison.

PowerBase. We pulled the stock 180 MHz PowerPC 603e CPU and 256 MB L2 cache and inserted the PowerLogix 450 MHz G4 card. The G4 has a small fan attached with a power cable that has to be connected with one of the drive power cables. The two 64 MB RAM chips snapped into the two available RAM slots on the motherboard. The PowerBase comes with and IDE hard drive and a SCSI CDROM drive. It has a built-in IDE controller on the motherboard but we could not get the Maxtor hard drive and Sony CD-RW drive to work on a single IDE cable so we had to use the Sonnet Tempo controller in a PCI slot. We ran a cable from each of the Tempo's two connectors separately to the Maxtor and Sony.

We fired up the PowerBase and installed and fully updated Mac OS 9.1 on the Maxtor along with the PowerLogix software for enabling the G4's L2 cache and Altivec engine. One of the best things about PowerLogix's CPU upgrades is that you can adjust the system bus speed and CPU ratio to get maximum performance. We adjusted the PowerLogix G4 for maximum performance starting with a system bus speed of 40 MHz, the PowerBase's stock speed and a CPU ratio of 9, the maximum. This yields a CPU speed of only 360 MHz (9x40) for the 450 MHz G4. Step by step we raised the bus speed to 46.5 MHz giving a CPU speed of 420 MHz (9x46.5). Unfortunately, 50 MHz was unstable so we couldn't get to the full 450 MHz rating of the CPU. We set the backside cache at 210 MHz because it would not run at the next highest setting of 280 MHz. Still, t420/210 is much faster than the stock CPU and nearly as fast as our G4 Cube at 450/225.

We also installed iTunes 1.1 and fully updated Authoring Support to 1.1.2 using TomeViewer since the installers wouldn't run. We used TomeViewer to install Disc Burner 1.0.1 as well. The Maxtor ran fine, booting the PowerBase but the Sony CD-RW would only work as a CDROM drive--more on this in Part 2.

7300. The PowerLogix 450 MHz G4 replaced the stock 180 MHz PowerPC 604e CPU. We connected the G4's fan to the hard drive power cable and added the additional RAM. The 7300 comes with a SCSI hard drive and a SCSI CDROM drive and no IDE (ATA) controller. We inserted the Tempo ATA controller in a PCI slot and connected the Maxtor and Sony drives with separate cables from the Tempo controller. The 7300 has two hard drive bays so we kept the original SCSI drive connected in the second bay. We installed the same software as in the PowerBase. The Maxtor hard drive ran fine as the startup drive and iTunes recognized the Sony CD-RW drive and burned CDs. Toast also burned data CDs.

The 7300 has a stock system bus speed of 50 MHz so with a CPU ratio of 9, it runs at 450 MHz out of the box. Our 7300's system bus would not run reliably at 52.5 MHz so we kept the PowerLogix G4 at 450 MHz and the backside cache at 225 MHz, the same as our G4 Cube.

Performance

Here are the results of several initial benchmarks for our G4 PowerBase, G4 7300 and G4 Cube:

Test	G4 PowerBase	G4 7300	G4 Cube
Altivec Fractal Carbon (megaflops)	1.2	1.5	1.4
MacBench 5 CPU	1138	1218	1141
MacBench 5 FPU	1405	1527	1512
Gauge Pro 1.1 (MB/s)	44	51	208
Virtual PC 4 Manual Scroll (sec)	58	64/47	36

All three computers appear to be fairly comparable in the MacBench and Altivec Fractal Carbon benchmarks. The Gauge Pro test shows that the faster system bus of the G4 Cube (100 MHz) can push data a lot faster that the 40 MHz bus of the PowerBase and the 50 MHz system bus of the 7300. And when it comes to doing work, the speed of the graphics subsystem also comes into play as scrolling the 144 page Virtual PC 4 manual in Adobe Acrobat 5 shows. The G4 Cube completes the scroll in 36 seconds, almost twice as fast as the 7300 or PowerBase. We reran the scroll test after installing a 3dfx Voodoo5 card in our 7300 and the gap closed significantly. However, in real world use no one really scrolls a whole manual since it is indexed and Acrobat allows one to skip directly to the page one wants.

What about real world use? And what about Mac OS X? Stay tuned for the next installment.

-- Weekend, September 8-9 --