I want to say any Samsung SH-224** model, where ** is AB, BB, CB, DB, or FB. The two character combo just denotes hardware revisions, but reading performance should be similar.
And as for the LiteOn... you'll find the iHAS*24 drives, where * will be some number that doesn't matter (only refers to whether the drive has select extra labeling features & such, which you can determine from the specs on the box/from the site you order from).
Now, some of the LiteOn drives are very similar to your current Optiarc (for the sake of the conversation, they are the same as your Optiarc). These hardware revisions can only be discerend by looking at the drive label/having the drive connected to your comouter, or by knowing the various packaging codes LiteOn uses for each hardware revision. But I personally don't know the packaging codes, and most places don't outright tell you the hardware revisions you would get. Worrying about that would be a hassle.
That said, it would still be pretty easy for you to just pick up a LiteOn off the shelf and still get the performance you need. But I would try to find a Samsung drive first and see how that works.
(for curiosity's sake, your goal in getting a LiteOn drive would be to get an iHAS*24 A, B, C, D, or E, and avoiding the iHAS*24 W, X, and Y. The extra letters of the alphabet determine the hardware revision. W through Y are the drives that are relatives of your current Optiarc, while A through E are more like LiteOn's original drives which would more than have the performance you desire. That's why I say it's probably easy to go for a Samsung drive instead.)