Intel G2 SSD running in PIO mode - SOLVED

wgoldfarb

Senior member
Aug 26, 2006
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I just noticed that my new Intel 80GB G2 SSD is running in PIO mode 4, and I cannot enable DMA mode. I go into device manager, click the "Enable DMA mode" checkbox, click "Ok", and receive no errors. But when I check again, PIO mode is still there and the DMA checkbox is unchecked.

My other 2 drives (a spindle HDD and an optical drive) are all running in DMA mode 2. All 3 drives are connected to SATA ports on the ICH8R southbridge of my Asus P5B. The ICH8R is configured in the BIOS to run in Enhanced AHCI mode. This is a brand new installation of Windows 7 x64 in a brand new Intel SSD. Firmware on the SSD is 02HD.

Any ideas as to why the SSD is running in PIO mode, or why I cannot enable DMA mode?

TIA!

EDIT: I solved it: pls see my post below.
 
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wgoldfarb

Senior member
Aug 26, 2006
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More info: I used AS SSD to check transfer rates, and my transfer rates seem in line with what others are reporting here: 250 MB/s Seq reads, 85 MB/s seq writes, 21 MB/s 4K random reads, 44 MB/s 4k random writes.

IIRC PIO mode 4 is limited to transfer rates of around 16 MB/s. So clearly something is very strange here. If Device manager is correct, and my SSD is in PIO mode 4, I should not be getting such high transfer rates.

Any ideas?
 

amdhunter

Lifer
May 19, 2003
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I had this bug on my Vista computer when I first connected my OCZ Vertex. I ended up removing the controllers under IDE/ATA ATAPI controllers in device manager and re-detecting them.

Havent had an issue since.
 

wgoldfarb

Senior member
Aug 26, 2006
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Ok, I solved it -- not sure why this would have worked, though. I simply changed the port that my drives are connected to on the MoBo. Using Asus numbering (1 to 6), the SSD went from Port 1 to Port 5, spindle HDD from port 2 to Port 6, and Optical drive from Port 3 to port 4. SSD now shows UDMA mode 6 instead of PIO. Interestingly, HDD went from UDMA mode 2 to UDMA mode 6. Optical drive remains in UDMA mode 2. I did not change anything else, I simply unplugged the SATA cables from one port and moved them to the new port.

Even more strange is that xfer rates for the SSD are unchanged. I'm not exactly sure what is going on, perhaps it has to do with Asus implementation of the SATA modes, or some strange driver issue. It sounds as if ports 1 and 2 are "slow" ports?

If anyone here has an ASUS board with an Intel ICH8R southbridge (or perhaps any Intel southbridge?), and you have an SSD or HDD connected in ports 1 or 2 of the ICH8R (i.e. not the JMicron controller) in your MoBo (ports 0 and 1 in device manager), you may want to check what mode Windows 7 says your drive is working in. It did not seem to affect actual xfer rates, but you never know.
 

qazwsxokmijn

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Dec 7, 2009
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Ah, that's interesting. What are these different UDMA modes anyway? Do all SATA devices (optical drives, HDD, SDD) all need to be under a specific UDMA mode?
 

wgoldfarb

Senior member
Aug 26, 2006
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qazwsxokmijn: PIO and UDMA are different transfer modes: how the drive communicates with the rest of the system. In essence, they determine how fast data can travel to and from the drive. PIO modes are very old modes with limited transfer rates. UDMA modes are newer, with higher transfer rates. You can see what the different UDMA modes are here:

http://www.pcguide.com/ref/hdd/if/ide/modesUDMA-c.html

In general, the higher UDMA mode, the newer it is and therefore the faster it is.
 

deanx0r

Senior member
Oct 1, 2002
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SATA port 1-6 (the red ones) are from the ICH8R. You need to switch them to AHCI mode in the bios, and install their drivers if you are using Windows XP. The other SATA ports (black) use the JMICRON controller, and also need to be switched to AHCI mode if you want all the benefits of using SATA ports (hot swappable pnp).

My guess is that you are probably running those ports in IDE mode. Look into the BIOS.

EDIT: NEVERMIND, didnt entirely read the first post.
Windows probably doesn't have the proper driver, because under AHCI mode, it shouldn't even list the drive as IDE devices with UDMA or PIO modes.
 
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qazwsxokmijn

Member
Dec 7, 2009
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qazwsxokmijn: PIO and UDMA are different transfer modes: how the drive communicates with the rest of the system. In essence, they determine how fast data can travel to and from the drive. PIO modes are very old modes with limited transfer rates. UDMA modes are newer, with higher transfer rates. You can see what the different UDMA modes are here:

http://www.pcguide.com/ref/hdd/if/ide/modesUDMA-c.html

In general, the higher UDMA mode, the newer it is and therefore the faster it is.
Cheers mate. Where's the thumbs up emoticon.....
 

wgoldfarb

Senior member
Aug 26, 2006
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Windows probably doesn't have the proper driver, because under AHCI mode, it shouldn't even list the drive as IDE devices with UDMA or PIO modes.

deanxOr: what should the mode be listed as if the driver was correct?

