I read in an review of the BenQ DW1650 written by a private person’s experience with the drive and he claimed that burning in 8x and above on this drive produced fewer errors than burning it in 4x and 2,4x, without any references to any perticular brand. I’ve always thought that the lower the burning speed, the better the quality, no matter what dvd brand you used. I think I even read in a burning guide once that you should burn your video dvd’s in max 4x for quality reasons. Anyone had any experience with 4x vs 8x burns on the BenQ DW1650 ? Is it true that higher speeds can give better burn quality ?
The myth about burning slower for quality is , generally, just that - a myth.
It’s mostly recommended here that you burn at the rated speed of the media, with the possible exception of 16x media which can benefit , on some burners, with being burned at 12x.
With a drive like a Benq which does Disc Quality scanning you shoudl start with burning at the rated speed & do DQ scans & compare to those that might have been burned at a slower speed.
Some media like Taiyo Yuden T02 (+R 8x) burn extremely well at 12X & 16X.
If its a myth, why does my Harman Kardon DVD 25 only play disc’s burned at 4x correctly. All burns I’ve done at speeds 8x and above does not function correctly in the Harman Kardon player. The problem is that when you play the film burned at 8x and above often suddenly skips 15-30 seconds forward in the movie. This happens several times during the movie. But all dvd’s burned at 4x function properly on this player, even when the quality scans in Nero CD/DVD Speed is better on the ones burned at 8x and above than the one burned at 4x.
It is because it often happens that high quality devices have more sensitive laser lanses and in result do not work as universally as the cheap one. In my opinion for example sony DVD’s, CD players are not worth buying, because their laser leanses are so sensitive that they often do not want to read self-burnt doscs. I’ve had a sony cd player and a few of my friends had either, in all cases there were problems with lasers.
What media, what burner? Don’t compare pears and apples. 
With 8X rated media of average quality, in a 8X burner, you can get better results @4X. Just an example to make my point that anecdotic results don’t allow to make general conclusions. “Don’t pee on my leg and say it’s raining”.
I burn all my discs at rated speed, mostly minimum @8X, and they play in ALL, I say ALL the standalone recorders I’ve put them into.
About the 1650, I can confirm that according to PIE/PIF/jitter testing, most media burn better @8X and 12@ than @4X. As for 2.4X, it should be used for DL media only.
What on earth are you talking about? This sounds like utter nonsense to me.
I’ve tried Verbatim MCC 004 burned at 8x on my Philips DVR1648 and one burned on my BenQ 1650 at 12x (got a really good quality score on that one, think it was 98 or 99). I also tried a SONY D11 burned at 8x on the BenQ 1650 and a TDK (TDK 003) burned at 16x, 12x and one at 8x on the BenQ. All of them “skipped” when playing at the Harman Kardon like I described. I burned the same movies at 4x at the 1648 (using Verbatim,TDK (burned on the BenQ), and Sony) and they worked like a charm. I have to add that I have a Philips DVP5500S standalone player and that player plays the disc’s burned at higher speed without problems. But since I prefer the picture quality on the Harman Kardon a bit over the picture quality on the Philips, I prefer that all my movies can be played on both players.
I can also add that I have a Plextor CD burner (40x12x40A I think) with a maximum burn speed at 40x, but Plextor has set a 24x limit for burning audio cd’s because the claim that burning audio cd’s at higher rates will create burns of inferior quality.
Then do what works for you 
…
For me your issue is a mistery. 
Unless you Harman Kardon is extremely sensitive to jitter. 4X burns can actually produce lower jitter… but gee, it would mean that this player is veeeeeery picky! 
Fortunately, none of my customers seem to have such a picky player… never had a complaint with discs burnt at rated speed! 
As they say :
Do what works for you
I mean if you like your HK and it works only with discs burnt @ 2X , then burn at 2X , even it takes longer time , at least you will have the discs for some years to come.
I have a question regarding that matter too and find this a good opportunity.
My brother lives in the United States and a friend of his gave him a crappy DVD/VHS compo player called “INSIGNIA IS-DVD 040924” , he wants me to burn him some DVD-Video discs and send them to him .
I have the Benq 1640 drive and some Benq 8X DVD+R Daxon AZ2 and Sony MIJ D21 discs , I will booktype the discs to DVD-ROM for better compatability , but wonder what speed should I burn at .
I don’t want to send them to him from here Egypt across the ocean to the US , just to discover that his player won’t play them 
I’ll attest to the Benq 1650 having better scans at 8x and 12x speed,using quality media. Same results with my 1640. With my benq drives and my quality media,slow burning produces way too many crc errors.
Example: MCC-004. I use my normal process of ripping with dvd shrink and autoburn with nero 6.0.0.21b. When i’d go to sleep,leave for work,or busy-I’d set it up to burn at 2.4x and auto shutdown. Well,a few weeks later,I went to re-rip some backups. Bam-Crc errors.They still played ok,just wouldn’t re-rip. I narrowed it down to those 2.4x burns. I re-backed the originals again,using 4x. Verbatim 16x media were designed to be burned faster,not slower. On another brand,results may be the opposite.
Beware of 2.4x burning with MCC-004 media if using a benq 1640/1650. Anyone burning that slow with a benq,try re-ripping one of those backups and see if you can get it back onto your harddrive without a crc error.That’s a pretty easy test to see how actually good they are. Scans are ok,but a backup disc that I can’t re-rip-Is of no use to me.
My latest version of Nero 6.6.0.14 came with my 1650 a couple months ago,via canada.My old version didn’t have nero’s disc quality scan program-grayed out. This newer oem disc does. For MCC-004 media,my benqs scan best at 8x. My 12x tests scanned a hair less,but way better than the 4x tests.
Got a Q 1640 or 1650 and using quality MCC/Hitachi/Ritek-R03/or Taiyo yuden?definitely 8x!
Then there’s still the typical picky player.They can do some weird things. I burn according to how may scans give me the fewest errors and my stand alone players and pc drives playability.
In general Metal Azo dyed disc burn better at high speed, posible 12-16X.
Jitter rating as i know is depend upon the scan speed, scaning at 8X obviously get higher jitters than when scanned at 4X.