"BARE facts on Macintosh speed FEATS"
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Originally posted 07/18/03 by rob-ART morgan, mad scientist This the continuation of the article is comparing the new AEC-6885MS 4-CH High Scalability ATA133 RAID PCI Host Adapter from Acard. We're comparing it running 4 drives in RAID 0 configuration to FireWire 800 four drive RAID 0 (both 2 and 4 channels) and Ultra320 SCSI four drive RAID 0 (both 2 and 4 channels). REAL WORLD TESTS 
ANALYSIS 1. Is the AEC-6885MS 4-CH High Scalability ATA133 RAID PCI Host Adapter card faster than two 2 channel AEC-6880M HW RAID cards? In 4 out of 7 tests, the 6885MS was significantly faster. In the remaining tests, it was slightly slower. Add to that the fact that it uses only one slot and supports three modes of HW RAID and the 6885MS becomes a clear winner over its "brother." 2. Which produces a faster 4 drive striped array (RAID 0), ATA-133? FireWire 800? or Ultra320 SCSI? Surprise. The FireWire 800 four drive, four channel setup was the clear winner in 4 out of 7 tests. And it was a close second or third in the other three. 3. If cost is the factor, setup is the best buy? If you have room inside your tower for four drives in addition to the boot drive, the Acard 6885MS scenario is the least expensive. The FireWire 800 scenario costs more because of the required enclosures, but is cheaper than Ultra320 SCSI. Plus it has the advantage of "living" outside the box. Therefore, I rate FireWire 800 RAID the best buy. 4. So why didn't the 320MB/s Ultra SCSI setup blow the others away? It's partly the fault of drive technology. Though the SCSI drives ran at twice the rotation speed of the ATA drives (15,000rpm vs 7200rpm) and require half the average access time (3.6ms vs 8.5ms), that just wasn't enough. They are not twice as fast. More like 38% faster. (75MB/s vs 54MB/s sustained READ). And though each channel can handle three times the throughput (320MB/s vs 100MB/s or 133MB/s), apparently that's not enough either. I think the main bottleneck is the Power Mac G4's PCI bus controller. That's makes sense when you consider I used the same UL4D controller on a Dual Xeon with 100Mhz PCI-X slot and got TWICE the speed.  5. Take another long look at the graph above to see what the G5 Power Mac potentially offers us, thanks to the new 100MHz and 133Mhz PCI-X slots. It will be interesting to see how well the parallel and serial ATA host adapters do on the PCI-X bus. We've already tested a multi-channel FireWire 800 PCI-X card in the 100Mhz PCI-X slot of the Dual Xeon. But it was no faster than using multiple single channel cards on the G4 Power Mac.
TEST NOTES The Power Mac G4/1.42MP with 2GB of DDR memory and OS X (10.2.6) was the test mule. CONTROLLERS AND DRIVES TESTED The AEC-6885MS 4-CH High Scalability ATA133 RAID Adapter connected to four drives (two Hitachi 180GXPs and two Maxtor DiamondMax Plus 9s). AEC-6885MS can be ordered direct from Acard or dealers listed on their site. Your favorite Ultra ATA drives can be ordered from OWC, TransIntl, and GoogleGear. Two AEC-6880M dual channel ATA HW RAID Adapters connected to four drives (two Hitachi 180GXPs and two Maxtor DiamondMax Plus 9s). The four drive, four channel stripe was created by taking two HW striped pairs and making them a SW striped pair using Apple's Drive Utility. AEC-6885MS can be ordered direct from Acard or their dealers. The four channel, four drive FireWire 800 RAID was created using three FW800 PCI cards in conjunction with built-in FW800. (Using four PCI cards was much slower than three with the internal FW800 port.) The four enclosures included two Mercury Elite Pro FW800 enclosures from Other World Computing and two IceCube800 enclosures from FWDepot. The four drives were Hitachi 180GXPs. The two channel FireWire 800 RAID is similar to above except only two PCI cards were used. The four channel, four drive Ultra320 SCSI array was created using both the ATTO UL3D and UL4D dual channel Ultra320 controllers with one drive on each channel. Two drives were Seagate Cheetah 15K.3 and two were Maxtor Atlas 15K. The two channel Ultra320 SCSI array was done by putting two drives on each channel. Results for both the UL4D and UL3D are posted to show that the UL4D is overkill on the G4 Power Mac. But on the G5 Power Mac, you should see it pull away.
SEE "HOW WE TEST" for details on the tests reflected in the graphs.
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