I agree with all of you. Thanks for your comments. I was wrong about the cpu load in the tests, that in fact is very low, below 10% in all the cases. I initially took the data from cd/dvd speed, that seems not to be meaningful for this case.
I have just done three tests, for a typical 4.3 GB DVD video :
1) Rip from Liteon +RW 4x to HDD SATA RAID1 (mostly unfragmented). Result 8% cpu, 9 min, 8 MB/sec eq. to around 6x
2) HDD to LG H10N dvd +R 16x. Result 5% cpu, 6 min, 12 MB/s eq. to 9x
3) Disc to disc Liteon +RW to LG +R. 3% cpu load, 25 min, 3 MB/s, 2x
In the first two tests, the speed kept more or less constant. In the third, one, it began at 16x and 1 min later went to 2.3 - 2.7 oscillating for about 5 min to go slowly to almost 4x till the end.
Is interesting to point out that the disc to disc load is much lower than the sum of the two first, so the copy time gets higher. This indicates, I think, that cpu load is not the bottleneck, so the discussion about udma2 or udma4 is nonsense. Btw, both devices appear as UDMA2 in Windows Device Manager.
But 8 + 12 MB/s could give 20 MB/s average, that could lead to maybe more than 33 MB/s in bursts. So, if the bus were limited to atapi/33=udma2 (??) this could be the limiting factor. But I assume that the bus should be ata/66 or even ata/100 because the ribbon cable is 80-wire. And this made me think that maybe the failure could be at BIOS level. In fact I have level A01 (Dell 8400) and there is an A09 available. I tried to find a specification for the speed of bus or devices in BIOS and I could not find it. So I will try to flash the latest BIOS in the next days.
When I was thinking that udma4 could be good, I saw a DVD reader Asus DVD-E616A3 supporting udma/100 (udma5?) for just 17 â‚¬ that could serve as a replacement for my old Liteon. And I still keep on thinking that it could support a higher transfer rate (assumed I would flash the new Dell BIOS and there were no restrictions from the IDE bus side, if this would be the problem). Any idea on this?
Here are the results from cd/dvd speed reading a 4.38 GB dvd video:
Nero CD Speed Test results
Operating System Windows XP Home Edition (5.01.2600 Service Pack 2)
Drive JLMS DVD-ROM XJ-HD166
Firmware Version DD06
MID MKM A02
Capacity 4.38 GB
Random 108 ms
1/3 121 ms
Full 212 ms
Burst Rate 26243 KB/sec
I don't know why the cpu usage shows as n/a. Yesterday I got
in the same test case.
Tell me, please, what do you think about this. BIOS upgrade? New ATA/100 DVD reader? A second IDE controller card? Or just "leave it as it is"?...