Turning on IDE DMA in Win2000 (VIA chipset)

Qythyx

Member
Feb 6, 2000
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I have a Tyan Tiger 133 dual CPU MB that uses the VIA chipset. I was wondering how to turn on DMA for my IDE drives as this appears to not be on right now. I have installed the VIA 4in1 drivers.

This was a painful operation and caused Windows to crash and become corrupted so I'm not sure how correctly they are installed now. The Device Manager does say they are installed and being used but their settings has nothing regarding DMA.

The reason I thing DMA isn't on is because the system seems quite slow when it is doing heavy disk I/O (but low CPU) activities. The recent example was rippind a DVD to a VOB file. Task manager showed minimal CPU usage (~3%) but everything on the system was very slow. This is with Dual PIII 600s.

Any ideas would be appreciated.
 

joeyjojoe

Member
Dec 12, 2000
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i would think dma is on if there is little processor usage in read/write intensive situations. you can check by clicking on the primary disk controller in the device manager.
 

Wowbagger

Junior Member
Jan 4, 2001
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I know that if you have an ATA-100 drive on a VIA chipset (I have such a drive on an Epox 8kta2) Windows 2000 will run your drive in PIO mode, which could be the problem you describe.

When I first built this machine I ran into that problem, so just ran Win 98SE on it and the drive worked fine. But a Microsoft fix for this is supposed to be included in Service Pack 2...and there might be one out already since the last time I looked (2 months ago or so).
 

Joemonkey

Diamond Member
Mar 3, 2001
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you can already fix this in device manager.... instead of doing it per drive, you do it per IDE connection. go to device manager, click the + by the IDE ATA/ATAPI controllers, right click each controller, and pick properties. go to advanced settings, and change the Transfer Mode to DMA (if available) then reboot.
 

Qythyx

Member
Feb 6, 2000
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Because of the Via drivers, I don't have the 'primary disk controller' (or secondary) instead there are 2 VIA BM controllers (I'm not at my computer now and the names might be somewhat different). Anyway the properties for these don't have anything related to DMA.

BTW, I'm not using ATA-100. Just UDMA-66.