PATA slowing down the SATA

I have my Drobo v2 connected USB to my desktop. Desktop is Vista installed on a PATA HDD. I also have an external FW400 HDD. I am copying over 900 GB from Drobo to ext. FW400 drive. Speed checks about 21MB/sec. After I copy the 900GB from the Drobo to the FW drive, I wanted to make one more copy on spare SATA 1TB HDD I had. So, after putting the 1TB drive in, I start the copy procedure fro the Drobo over USB to my SATA internal 1TB HDD. Speed is only 3MB/sec. I expected much faster. Does this make sense?

That could make sense depending on how everything is connected on your motherboard. For example, if SATA and USB share bandwidth somewhere down the line.

It might simply be that the USB->FW transfer wasn’t completely finished too. Did it speed up over time, or was it only 3 MB/sec for the entire USB->SATA transfer?

It’s 3MB/sec for the entire transfer.
I had tested writing to the Drobo from the internal PATA disk, and writing to the internal PATA from the Drobo. It would only ever show max 3MB/sec. I understood that making sense because of the PATA drive limitation.
I can clone my PATA disk over to the SATA, remove the PATA drive, and then try the read and write again to find out. I was wondering if anyone else had any insight.

PATA is capable of MUCH faster than a measly 3 MB/sec… Even really old ATA-33 drives can sustain better than that.

I would guess one of the following:
a. the PATA driver isn’t using bus mastering (didn’t install the manufacturer-supplied the chipset driver)
b. the cable is glitchy
c. the PATA drive itself is going bad
d. there is another device on the same IDE channel slowing things down

Definitely something in the PATA chain is a bottleneck.

a- I don’t really know, but will look into it
b- that is a could be. I have others that I could swap with
c- that is possible, but why would it affect my data transfers from the Drobo/USB to my 2nd internal HDD with is connected to the MOBO by SATA cable?
d- there is an optical drive connected by a separate ribbon cable to the motherboard, but the drive is not being used by anything.

I will check it out. I am planning to move the OS to a SATA HDD, but since I had this PATA HDD lying around(it’s a 250GB), I figured I would get some use out of it.

I appreciate your advice.

On c - normally they’d be unrelated, but I’ve seen bad/going-bad PATA drives repeatedly stall the system to varying degrees, even if Windows isn’t actively accessing it - mainly I think because Windows still polls it for info. If the mouse is “skipping” or otherwise not normally responsive, that’s a good indicator of a bad or going-bad PATA drive. Haven’t seen what the behavior is for SATA drives that are bad or going-bad yet.

On c- that is my assumption, too. I brought it up here as to ask, because you all are very helpful and experienced.
I will bring an update later. thanks.

My problem was settings in Device Manager and the BIOS.
I followed advice located here:http://www.devhardware.com/forums/showpost.php?p=916627&postcount=20

Somehow the IDE bus was in PIO vice DMA or max DMA mode. I am now seeing read/write speeds much much better.

Yup, PIO mode sucks performance-wise because it requires CPU attention.

My 900 GB took 4 days the first time. Last night I performed a fresh backup to my internal HDD. This time, it was complete in 7 hours. Such a relief.

bhiga, thanks for the responses. They should change your title. It’s refreshing to have someone give rational responses or advice to questions here (as opposed to other boards).

Wow 4 days vs 7 hours! Almost 14 times faster!! Funny how the little things can make such huge changes - it’s a good thing to remember for life in general. :slight_smile:

You’re welcome. While I’m not a moderator here, moderating (other) forums has been part of my job in the past, and it has become a bit of a hobby.

I get a lot of value from people’s responses here (esp from Spiney, Switcher, Docchris, others) so I try to give back more than I give grief. :wink: Hey, maybe I’ll put that in my sig.