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General discussion

DMA vs PIO settings

My PC is slow, will changing to DMA improve performance? When I view the settings, it is DMA if available, and transfer is set to PIO for both ide controllers? I have tried changing the settings, but I do not have an option to change tranfer mode to DMA.

Below is some system info. Thanks for your help.

Motherboard is ABIT NV-7 133R
Operating System System Model
Windows XP Professional Service Pack 2 (build 2600) Enclosure Type: Desktop
Processor a Main Circuit Board b
1.47 gigahertz AMD Athlon XP
128 kilobyte primary memory cache
256 kilobyte secondary memory cache Board: nVidia-nForce
Bus Clock: 133 megahertz
BIOS: Phoenix Technologies, LTD 6.00 PG 03/07/2002
Drives Memory Modules c,d
120.05 Gigabytes Usable Hard Drive Capacity
111.77 Gigabytes Hard Drive Free Space

3.5'' format removeable media [Floppy drive]

Generic STORAGE DEVICE USB Device [Hard drive] -- drive 2
MAXTOR 6L040J2 [Hard drive] (40.03 GB) -- drive 1, s/n 662221948355, rev A93.0500, SMART Status: Healthy
WDC WD800JB-00CRA1 [Hard drive] (80.03 GB) -- drive 0, s/n WD-WMA8E2361627, rev 17.07W17, SMART Status: Healthy 640 Megabytes Installed Memory

Slot 'A0' has 256 MB
Slot 'A1' has 256 MB
Slot 'A2' has 128 MB
Local Drive Volumes

c: (NTFS on drive 0) 69.54 GB 62.69 GB free
d: (NTFS on drive 1) 40.03 GB 38.67 GB free
e: (NTFS on drive 0) 10.49 GB 10.41 GB free

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DMA vs PIO settings

In reply to: DMA vs PIO settings

In Win XP, there is no tick box to select DMA like in earlier versions. You just make sure it says 'DMA if available' and Windows does the rest. If DMA is not available Windows will set the mode to PIO automatically when you re-boot.
Now, there are two possible reasons why DMA is not available on your two IDE channels:

1. The disks are not compatible with DMA mode. This is very unlikely since such disks would have to be very old ones - and yours are probably not very old.

2. The IDE data cable is only the old '40-wire' type.
Changing it to an 80-wire IDE cable may do the trick. These have the same type of connectors as the 40-wire type, but each of the three connectors are coloured differently -- Blue, Black, and Grey. Just make sure you fit the blue connector to the mobo, the other end (black) to the master disk, and the middle connector (grey) to the slave disk. Then boot up and check device manager again to see if DMA is now enabled on the primary channel of the IDE controller.

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DMA vs PIO settings

In reply to: DMA vs PIO settings

Thanks for comments.

The PC was built in 2002 and has rounded cables, how do I check for 40pin vs 80pin?

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DMA vs PIO settings

In reply to: DMA vs PIO settings

I switched the round cables to flat 80 pin and still cannot change settings.

Trying to "del" in boot but pc not allowing me to access.

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(NT) (NT) What about motherboard drivers?

In reply to: DMA vs PIO settings

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I'm confused

In reply to: DMA vs PIO settings

Not sure what you got and where - forget about the USB drives - We need to know what is on the IDE primary/secondary master/slave - are you talking about all drives eg Hard disks and CDROM showing PIO???

As it has been suggested by others your cable and drivers can cause the problem - however, an incorrect installation or driver can also cause the problem - as a last resort microsoft recommend deleting the IDE driver and letting the system find it again.
Try this with the secondary IDE in device manager and reboot - the system should find the drives again and reinstall drivers (hopefully the right ones)
Microsoft recommends not doing this on the drive whicg your system resides but gives no reason from memory, but I have read from others that it works. Anyway try deleting the 2nd IDE and see if it does the trick - it did for me a while back.

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One other thing

In reply to: I'm confused

check that your bios has UDMA set

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(NT) (NT) Thanks, finally got into BIOS and able to change ide to

In reply to: One other thing

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(NT) (NT) change IED to.....what? - you going to share it with us
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DMA vs PIO Settings

In reply to: (NT) change IED to.....what? - you going to share it with us

I was able to change ide settings to auto in the BIOS. I could not get the DEL key to boot to BIOS as my keyboard is USB (duh, I forgot I had USB keyboard)

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"My PC is slow"

In reply to: DMA vs PIO settings

Where and when?


1. The article [Q811493] explains that you may experience slower computer performance after you install the 811493 (MS03-013) security update package on a computer that is running WinXP Service Pack 1 (SP1), or after you upgrade to SP1 on a Windows XP-based computer on which the 811493 security update was previously installed, and that the patch can be removed if installed. This problem may be more likely to occur if you use some features of some third-party programs such as antivirus programs. For example, this problem may occur if your antivirus program is configured to scan all files when you open (or you run) them. This is sometimes called "real-time" scanning.

2. "Computer Speed and Performance May Decrease (Q3104119)."

3. The article [Q812337] explains that a Hewlett-Packard (HP) Pavilion computer may run very slowly after installing the HP software update for the Universal Serial Bus (USB) multimedia keyboard, and you may also notice the CPU is running at 100%, with the Kbd.exe file taking up over 90% of the resources.

4. File transfers and printing done by means of infrared data association (IrDA) may be slow and a print job may time out and stop printing, or it may take an extremely long time to complete, [Q823979].

5. The article [Q810063] explains the situation that when using a USB keyboard and mouse connected to a USB 2.0 Controller, they are slow to respond after a hibernation event.


