'Bunch of me

Experiencing violent upsurge in the CPU usage characteristics of your PC ? Browsers, word processors and other everyday applications/softwares taking days to start up or respond ? Chances are, you haven’t unleashed a special, ‘superpower’ tucked hidden in the architecture of your hard disk drive. Its called the UDMA (* U stands for ‘ultra’, how trite, right?) mode. It should’ve been the default only option automatically selected by Windows XP during a fresh installation due to its vast superiority in direct memory access & bus speed support of over 16 Mbit/sec, but unfortunately they had to include an exception. Whenever you install a Windows OS and it decides (with great margin of error) that your ATAPI drive is not suitable for UDMA (when in actuality every HDD built after 2002 is), the OS would revert back to the ancient PIO ( Programmed Input / Output ) mode . Now, there’s nothing wrong with PIO except the fact that its slow as a slumdog trillionaire (not to be mistaken with an analogous movie title) and as mr duck puts it “Nothing built this century should be using PIO.”

Anyway, if you are experiencing mysterious cpu-hogups download and run Process Explorer, a free diagnostic tool from Microsoft SysInternals, which happens to be a much more potent tool than the windows task manager (what are the odds of that, right?…plenty). After running process-exp, look for a process called ‘hardware interrupts’ on the left hand bar of the screen. If the process is present on the 1st column and eating up a lot of memory (see the 3rd column titled ‘cpu’), then ‘presto’- thats your problem .

There are some registry hacks available on other sites that requires you to delete a few key registry entries, but my personal recommendation is that its better not to mess with the registry unless absolutely necessary . The registry is a fragile thing and can break down easily. So here’s a totally safe way to do the good deed:-

1) Go to device manager (right click on the My computer icon> Properties > Hardware.

2) Expand the IDE ATA/ATAPI controller section ( press the + )

3) Right click on the Primary IDE channel (if you want to enable UDMA in your secondary drive too, you can repeat this process) and go to Properties > Advanced Setting

4) Now here’s the trick, regardless of what it says in the “Transfer Mode” section (even if “DMA if available” option is displayed ), you’ll have to manually reset and force XP to use UDMA. To do that, first select PIO only in the box for transfer mode for both Device 0 and Device 1. Then confirm by pressing the ok button

5) Then go back to the device manager screen again, right click on Primary IDE channel as before and go to advanced setting once again. Only this time, select “DMA if available” in both transfer mode boxes. Confirm your selection by pressing ok. You’ll see “Ultra DMA Mode 2” appearing in the current transfer mode box.

6) Restart and bask in the glory of your faster, more responsive system :)

This hack was extracted from an official Microsoft bulletin addressing the PIO/DMA issue (or as it is known in popular folklores, the “XP DMA BUG”)

Tags :Windows,Microsoft,XP,DMA,UDMA,PIO,HDD,Hack,Process,Explorer,performance