nForce PCI writes mystery: Solved!

Last week, we revealed the possibility that NVIDIA’s nForce chipset may have a problem with PCI writes. We weren’t sure at the time what exactly was the cause, so we turned to you for results. We also checked with MSI and NVIDIA to get their input on the matter. Now we have some answers.

Your testing results provided a clear pattern. Regardless of processor, OS, adapter, or hard drive differences, the MSI K7N420 Pro would not write data any faster than 20MB/s. Meanwhile, the Asus A7N266 series posted numbers down in the 3MB/s range. However, A7N results also proved that the newest beta BIOS resolved these PCI writes problems. Abit and Leadtek results stayed elusive until the last minute, but you guys came through with scores in the 61MB/s and 58MB/s range, showing that these boards are unaffected by the PCI writes problem. With those results in hand, it was beginning to look more and more like a BIOS issue—that the culprit was more Darth MSI than Darth NVIDIA.

Then we received a call from Bryan Del Rizzo, the Integrated PR Manager at NVIDIA who oversees the nForce platform. He confirmed that a fix should be available in the form of a BIOS update. Once the BIOS update has been applied, the “MRM prefetch” option must be enabled. (Depending upon the whims of the motherboard manufacturers, this setting could be obfuscated from the user and set to “enable” by default.) NVIDIA referred us to the manufacturers to confirm who did and did not have a BIOS ready.

We know Asus has their BIOS ready here. We only had two Abit results, one score of 34,779MB/s and another at 61,512MB/s. One reader, using different test parameters, presented four sets of Leadtek results. He tested both Leadtek’s shipping and current BIOS, and I’m happy to say both revisions scored the same: 58MB/s.

All that leaves is MSI owners without a BIOS update and fix. Of the thirty-one sets of results you guys submitted, seventeen of them are from MSI users. Since the MSI nForce board saw the largest market penetration, MSI’s unresponsiveness is especially disappointing. MSI hasn’t responded to our questions about this problem, so we have no timetable for a BIOS fix from MSI.

So what was the problem with the nForce? NVIDIA didn’t give us exact details. My theory is that we are seeing a prefetch issue, much like the problem with the Intel 850 and 860 chipsets. If the nForce and 850 issues are similar, then the BIOS fix will only provide PCI write bandwidth up to a certain point. The 850 and 860 stopped right at 90MB/s on PCI writes. Once MSI has released a BIOS with the fix, it will be easier to determine whether or not that is the case. TR readers like Kraquen, with his RAID-0 X15 Cheetah setup, should be able to saturate the bus.

Of course, this last bit of speculation is just that. In reality, the problem could be far more benign. It could have been a typo in the data sheets provided to manufacturers or a human error in the design of the reference BIOS. We’ll probably never know for sure, and in the end, all most people want is the fix. A big thanks to the community as a whole for spreading the word and providing us the results we needed.

Comments closed
    • Anonymous
    • 18 years ago

    Hi there,

    My ASUS A7N266-VM motherboard with nForce chipsets is giving me problems. When I enable the MCP Dolby Digital in the BIOS, my Windows XP stalls???

    Can anybody help me??

    sacratus@softhome.net

    Thanx

    • Anonymous
    • 18 years ago

    I have a7n266-c.i used 3com 3c905(managment) on it
    it was too slow comparing to any other PC in network

    • Anonymous
    • 18 years ago

    oops…datasoul.net

    • Anonymous
    • 18 years ago

    I’m just waiting for the PCI fix in a release BIOS…. My 2960UW controller is experiencing MAJOR suckage right now….

    Lord Balance (www.daasoul.net) (server down until new drive darnit)

    • Anonymous
    • 18 years ago

    die thred die

    • Anonymous
    • 18 years ago

    Taking the forum down because of this is pathetic and they’re only asking for more bad publicity. Which they will get.

    • cass
    • 18 years ago

    MSI forum down till July? At least is says so on their site. Have any MSI people talked to Tech-Report yet?

