It could also just be your drive controller is not capable to sending data fast enough. I had similar problems when I had the LG hooked up to a PCI IDE controller.. Promise 100, since the drive itself wont go faster than DMA 33, you would think there would not be a problem. But there is. Hooking it up to my motherboard IDE controller and it cut down the recording time by half. In fact with the same controller and my older Intel mother board, I got faster recording speeds.
One of the weird things in this is, with my liteon cd writer it would go from red to yellow indicating a buffer under run, But the disk would get recorded at the speed specified, But the LG dont have such a light, But you can hear the drive slowing down. IE it records slower because it cant get data fast enough. Maybe because slower burn is a better burn??
@ 52X, the LG burns a disk in less than 2.20.. Even on media rated at only 32-40-48X.. I have some media I got 5 years ago (those weird multi colored ones) which were only rated 16x and it still only takes 2 mins on those.