Scan in 1693 looks bunk in 1635 and vice versa

Hello,

I’ve learned a LOT from reading cdfreaks and I want to thank everyone for their time and patience with us noobs. :wink:

Discs burned and scanned in my 1693 look wonderful. However if you scan the same disc in the 1635 it still looks good but worse.

Exactly the same for the 1635. Burn in 1635, scan in 1635 looks great, scan in 1693 - it looks good but not great.

Mostly there are areas on EACH disc that there are LARGE [in the thousands] of PIFs when scanned in the OTHER drive.

Is this the case with any two given drives or just something with these two particular drives?

I of course can provide scans if necessary.

If it makes a diff, the 1635 is in fact the Office Max digital max 5s163.

Thanks,
Chad

I’ve had a few Liteon drives in the past and found this as well. Over time, I have stopped trusting their scan results. I contacted Liteon numerous times about these types of issues (and others) but they just kept telling me my drives were defective and misc. BS until I got fed up with them, took a haitus from their products and then tried another a while later and was still underwhelmed (1633S). My Samsung drives which use the same Mediatek chipset as your Liteon drives often shows scan results which are nothing like the BenQ scans. Some make sense, others are bagged on my Benq’s but claim to be insanely good on the Samsung itself. In general, I find their results to be optimistic if they actually provide accurate data.

On the other hand, I have had four BenQ’s (currently a DW1620, DW1640 and DW1655) and they all produce near-identical and repeatable scanning results compared to each other. The BenQ’s provide more scanning info as well. I have a Plextor PX-716A as well which has similar but proprietary features and I have been disappointed by the quality, performance, and reliability of it. It’s the most expensive 12x writer you can buy! :wink:

When I first heard about BenQ supporting these advanced scanning functions I almost laughed, but after owning a few of their recent products I’ve found they are a far different company than they were in the past. If you want a fast, reliable and full featured scanner for an excellent price, buy a BenQ (and you won’t even need to find doctored firmware to make it work right). Just my opinion…

Signed,
ex-Liteon man

I also found ridiculous KProbe traits like getting better quality readings at higher scanning speeds than lower ones. Results like this just defy common sense, and caused me to lose faith in the integrity of the results. As well, sometimes the drives would lose sync with themselves during a scan and just keep on spinning with no results being produced, etc. My BenQ’s have never had these types of problems.

it could be sampling per clock cycle instead of sampling per x sectors which would mean that there are fewer samples; or maybe at high speeds the chipset can’t handle reporting that fast. who knows

There are at least two factors pulling the scanning results in opposite directions at high speed and low speed:

Modern drives are designed to read (and burn) at high speed, and this means that they often will not read as well if you reduce the reading speed too much. Thus you can get worse quality scans at the lower reading speeds; e.g. lower than 8x or 12x.

On the other hand it is more difficult to read a disc that is spinning at high speed due to vibrations, tracking problems, focus problems, beta values that stray too far from zero, high jitter, etc.

Most of the time the second effect seems to be dominant and you get better scans at low speeds, but at other times, especially on high quality discs with high quality burns, the second effect is less dominant and you get better scans at high speed.