In device manager, under IDE ATA/ATAPI devices I see the 6 ATA channels plus the "Standard AHCI 1.0 Serial ATA controller". Each ATA channel shows 2 driver files: atapi.sys and ataport.sys. In addition, the AHCI controller shows the same 2 files, plus msahci.sys and pciidex.sys. I'm running Win 7 x64, in case it makes any difference.

CrystalDiskInfo shows the drive supports NCQ and TRIM. Based on this, and on the transfer rates I am getting, it seems the drive is operating correctly in AHCI mode. The problem appears to be how device manager sees the drive, not with how the drive is really operating. Anyway, since the drive seems to be operating correctly, I won't worry too much about it.
 

SolMiester

Diamond Member
Dec 19, 2004
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Can someone please advise where I can get AS SSD, i have just flashed my A-Data SSD to 1848 for TRIM and wish to check!
 

Nomgle

Junior Member
Sep 6, 2006
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I just noticed that my new Intel 80GB G2 SSD is running in PIO mode 4, and I cannot enable DMA mode. I go into device manager, click the "Enable DMA mode" checkbox, click "Ok", and receive no errors. But when I check again, PIO mode is still there and the DMA checkbox is unchecked.
I have exactly the same issue on my Gigabyte GA-P35C-DS3R (rev. 2.0) (Intel P35 + ICH9R Chipset).

My Intel drive is running PIO4 just like yours, and one of my Hard Drives is stuck in UDMA Mode 2 - the rest are UDMA Mode 6 as they should be.

Your solution is interesting - I'm also going to try moving my connections around.

What's really strange though, is that running in PIO4 mode isn't affecting performance at all - if you try this with a mechanical drive, then it absolutely DECIMATES the performance - Windows can't even play an audio file at the same time as accessing the drive. I suspect it's the reporting at fault, and we're really running UDMA 6 behind the scenes.
 

wgoldfarb

Senior member
Aug 26, 2006
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I suspect it's the reporting at fault, and we're really running UDMA 6 behind the scenes.

I believe you are right. There is no way the drive was really operating in PIO mode, or even in UDMA 2, for that matter. The transfer rates I was getting are impossible in those modes. So, I think the drive was operating correctly in UDMA 6, but being reported incorrectly by the Windows device manager. Maybe an issue between the driver and device manager. Who knows. In any event, it is good to know that it seems to be "just" a reporting error, and does not affect actual performance.

Since you have a different Mobo, Chipset, Southbridge, and even MoBo manufacturer than I do, and the problem exists with different types and brands of drives, I think it is "almost" safe to say that hardware is not the problem. Perhaps the problem is with the AHCI driver itself?
 

Nomgle

Junior Member
Sep 6, 2006
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Since you have a different Mobo, Chipset, Southbridge, and even MoBo manufacturer than I do, and the problem exists with different types and brands of drives, I think it is "almost" safe to say that hardware is not the problem. Perhaps the problem is with the AHCI driver itself?
There's another guy here - http://forums.anandtech.com/showthread.php?t=2031868 - with exactly the same problem ! He's seeing it on his mechanical Western Digital drives.
 

Strife21

Junior Member
Dec 20, 2005
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FYI, I have a completely different motherboard and drive and have the same issue.

I just wanted to say I am having the same exact issue and have the WD WD AAJS as well. I am using a EVGA P55 SLI motherboard. If I plug into SATA Port 0 on the motherboard and use ACHI I get Multi-Word DMA Mode 2 listed in Device Manager. If I then switch it to SATA Port 2 I get Ultra DMA Mode 6.

If I switch from ACHI to IDE both ports show as Ultra DMA Mode 5.

I end up with the same hard drive score for the windows performance index (5.9) and similar scores in HD Tach, ATTO and HD Tune in one mode vs. the other. Although I did notice a slight increase in maximum read speed when not on port 0.
 

jkroeder

Member
Dec 7, 2009
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Sorry for bumping an old thread but it appears I have this issue too with a brand new Intel X25-M 80GB and a Gigabyte P35-DS3L v2 board.

I have 3 SATA drives on a board with only 4 SATA connectors total. So I can't shift the drives to different ports the way wgoldfarb was able to. If I move the X25-M to port 2 from port 0 and leave my other drives unconnected, Win7 Pro sets it to UDMA6.

Plug it back in to port 0 and it goes back to PIO Mode 4. As far as performance goes, it seems to be normal so it's not a big deal but hoping it's not an issue down the road.
 

Nomgle

Junior Member
Sep 6, 2006
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I never did get to the bottom of it - it appears to be a fault with the Intel Storage Controller, which may or may not be fixeable with a BIOS update (if your board manufacturer can be bothered :) )