the UDMA mode decide to the IDE or SATA Device . this is Device report to BIOS , then our BIOS to set that . If your IDE HDD BIOS detect show UDMA2 , It only can run UDMA2 mode ,
I had tell you , the IDE UDMA mode decide from HDD or OS , It is no relate with mainboard . I have verify your question today , I have use NF94-270 mainboard + IDE HDD + IDE DVDROM , you can see attached picture , the IDE HDD work in UDMA5 mode , The IDE DVDROM work in UDMA4 mode .