Here at Intech we are so often confronted with trying to solve hardware and firmware
problems, that we sometimes forget to emphasize that our drivers can in many cases be tuned up
(instead of down) to achieve some of the best performances possible across the various
interfaces capable of supporting mass storage devices on the Macintosh.
In many cases, users may not be getting the peak performance that their configuraion is
PERFECTLY capable of. This page, therefore, is dedicated to specifically showing
you how to get the MAXIMUM possible speed from your HDST controlled storage device.
Caution: This page will tell you how to get the greatest possible speed from your storage
device. Please note: NOT ALL CONFIGURATIONS WILL BE CAPABLE OF REACHING MAXIMUM POSSIBLE SPEED!
Always make a backup of your data BEFORE changing any settings, and test your drive thoroughly
BEFORE trusting it with critical information.
Intech's philosophy has always been to put the hightest possible priority on getting a particular drive
to function reliably. As such, many of the transfer related settings HDST chooses by default
upon setting up a drive favor compatibility over maximum speed. This page will take you through
the various supported interfaces and discuss the relevant issues and settings related to
performance for each interface.
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Systems most likely to benefit:
All Macintosh models with built-in Ultra DMA ATA busses
(Blue and White G3 and later models) with ATA drives THAT ARE
CONNECTED TO THESE BUSSES. Drives which are connected to the
non-Ultra DMA bus (the bus which had your original CD or DVD
drive connected) is already operating at maximum speed: multiword
DMA transfers at about 16 MB/sec max.
Systems who should be VERY careful: owners of the first revision of the Blue and White G3'machines. So how can you tell if you own one? It is not difficult, but you'll need to open up your machine and identify the IDE controller chip. It is located about an inch behind the Ultra DMA connector on your mother board. The chip has a big "CMD" label on it and starts with the numbers "646." If the number ends with a "-402" then you have a rev 2 machine and should not experience any data corruption problems.
If you have a rev 1 Blue and White G3 machine, we simply cannot recommend increasing the transfer rate unless you have only one drive connected AND it is the original Apple drive. If you have two drives on this bus, do not even think about running full speed! If you are replacing the original Apple drive with a bigger drive ONLY, you have about a 50/50 chance of being able to run the replacement drive at full speed. The only way to know is try it and then test it.
Systems who should not need to change: All Macintosh models made prior to the Blue and White G3 are already running at the maximum possible speed.
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The setting change:
If you are sure your drive is connected to an Ultra DMA ATA bus, then continue reading.
If you are not sure which bus a given drive is connected to, see the topic immediately
following this one before you proceed.
The top group of settings is called "ATA Timing Parameters". The first check box is labeled "Enable Ultra DMA." This will be checked by default. The popup menu to the right of the check box controls the DMA mode for Ultra DMA systems.
If you are on an Ultra 33 ATA bus, this menu will be set to "Mode 1" by default. To raise your speed to the max possible select the "Mode 2 (Ultra 33)" item from the popup menu. If you select a greater setting, the driver will reduce the drive to Mode 2 automatically.
If you are on an Ultra 66 ATA bus, this menu will be set to "Mode 3" by default. To raise your speed to the max possible select the "Mode 4 (Ultra 66)" item from the popup menu.
Click the "Done" button, quit HDST, and restart your computer. You should immediately test the drive's new setting BEFORE you trust it with your important data. Please see Chapter 7 of the "HDST User's Guide" for instructions on using Intech's Integrity application to test your new settings.
- How to know if your drive is connected to an Ultra DMA ATA bus: Run the HDST application program. Select the ATA drive you want to know about. Click the "Info" button (second from the left). In the information dialog which comes up, locate the "bus info" tab (it is the middle tab). Locate the last entry in the "bus info" tab which says "Available DMA Modes." If this drive is connected to an Ultra DMA bus it will say the word "Ultra" followed by the number of Ultra DMA modes supported by this bus. Three modes means an Ultra DMA/33 bus and five modes means it is an Ultra DMA 66 bus. If the ATA bus cannot do Ultra DMA, the world "Ultra" will be missing from this field.
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Systems most likely to benefit:
Macintosh QuickSilver models (733, dual 800, and 867 Mhz) and later. These
computers do not always negotiate the fastest payload size (2048 bytes)
automatically. To guarantee maximum speed, see instructions below.
Systems who should not need to change: All Macintosh models made prior to the Macintosh QuickSilver. Prior to the Macintosh QuickSilver, the default speeds tended to be the fastest.
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The setting change:
On the right side of the above dialog is the "Max Data Transfer Size" popup menu. The
HDST driver, by default, will use the fastest possible setting when left at auto, so
only adjust this parameter if you are having problems, not trying to get more speed.
On the left side of the above dialog is the "Max Payload Size" popup menu. To get maximum performance on your QuickSilver or later model, select this menu and choose the "2048 Bytes" item.
Click the "Done" button, quit HDST, and restart your computer. You should immediately test the drive's new setting BEFORE you trust it with your important data. Please see Chapter 7 of the "HDST User's Guide" for instructions on using Intech's Integrity application to test your new settings.
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The setting change:
The top group of settings is called "SCSI Manager 4.3 Options." The first check box
is labeled "Disable Wide Transfers." This will be checked by default. This item is
checked by default because of the numerous problems we have encountered running wide (16 bit)
transfers with certain PCI SCSI HBA's. If you have an Adaptec or Apple Computer wide HBA,
you can uncheck this button with confidence, as long as you're not running a mixture
of wide and narrow devices on the same bus. For all other HBA's, you'll need to
try it and test it. If it works and the drive is fast enough, you will see a dramatic
improvement in performance.
Click the "Done" button, quit HDST, and restart your computer. You should immediately test the drive's new setting BEFORE you trust it with your important data. Please see Chapter 7 of the "HDST User's Guide" for instructions on using Intech's Integrity application to test your new settings.