Plextor 40X in PIO mode?

All of a sudden my plextor is in pio mode…it was burning major slow and so many buffer underruns. So i checked and its in pio mode and when i switch it to udma mode it doesn’t do anything. It used to be in DMA mode but I don’t know what happened.


Did you install WinXP Service Pack 1??

Alot of people have notice this happen once they have applied SP1.

Try using System Restore.

Good Luck!!


This happens for both of my VIA chipset pcs, one running under WinXP Home the other Pro, and here’s how I fix the problem. Go to Device Manager, go to IDE ATA/ATAPI Controllers, then select VIA Bus Master IDE Controller. Right click on it and selector uninstall, or just press delete on your keyboard. Confirm it and restart, if it is still on PIO set it to use DMA and restart. Hope this solves your problem.

BTW, where do you go to download WinXP’s Service Pack 1?


Im running windows xp and have plexie 40x and had the problem all of the sudden running in pio mode and not dma.I downloaded aspi drivers to install,talked to plextor but come to find out when i did a windows update which i believe was a recommened update not a critical update i lost my dma.I had backups did a restore befor the updates and no problems so be careful what you download from micr$oft.It show billy bob and his crew are a bunch of dumbasses.Hope this helps bud.

I used dfourthhorseman’s advice and it worked…Thanx

No problem. Since you successfully used my advice, I’m guessin you have a VIA chipset, if so you should update it to the latest version, it just came out VIA 4-in-1 Driver ver. 4.40. Go to to download it.


let me buy dfourthhorseman a large drink . had the same problem as frubsen, did what dfourthhorseman advised , bingo all working fine now , cheers m8.

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