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Thread ID: 33502 2003-05-17 22:02:00 CPU 100% while reading CDs heni72847 (1166) Press F1
Post ID Timestamp Content User
145289 2003-05-17 22:02:00 i've got a JLMS-XJ-HD165H liteon dvd-rom
for some reason everytime when i copy big files from cd
eg. 180Mb

it uses up all the cpu and it feels like the computer is going to crash
even the mouse get's laggy
then after copying the file
everything's back to normal

also when i copy big files for too long
my modem stops working
it won't download or upload



is there a way so when i access the cd
it doesn't take up so much cpu?
heni72847 (1166)
145290 2003-05-18 00:52:00 sounds like you've got PIO access going...

first of all what mobo have you got? It doesnt really matter BUT you can get a large improvement by installing the latest motherboard drivers... knowing what mobo you've got would help me/others with providing you with links to the drivers you need...

secondly, to fix this problem you'll need to enable DMA on your dvdrom.

How to do this depends on what version of windows you have... if you have win9x you'll have to open up device manager (right click on "my computer" left click on "properties" and then click the hardware tab - if i recall correctly), then double click on the rom drive that is affected and in the advanced properties tab select the DMA checkbox. restart and you're away laughing.

However if you are using 2k/xp, you'll have to open up device manager (right click on "my computer" left click on "properties" and then click the hardware tab, and then the device manager button) *breathes in* then expand the IDE ata/atapi controllers, select the controller that your dvdrom is on... normally secondary controller and go to the properties of that controller. Then click on the Advanced Settings tab and change all instances of "PIO only" to "DMA if available" Restart and you'll be away laughing...

For 2k/xp, look here (www.g33kflat.skankyflat.net) to see something along the lines of what you want to see
whetu (237)
145291 2003-05-18 01:24:00 um.. i see....
so what is the difference between PIO and DMA?
why would PIO use so much cpu?
heni72847 (1166)
145292 2003-05-18 01:30:00 Under PIO all the work is done by the CPU
Under DMA (Direct Memory Access) its direct, and allows the CPU to get on with other tasks
godfather (25)
145293 2003-05-18 01:56:00 to define a bit more on what godfather has said..

with PIO, the cpu does all the talking between the drive and the rest of the computer. This puts an extremely high load on the major backbones of communication around the motherboard, and traditionally the major backbone is the PCI bus, which explains why your connection gets knocked off.. the high load on the PCI bus is too much for your modem, errors occur and the standard action is to disconnect.

Whereas with DMA, a small "cpu" built into the drive itself controls all the talking between the drive and the rest of the cpu... this takes a load off the cpu and the PCI bus

speaking on a basic level that is...
whetu (237)
145294 2003-05-18 04:23:00 thanx
that totally explains it
heni72847 (1166)
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