I have just purchased two Optiarc 7240s drives. I have had a big problem so far with dual burns. When using Nero or two instances of IMG Burn, the device buffers for both drives alternate rapidly. The fastest I can get them to burn is 4x when i am attempting 8x.
Media = verbatim dvd+r
Motherboard = ASUS M4A785TD-V EVO
Processor = AMD Phenom II X3 720 2.8GHz
Memory = G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800)
OS = windows 7 64bit
Hard Drive = Western Digital Caviar Black WD1001FALS 1TB (the hard drive buffers are always 100% full... it's a device buffer issue)