SATA "channels", DVDRWs, and HDDs

[swaaye]

So, has anyone else noticed how SATA still has a master/slave contention going on with devices?

I've found that if I have a SATA DVDROM and a HDD on the same "horizontal row pair" of SATA connectors on my mobo (GA P35-DS3R), they show up as master/slave in Windows. Now if I burn a disk on that DVDROM, the HDD that's also on that "channel" is seriously bottlenecked even if the DVDROM isn't pulling data from it (it's pulling data from a different HDD).

A pair of DVDROMs don't like to be doing things together on the same channel, either.

I don't know if this happens with SATA HDDs on the same "channel" or whether it's an artifact of ATAPI.... I've also been wondering if AHCI solves it.

 

[Bludd]

ACPI? You mean AHCI, right?

My motherboard's (Asus Commando, Intel P965) manual marks some of the SATA headers as non-bootable. I have loaded all of them with HDDs and just made sure the drive with WinXP on was connected to one of the bootable headers. I use a PATA DVD-RW and since it's alone, I have no bottlenecking when using it.

Are you experiencing this only with SATA optical drives? What about the HDDs?

Anyway, when I switched to AHCI, my multithreaded drive accesses sped up and everything got more responsive.

 

[BRiT]

Nope. Never ran across this issue at all. I'm running an ABIT IP-35 Pro and using AHCI protocol. Each drive shows up as it's own channel and I have 5 of the 6 ports in use with 3 hard drives and 2 Optical Drives.

What mode do you have the SATA channels set to use within BIOS? Are you running with AHCI or IDE or RAID mode?

SATA Modes

 

[swaaye]

Yeah I meant AHCI.... My brain does some crosslinking on those two acronyms occasionally. Hell, I know I was consciously trying to prevent it that time too!

 

[swaaye]

Nope. Never ran across this issue at all. I'm running an ABIT IP-35 Pro and using AHCI protocol. Each drive shows up as it's own channel and I have 5 of the 6 ports in use with 3 hard drives and 2 Optical Drives.

What mode do you have the SATA channels set to use within BIOS? Are you running with AHCI or IDE or RAID mode?

SATA Modes

I'm in legacy mode. Haven't seen the added boot time that AHCI adds as worth it, really. I don't use eSATA and NCQ might as well not exist for my single-user usage.

So, my SATA ports show up as PATA IDE controllers in Windows. I haven't tested this "channel contention" issue with AHCI.

 

[swaaye]

Are you experiencing this only with SATA optical drives? What about the HDDs?

Anyway, when I switched to AHCI, my multithreaded drive accesses sped up and everything got more responsive.

Yeah I think it may be a problem caused by ATAPI. Optical drives don't use the IDE interface in the same way as HDDs (see ATAPI standard) and it definitely caused speed problems back with PATA if you had a DVDROM busy on the same channel as a HDD (or tried using 2 DVDROMs on the same channel at once).

I have run AHCI before, but don't right now because it adds some boot time that annoys me and I never noticed its benefits when I did use it. No eSATA use here and NCQ is kinda placebo...

 

[Bludd]

My boot time got shorter with AHCI enabled.

 

[Davros]

so you need to run in legacy mode? you should also have an enhanced mode


Dont forget you need to enable ahci before installing an o/s (there are ways round it, but its a bit of messing about)

 

[swaaye]

I'm betting that the "native" mode in my BIOS is the "enhanced" mode. It's separate from AHCI. As far as I can tell, it consolidates IRQs used by the IDE controllers.

 

[swaaye]

My boot time got shorter with AHCI enabled.

I spent several hours last night trying to get AHCI working on here. Wiped the OS and went at it. I have actually never bothered with it on this P35-DS3R mobo, just with my 780G board.

