SCSI2SD performance issues.

[sailingdarter]

Greetings Classic Mac Hive Mind,

I recently purchased a SCSI2SD V6 board and I also got the following SD card for it


SanDisk 256GB Ultra SDXC UHS-I Memory Card - 100MB/s, C10, U1, Full HD, SD Card - SDSDUNR-256G-GN6IN

I was able to get the board updated to the lasted firmware and I got the card formatted with 2 HFS+ volumes (each 128GB). I am testing the card on a PowerMac 8600/350 (350 Mhz Mach V 604ev) on its SCSI 2 Bus. I cloned the main boot volume to one of the partitions and I was able to boot from it. But when I ran a disk benchmarking tool on it I was a little disappointed with the performance. I know not to expect SSD performance but I was expecting it to be faster than the mechanical hard drives from the late 1990s. At least that is what I was led to believe from this video The only tool that I had (on hand) to do a benchmark was Norton System Info. And it clocks the SD card at around the performance of a 68040 PowerBook HDD performance. Which is worse than the current SCSI HD that I am using with this machine.
Below are the benchmark results for Disk I/O

And here are the settings that I have configured for the board.

Any idea of what I may be doing wrong or mis-configuring? I have seem demonstrations of much better performance so I am sure it is something that I am doing.

Thanks in advance


P.S. Also I forgot to mention. The PowerMac 8600/350 is running Mac OS 9.1 and it has 320 MB of RAM

Cheers

 

[TzunamiOSX]

Read under Specs:

SCSI2SD V6 Rev. 2020d

store.inertialcomputing.com

Max. Performance is 10 MB/s under good conditions.

This adapter is more interesting for 68K or Nubus Macs. For a PCI Mac a PCI-IDE-Controller with SATA to ATA adapter is best option.

 

[TzunamiOSX]

Did you connect the SCSI2SD to right port? The Lower port is limited to 5 MB/s

This is a faster option, too

New CF AztecMonster

 

[sailingdarter]

Oh I have no doubt that I would get better performance from an IDE card. However, I would have expected the SCSI2SD to perform better than the real SCSI drive that it is replacing. Which is a 6GB Quantum SCSI drive. My hope was to simply to better the Quantum drives performance. Additionally I figured that an SD card would have no problem saturating a 10MB SCSI Bus.

As for checking which bus it is using. I have not verified that yet but I will check.

Right now though I am only getting slightly less than 1MB per second throughput. If this were a Quadra or a NuBus PPC Mac I would be okay with that but I would think that a late Gen 604ev could do better. Especially with SCSI-2

None the less I do appreciate your input. Thanks very much

 

[TzunamiOSX]

The upper port is a Fast-SCSI port who is limited to ~10 MB/s. You can get much faster SCSI but only with a PCI Cards like a Ultra (20 MB/s) or Ultra-WIDE-SCSI Card (40 MB/s) for example.

With an IDE drive you can get arround 25 MB/s limited to the architecture.

 

[sailingdarter]

Okay, for benchmarking sake I put back the original Quantum Fireball drive and ran the same benchmark and I got the following result.

So even if at the WORST case scenario the SCSI 2 SD were to match this result, I would be okay with that. But since it is benchmarking at 1/5th the speed, that is making me think that I am mis-configuring something. Although I have yet to open up the machine to physically check the busses, I did check in System Profiler and I noticed the following.

The drive is sharing the same bus as the Optical Drive and the internal Zip. So I am not sure if SCSI Bus 0 is the internal bus or external bus but it was physically on the same ribbon chain as the aforementioned devices.

I will open the machine tomorrow and check, but I am calling it a night for now.

Once again thanks

 

[TzunamiOSX]

Okay, for benchmarking sake I put back the original Quantum Fireball drive and ran the same benchmark and I got the following result.

View attachment 1732587

So even if at the WORST case scenario the SCSI 2 SD were to match this result, I would be okay with that. But since it is benchmarking at 1/5th the speed, that is making me think that I am mis-configuring something. Although I have yet to open up the machine to physically check the busses, I did check in System Profiler and I noticed the following.

View attachment 1732588

The drive is sharing the same bus as the Optical Drive and the internal Zip. So I am not sure if SCSI Bus 0 is the internal bus or external bus but it was physically on the same ribbon chain as the aforementioned devices.

I will open the machine tomorrow and check, but I am calling it a night for now.

Once again thanks

You can add up to 7 Drive to a FAST SCSI cable. All drives are workig with full speed. SCSI is a bit complicated to configure if you don't have the basics.

Every drive must have a unique ID and both sides of the cable must be terminated (nomally the controller is self terminating, so you need to terminate the last drive only)

SCSI Examples

 

[sailingdarter]

Well I opened up the case and found that it was on the "upper" Port.

 

[TzunamiOSX]

Can you tell me the row of the drives on the cable?