    • Deth
    • 18 years ago

    Well I have just flashed my A7N266-E with the beta BIOS, and I’m praying it takes care of my problem. Burning CDs 🙁

    I have a venerable Plextor 12x4x32 SCSI and an even more ancient Adaptec 2940UW, and on this PC my write are terrible! I can’t do DAO (as I could in the past on a “lesser” machine), and even using TDK branded 32x media I am rarely able to burn higher than 8x without many coasters. On my primary machine which I “upgraded” from SCSI to IDE in the form of a Plextor 40x12x40, I can regularly burn at 32x on said media while doing various other tasks with never a problem (thanks partially to Burn Proof which the 12x lacks).

    • Anonymous
    • 18 years ago

    If anything, this fiasco should warn everyone to stay away from MSI products.. I’m still ticked off that there’s absolutely no support for the MSI-6309 I bought awhile back – it was actually selected for various awards and recommendations, yet has serious issues with WinXP, and the Win2000 situation is only marginally better. Why? How about: no friggin BIOS updates. Looks kind of like some kind of pattern to me..

    They did make some nice slockets, however, which thankfully don’t have any BIOSes to be (not) updated.

    • cass
    • 18 years ago

    well, I did not have any problems… read carefully.

    The only problem was with the asus board which has a dead sound card/riser plug.

    I did not blame any motherboard maker for not being able to switch the drive, I simply stated the Asus is know to be broken in the sound card/ sound card riser system causing an error loading the drivers for the System management bus and the sound card. That precluded me disabling the integrated sound in bios for my testing.

    And I moved the drive back and forth out of laziness just to see if it would work. And it works great. I was able to move XP from the LeadTek to the ASUS, and then to the MSI without any problems whatsoever. This works well because all three boards are the same chipset, and the only real difference being in the way they each handle the integrated sound. And loading the LeadTek first got the latest version of Nforce drivers loaded. Loading the MSI first with Win 2000 pro loaded the oldest drivers first, and could have been why the Asus would not fire off on the 1st try.

    If an OS was supposed to be plug and play that was a good test not?

    Windows 2000 PRO was not as graceful as Win XP, but that is not unexpected since Win XP is newer and should have better suppport for new hardware.

    At first I loaded the 40 GB system HDD with win xp home, and I could read the Raid Data created under Win xp PRO and play my multimedia files on the raid, but Atto could not create Its test file there. gave me a could not open file error. So I loaded XP Pro up and continued with no problem.

    I also left the raid drives in another case, plugged the drives in to another independent power supply and simply moved the raid card to which ever system was under test. I never lost the raid array, or had it fail to read/write with win XP or 2k.

    I was also able to jerk a 10GB hdd out of my epox mvp3 ep51 (I think this is right description) running win 95 on a AMD K6 3d platform and plug it straight to the Asus A7n 266E and get it to boot. I was able to dial the internet and surf using netscape and IE. Of course, there are no win 95 drivers for the Nforce, so the video and Ram drivers and (some bus I forget the exact description) I never got to work right. I used 98se drivers to get everything else working.

    I Have also took the 40 GB system drive from an MSI K7n420d pro system and simply plugged it in to an MSI Kt266a Pro2 system and booted it up with no problems… other than inserting the driver disk when asked.

    I was capable (or lucky) enough to discover right off the bat with my Nforce boards MSI and Asus had big problems with Pci writes though. I was no where near the first to discover that either. And for my persistence I was and am being rewarded by being flamed and told not to start being a PC Tech. I care less, I do not get paid to help others or test, I moved on to another chipset mother board and waited till enough Nforce boards got out to get the problem noticed more.

    I won’t comment on my sanity. I do not work everyday as a computer technician (Ryu sniffed that one out fairly early). I was not trying to get perfectly optimized installs, just trying to get lots of results in a short period of time. My numbers look fine when compared with the rest, so I don’t feel I whiffed too bad.

    And I don’t think It was bad techness as how I documented my method and it is therefore reproducible. I don’t hide behind an anonymous label to post opinions/results either.

    Good Night.

    • Anonymous
    • 18 years ago

    Cass:
    May I ask why you thought it a sane move to move a windows install back and forth between different rigs? That just sounds downright silly to me. Every manufacturer engineers there products differently. Regardless of the hardware present on the motherboard, this is just asking for trouble. I’m not surprised you ran into issues. I hardly think it’s fair blaming the mainboards for your crakpot move of transferring a single operating system to multiple machines. That only works in scenarios where the hardware is identical (i.e. same make, model, and manufacturer.) That’s bad techness man, pure bad mojo.