Well, I couldn't get the BIOS to be happy. I have 3 WD HDDs (640, 500, 1TB). The 640 and 1TB seem to be somewhat incompatible with this board's AHCI mode. It would freeze 9/10 times when detecting them. I couldn't even get it to go reliably with just the 640gig hooked up. I tried 3 different BIOS revisions. I cleared the CMOS settings a few times too. Nada. What a waste of time!! It booted successfully exactly one time. Strangely it was on the first try, which tricked me into wiping out my original XP install, unaware of the fun about to take place on the next reboot.

So I gave up and just put it back on legacy mode. Bummer. I was hoping to try out AHCI with this thing as it is loaded with 3 DVD-ROMs and 3 HDDs.

It certainly does not improve POST time though. There are actually two drive detect routines that it goes through. One sees the DVD-ROM on PATA and the JMicron chip that runs 2 of the SATA ports. The second routine is the Intel AHCI BIOS which detects the other 6 SATA ports. This is what freezes up on me. It's slower than the 780G for sure. It probably adds ~7 seconds to POST.

 

[Davros]

are all your sata drives sata 2 ?
and why do you need 3 dvd-roms
your board only has 1 ide channel which means you have a dvdrom on ide that may be messing with ahci

 

[Bludd]

Did you try updating the mobo bios?

I run my Asus Commando in AHCI enhanced. The POST time was slow initially, but I think my mobo/BIOS somehow caches the info so that the subsequent POST is faster. I just tested this by plugging in my USB 2 external HDD and the POST was slow again. I rebooted and it was back to being fast.

Also, when my system craches, the POST is slow again, but next reboot it is fine.

 

[swaaye]

Bludd,

Yea I went through 3 BIOS versions. It just refused to work. Very disappointing and frustrating. I tried to do some web searches about it but didn't find anything really. I even tried different cables.

What is strange is that it booted fine the first time, found all the drives, and I ran through the first part of XP install. The next reboot and every subsequent try would just not go. It just sat at the detection screen indefinitely, or gave a "failed to detect drive" error after a long wait.

There may be some sort of defect with the detection on this board that I never noticed before because I've never bothered with AHCI on here before.

 

[Bludd]

Bad luck, man. You'll live without it, though, since you've gone this far without it. Just hope your next board will support it flawlessly.

 

[swaaye]

I decided to give it a try again and it decided to work this time. No more lockups while detecting and I installed Vista. However, there still seems to be something wrong with AHCI (board or drives, who knows). I burned 5 coasters (both DVDRWs failed burning with weird LBA errors at ~82%). So, back to legacy mode again.

This is why I tell people to stick with legacy mode unless they really NEED it for eSATA. Fortunately going from AHCI -> Legacy IDE doesn't require reinstalling Vista.

 

[Bludd]

And you cannot decide to selectively enable AHCI either, so you could run the optical drives in legacy mode. I have heard bad things about optical SATA drives and that was the reason I went PATA last time around.

I guess the BIOSes and drives can only get better, though.

 

[BRiT]

Hopefully the other motherboard makers figure out what Abit has had figured out for a while on their P35 board. I have no issues at all with my 2 SATA Optical drives (One DVD Burner, One BluRay Burner) in AHCI mode. Maybe the quality drives helped or maybe I got lucky.

 

[swaaye]

Yeah I have a feeling it could very well be the optical drive's fault. I have a pair of SATA Samsung SH-S203B drives running latest firmware. They were "cheap" (well as cheap as almost all of them are these days) but make good quality burns and are quiet.

 

[BRiT]

From what I've seen, that model Samsung still provides one of the best media burn quality available anywhere.

This is a bit perplexing. I'm running the Samsung SH-S203N drive running firmware SB02. It was rather inexpensive. From what I read over at cdfreaks and other burner-knowledge websites, the two are very similar mechanisms providing very exceptional burn quality with one providing Lightscribe (N) capabilities.

The other is the LG GGW-H20L running firmware YL03.

 

[swaaye]

They do make great burns. They just don't seem to like AHCI on this P35-DS3R board. Or the board doesn't like them. On the "legacy IDE" mode they work flawlessly.

Now that I think more about it, I had one running AHCI on my GA-MA78GM-S2H 780G mobo and it worked fine.