[ The PC Guide | Troubleshooting and Repair Guide | The
Troubleshooting Expert | Troubleshooting Specific Components
| Troubleshooting Hard Disk Drives | Performance
I added a new, modern hard disk to my older system, but it is performing slower than it
Explanation: You upgraded or replaced your hard disk, but it is still performing at
a speed comparable to your older drive. The transfer rate performance is not quite as good
as you were expecting, or benchmarks are lower than what others are getting for the drive.
Diagnosis: As discussed in detail in this Reference Guide section on hard disk
performance, the performance level of a hard disk is dependent on many different
factors. Some of these are a function of the hard disk itself, but many are a function of
the other parts of the system. Most hard disk benchmarks in fact are influenced by the
speed of the chipset, processor, memory and other components. Also, putting a new hard
disk into an old motherboard can greatly limit its performance because the interface may
not be capable of running at the higher modes that are required for peak performance.
Remember to check out this section in the
Optimization Guide on hard disk performance.
- Be careful about how you interpret
benchmarks. In a nutshell, many benchmarks are deceiving and may give you an incorrect
picture of how your hardware is really working.
- Running a new hard disk on a system that uses ISA-based hard disk I/O will severely
limit performance. I would strongly recommend a motherboard upgrade for any system that
does not have at least a VESA local bus hard disk controller.
- Many older systems do not support the faster PIO modes required for high-speed transfers
to and from modern hard disks. In particular, if your system uses a 486 class motherboard
and an expansion-slot hard disk controller, it may only support the slower PIO modes. In
this case, the peak transfer rate of the hard disk will be reduced. You may want to
upgrade to a newer controller or motherboard.
- Some motherboards support higher PIO modes on their primary IDE channel than they do on
their secondary channel. If the new drive is on the secondary channel you may see a speed
increase by moving it to the primary. Consult your motherboard documentation.
- Motherboards that do not support independent
drive timing will slow down a faster disk if it is shared master/slave on a channel
with an older disk. You may want to try the disk on a separate channel.
- Make sure that the new hard disk is properly set up in the BIOS. Some systems may not
set the disk to the optimum performance
settings automatically, even when they autodetect a drive. You want to make sure that
the PIO mode is set to the correct value, and also that block mode and 32-bit transfers
are enabled (if the drive supports them and if they don't create any problems.)
- Hard disks will generally just perform slowly on an older system overall. The hard
disk's transfers are affected a great deal by the speed of the CPU and the motherboard,
and a new, fast 2 GB drive is going to run much more slowly on a 486DX2-66 than it is on a
Pentium 200, all else being equal.
Home - Search
- Topics - Up