Are you inserting the blank into the drive before choosing the burn speed? Have you checked to see that DMA is enabled?
where do you check dma? When I first installed it it was burnning at 8 but I had to do a restore. I installed it again and thats when it started to only burn at 2.5. DMA where?
May need a firmware update. You can check that in decrypter - go to tools>drive>check for firmware update. A pop will display the version you have then take you to the firmware page to see if there is a later version. What media are you using - can be another cuase.