When The Hard Drive Slows Down The System

It can happen to everyone in certain situations to notice a very slow system where you feel the hard disk that works Very long opening operations with consequent deterioration of performance… But what does it depend on? Maybe it’s the hard drive that doesn’t use the right technology … let’s understand more.


When the hard drive slows down the system


It can happen to everyone in certain situations to notice a very slow system where you feel the hard disk that works…. Very long opening operations with consequent deterioration of performance.

This is what happened to me recently, a problem that led me to think of formatting everything thinking about an old and hopelessly slow system … and instead it was only a matter of resetting the primary hard disk so that it could use Ultra technology DMA, possibility lost as a result of who knows what mistake.


A little theory:


Hard disks (not very young) use ATA technology; these are devices connected to the motherboard through a flat cable (flat cables) with many small wires that are very different from the simple round cable of recent disks called SATA.

It is a standard interface for connecting storage devices such as hard drives and CDROMs / DVD-ROMs, also called with various abbreviations and acronyms such as IDE, EIDE, and ATAPI. Until 2004 it was the most widespread technology ever, replaced as mentioned by the more modern SATA. As a result, many people can have this type of device inside their PC.

For those who use this type of interface and peripherals, there are different data transfer modes, classified as PIO MODE, DMA mode, Ultra DMA.

Each modality allows different transfer rates, so making a hard disk work in one or the other mode greatly influences the performance of your machine, performances that can easily be increased tenfold and clearly visible to the eye!

Here are some examples of transfer modes and allowed speeds.



PIO mode            Bandwidth (Mb / s)

Mode 0                                 3.3

Mode 1                                 5.2

Mode 2                                 8.3

Mode 3                                11.1

Mode 4                                16.7


In this mode, important data transfers can quickly impose a large workload on the processor and slow down the whole system.


DMA mode         Bandwidth (Mb / s)

0 (Single word)                  2.1

1 (Single word)                  4.2

2 (Single word)                  8.3

0 (Multiword)                    4.2

1 (Multiword)                    13.3

2 (Multiword)                    16.7

The DMA (Direct Memory Access ) technique allows you to unlock the processor by directly accessing the memory of each peripheral.


Ultra DMS mode              Bandwidth (Mb / s)

UDMA 0                                           16.7

UDMA 1                                          25.0

UDMA 2 (Ultra-ATA / 33)              33.3

UDMA 3                                           44.4

UDMA 4 (Ultra-ATA / 66)              66.7

UDMA 5 (Ultra-ATA / 100)            100

UDMA 6 (Ultra-ATA / 133)            133


l ‘ Ultra DMA (sometimes signed UDMA ) has been designed in order to optimize to the maximum the ATA interface. The first idea of ‚Äč‚ÄčUltra DMA is to use the rising edges as well as the falling edges of the signal for bone transfers, a speed gain of 100% (with a band ranging from 16.6 Mb / s to 33.3 Mb / s).¬†


In addition, Ultra DMA introduces the use of CRC codes to detect transmission errors. Thus the different Ultra DMA modes define the data transfer rate. When an error is found (when the received CRC does not match the data) the transfer goes to a lower Ultra DMA mode, until there is no Ultra DMA. (source WIKIPEDIA)


The problem of the disk that works in low data transfer mode:


After this theoretical overview, where does the problem arise?

It seems that as a result of a series of errors in rapid succession of access and/or writing to the disk, some Windows systems automatically disable the faster data transfer mode in favor of the old PIO MODE, which as you see from the mirrors has a speed even 10 times lower than the Ultra DMA.

The same thing can happen if the BIOS default settings have been reloaded or for some reason, the BIOS items related to the use of the DMA mode have been altered.

Our disk in both cases would use transfer modes so obsolete as to have a large bottleneck for data transfer, with the inevitable consequence of a total slowdown in the performance of our machine.


What to do to resolve the situation?


Two simple things:


Access the BIOS (see the article Access the BIOS) and check whether the settings relating to the use of DMA are enabled or disabled. Once you have entered the BIOS, try pressing CTRL + F1 to enable the advanced settings of the BIOS itself… Depending on the BIOS in your possession, look for indications regarding the use of the DMA and if it is disabled, enable it or set the item as AUTO (or automatic selection). Once you have made the changes, exit the settings and start Windows.


Check the BIOS to enable the SMART option for the hard disk. Self-Monitoring, Analysis, and Reporting Technology, or SMART, is a monitoring system for hard drives, to detect and provide various reliability indicators, in the hope of anticipating malfunctions. 


Enabling it means making sure that in the event of a disk malfunction, a warning is issued to the user … this is because, despite the article highlighting a specific problem, we may also be faced with the unfortunate hypothesis in which the disk is physically damaged … SMART is not available in all PCs so look for it and in case activate it but not if you find nothing, do a reason …


Check the use of the primary and secondary IDE channels to see if they use the correct transfer mode. The two channels represent the two flat cables (see the start of the article) which from the motherboard allow the connection of 2 units each (a maximum of 4 normally). 


Generally, the operating system hard disk is located on CHANNEL IDE 1 set as MASTER (See article Connect a new EIDE hard disk) but we will control both channels. on Windows XP normally present on machines that use this type of peripheral and transfer mode, go to My Computer and click with the right mouse button to get the PROPERTIES option.


From the window that appears, we choose HARDWARE and then PERIPHERAL MANAGEMENT 

Select and expand the entry for IDE / ATA / ATAPI channels


Now let’s right-click on the first item, Primary IDE Channel and choose properties and then advanced settings. It is possible to note that there are two important items: Transfer mode, which must be set to “DMA if available” (if it is not so changing it) and Current transfer mode, which if correctly set should report a nice “Ultra mode DMA Mode x ” (where x goes from 1 to Vedic mirror at the beginning of the article). If you need to make any changes, do it and confirm.


Operate the same controls on the other channel in the same way. Once changes have been made, the system must be restarted to see if there have been any changes.


If changes are not possible, the alternative is to select the primary channel with the right button and choose UNINSTALL (see figure)


The same thing must be done for the secondary channel…. once these actions have been confirmed, the system itself will request a restart, after which the best settings for data transfer of those units will be re-identified…


the changes will be the consequence of the BIOS enablement of the items related to the DMA mode (if needed) and to the change of setting on the type of detection of the IDE channels just explained. Upon restart, the identification of the new channels will lead to another restart in order to exploit the peripherals seen in a “new” way. At the next restart, check the settings of the two channels and evaluate the overall speed of the PC in the normal operations of starting/closing or opening applications.


IMPORTANT!!! For operating systems later than Windows XP. The operations are absolutely identical in theory and in the settings to be set, only the way to reach the Device Management (or device management) and obviously some windows that can present additional options changes


I hope this article will be useful as it was for me to learn certain hardware knowledge that is not really my forte…



Hello Everyone This Side Zenith sez. By Profession, I'm an Engineer of Hardware and software. Regarding any issue, You Can Contact Me Directly.