Tweaking WinMe: Enabling DMA
Enabling Direct Memory Access for you hard drive is one of the best tweaks you can do for any computer, because the speed gains are astronomical. Enabling DMA, which allows data to be transmitted directly between the RAM and the Hard drive without the direct intervention of the CPU can increase the performance of the hard drive by up to fifty percent, and increasing the responsiveness of your system by a significant amount. This extra speed comes from the two main features of DMA - not having to wait for the CPU, and an overall faster burst rate (or transfer speed). The title of this article says that this is a tweak for Windows Me, but it can be applied to any version of Windows 95 or 98.
Before you decide to follow through with this tweak, be sure to check to make sure that your hard drive is capable of using DMA. If your computer was built within the last four or five years, you have nothing to worry about, but if your computer is older, you may wish to check with the manufacturer to make sure that the installed hard drive supports DMA.
To begin, start by going into the Control Panel and
starting the Device Manager in the System applet. Find the icon for the hard
drive for which you want to enable DMA and go into its properties menu. From
there, check the DMA tick box. Once you close out the Device Manager, it will
ask you if you wish to restart your computer. Say no, because there is something
else that must be done to properly enable DMA. Use the find files and folders
command to find the files Mshdc.inf and DISKDRV.INF , both of which you should be able to find within the windows/inf subdirectory. Depending on how your system is configured, you may also have a backup directory which includes these files - feel free to modify them as well.
Open Mshdc.inf in notepad and find the sub-header [ESDI_AddReg], under which you will need to check for the following lines:
If they aren't there, add them and then save the file.
Next, open up Diskdrv.inf in notepad and find the [DiskReg]
sub-header. Underneath it, look for the same four lines, add them if necessary, and save the file. If these lines were already present in both of the files, your computer will enable DMA after your next reboot. However, if you had to manually add the lines, return to the Device Manager and delete the hard drive listings (the same ones which you checked the tick box in earlier) to force the computer to reload the drivers for your hard disks. Once you've done that, restart your computer.
After the computer reboots, the Add New Hardware wizard should pop up to reinstall the hard drives. Select the 'choose from the compatible drivers list' option to see the driver list. The driver list should have your newly modified hard disk drivers listed, and they should be accompanied by the date of the modification. Install these drivers. Then, for the last time, enter the device manager and make sure that DMA is enabled (if it isn't, check the DMA tick box and reboot). Congratulations, you've just enabled DMA on your computer!