1. Change DMA transfer mode to PIO mode, also explained in #8d below, (click Start, Control Panel, double-click System (if you do not see it, switch to Classic View in the left pane), click the Hardware tab, and then click Device Manager). Alternatively, right-click the My Computer icon on the desktop and then click Properties.

a. Double-click IDE ATA/ATAPI controllers, double-click Secondary IDE Channel, and then click the Advanced Settings tab -- if you do not see it, DMA transfer mode options are not available for SCSI drives.

b. Under Device 0 (most likely your hard disk drive and should not be changed), select PIO only in the Transfer Mode box. If you have more than one CD or DVD drive, also select it again under Device 1. If Current Transfer Mode under Device 0 or under Device 1 states Not Applicable, that device is not in use. Change only the devices that do not state such. If they do, your CD or DVD drive is on the Primary IDE Channel (double-click Primary IDE Channel and on the Advanced Settings tab under Device 1, select DMA if available in the Transfer Mode box).

c. Click OK, and then restart the computer.

3. The article [Q310751] states that when attempting to configure the direct memory access and programmed input/output (DMA/PIO) settings for a device on a WinXP-based computer, the settings may not be found in the Properties dialog box and occurs because the DMA/PIO settings are configured for each controller instead of for each device. Depending on the option set for Transfer Mode, simply changing it from PIO Only to DMA if available and then back again may cure certain anomalies.

4. The article [Q304853] states that when upgrading a Sony computer from WinME to WinXP HE, the startup sound may plays irregularly when the computer starts, and can occur because direct memory access (DMA) is not the default setting for integrated device electronics (IDE) devices.

5. The article [Q327805] states that after installing WinXP SP1, ATA-133 (Ultra DMA Mode 6) devices are not enabled even though SP1 supports it. Since Ultra DMA Mode 6 devices were not supported prior to SP1, they are not installed/reinstalled in the process.

6. The article [Q310592] describes the subkeys contained in HKEY_LOCAL_MACHINE\Enum for the specific hardware components entries for Plug and Play components of the BIOS (this includes timers, controllers, and direct memory access [DMA] chips). Each BIOS subkey starts with the string *PNP and is followed by a four-digit number that represents classes by which the components are grouped.

7. Hard disk performance may be reduced since the Windows IDE/ATAPI port driver ( reduces the communications speed (the transfer mode) from the highest Direct Memory Access (DMA) mode to the lower DMA modes after a cumulative total of six time-out or cyclical redundancy check (CRC) errors occur. If the driver continues to receive time-out or CRC errors, the driver eventually reduces the transfer mode to the slowest ''PIO Mode.'' Use the Advanced Settings tab in Device Manager to view the properties of the IDE channel to which the drive is connected. READ and apply any of the resolutions for this symptom as explained in the article ''IDE ATA and ATAPI disks use PIO mode after multiple time-out or CRC errors occur (Q817472).''

8. Supplemental reading:

a. ''DMA Mode for ATA/ATAPI Devices in Windows XP.''

b. ''Instructions for enabling DMA in Windows XP.''

c. ''HOW TO: Manage Devices in Windows XP (Q283658).''

d. ''Abit Hot Rod DMA 366 IDE Expansion Adapter Does Not Work After Windows XP Upgrade (Q305028).''

e. ''HOW TO: Configure Devices By Using Device Manager in Windows XP (Q307970).''

f. ''Description of Ultra DMA (Q308541).''

g. ''Explanation of Error Codes Generated by Device Manager (Q310123).''

h. ''Programming of Transfer Mode Speed Is Not Supported by Atapi.sys When You Hot or Warm Swap Drives (Q323760).''

h. The Black Max PC site concerning ''DMA XP/2000.''

9. As a last resort and your understanding of the instructions presented in ''8h'' above, in Safe Mode, start removing the device(s) in question, and then reboot the computer to see if Windows correctly identifies the device again with appropriate driver that allows the switch to take place -- perhaps a driver you have installed is the culprit.

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(NT) (NT) Thanks Cursorcowboy, will defintely read these articles

In reply to: "My PC is slow"

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PIO to DMA problem

In reply to: "My PC is slow"

I installed SP2 on my main disk and I found that DMA is not installed as it was under SP1.
I did all sort of things to get it working without luck. Burning a DVD is extremely slow now.
1) I changed to DMA if available
2) I uninstalled-reinstalled secondary channel (Adv. conf tab is missing after this)
3) I uninstalled Intel ultra ata controlled but I have to return to 'previous working conf' in windows startup.
4) I deleted ''HKEY_LOCAL_MACHINE \ SYSTEM \ CurrentControlSet \ Control \ Class \ {4D36E96A-E325-11CE-BFC1-08002BE10318} ''MasterIdDataChecksum'' s describe at
5) I reinstalled SP2 from CD (update install).

Microsoft is the driver supplier on both primary and secondary channels.
There is Intel 82801DB Ultra ATA Controller under ide ATA/atapi controllers

I did a clean(new) SP2 install on my third disk and it recognizes DMA ultra modes for all devices as it used in SP1.

So, my next question are: how may I correct this issue without having to make a clean install on my main installation?
If it would not possible, how may I backup-restore all (I mean, ALL) settings and data without altering DMA settings?

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PIO to DMA Problem

In reply to: PIO to DMA problem

Hi dstonek:

I went to BIOS setup, periperhals and set ide controllers to auto. I check that burners and dvd/cd were set to master and/or select and I was set to go.

You don't know what you are "missing" until you find it!

Good luck

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In reply to: PIO to DMA Problem

I know what I am missing: my PATIENCE
I've been using Windows from 3.0 version around 18 years ago and always (I mean ALWAYS) am having problems updating Windows and working on Microsoft enviroment. I am proud of myself to decide to work seriously when in 1994 I purchsed the first Apple Power PC and its consecutive hard and soft updates and upgrades.
That were times I had to have Mac and Win because our clients. I am not sure I have to keep this Win computer.
Thanks anyway.

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