    • cass
    • 18 years ago

    AG# 25 The issue affects pci bus writes. If you are hooked to the onboard, 30MB/s is about right.

    Tech Report guys, Are yall hearing anything? (from MSI) or have they just shut down and went to damage control.

    • Anonymous
    • 18 years ago

    I have a xp 1800 512 ram a 7200 rpm hardrive and the k7n420 pro, I get about 30 mb write…what kinda number should I execpt?

    • Anonymous
    • 18 years ago

    > All that leaves is MSI owners without a BIOS update and fix.
    > MSI’s unresponsiveness is especially disappointing.

    Well, doesn’t sound like a real discovery… The MSI forum is full of complaints, but they don’t seem to at least have a look at them. I was the unhappy owner of a MSI 845 ARU, and since they didn’t fix any of the problems reported in the forum, nor did they answer my emails, I left the bad MSI side and switched to an Asus board : more expensive, but tech support is something you can’t live without when you need BIOS updates.

    May the MSI customers be heard, but they should cross their fingers very tight…

    • Anonymous
    • 18 years ago

    And the MSI forum continues to be ‘un-availaible’.

    • Anonymous
    • 18 years ago

    I like bags of fish heads. Whole fish – thats disgusting…

    • Anonymous
    • 18 years ago

    I like fish.

    • Anonymous
    • 18 years ago

    You people are gay and I hope you eat a bag of fish.

    • bdwilcox
    • 18 years ago

    To AG#15,

    Yes that is the same Bryan Del Rizzo that left the sinking MaxPC ship when they gave the boot to boot. Bastards.

    • Anonymous
    • 18 years ago

    *[

    • cass
    • 18 years ago

    Wow, Thanks Ryu.

    What do I do different next time to keep you from flaming me for four months? 🙂

    Good Work.

    As far as I can tell on the stability question of anonymous #9, That is very hard for me to differentiate among the 3 Nforce boards I have.

    The Leadtek is what I am getting to replace my office computer with, and that is based on it being cheap, and more than adequate. I won’t be doing anything more than some simple 3d cad/cam, video editing and web surfing.

    I like the support of ASUS better so far, they have fixed the pci bus to workable values, and at least I could get them on the phone. They called be back with a problem I have, and did not hesitate with an RMA. The RMA I have is for a sound card riser dying.

    I did not have any trouble loading Win xp or Win 2000 on any of these boards except for W2k and the ASUS.. see next paragraph. I was able to load XP professional on one HDD using the leadtek and transfer the same drive to the ASUS and MSI without reloading all the drivers or a bluescreen. The thing would just boot up, find all its new hardware install drivers and prompt me for the disk if there was a driver not found.

    I loaded Win 2000 on the MSI, and tried to switch drive to ASUS but got BSOD.. Clean Install did not work either. I suspect the dead Riser was giving win2k grief, so I gave up on running W2k on it. I have a problem with system management bus in the device manager of Winxp, but it runs. W2k loaded great on the Leadtek.

    • Anonymous
    • 18 years ago

    I had the exact write problem with my MSI nForce 420D. My setup included a Promise Fastrak TX2 RAID, 2 IBM 120GXP 60GB and while the read speed was fantastic according to several different benchmark applications, the write speed was terrible, hitting the ceiling right at 20MB/s as mentioned in this thread. I had to swallow the cost of that board (it’s a custom-built for a customer) and replaced it with the Abit NV7-133 RAID using those 2 hard drives with it’s onboard RAID controller. The read and write scores were pretty much inline with what it’s supposed to be. I now will have to hold on to that MSI board for a while til they have the updated BIOS that fixes the problem.

    • Anonymous
    • 18 years ago

    Bryan Del Rizzo? Isn’t that the former Max PC guy?

    • Steel
    • 18 years ago

    It’s cool you guys got this thing figured out. Sorry I couldn’t provide any results, I would have had to rip apart 3 computers to do it and there seemed to be plenty of input anyway. As the only thing on the PCI bus is a 10/100 ethernet card I think I’ll wait for the Asus BIOS to come out of beta before trying it out.

    • kraquen
    • 18 years ago

    woohoo, i made it onto the front page! =)

    • Ryu Connor
    • 18 years ago

    [q]Ryu, I would like to extend a big “thank you” to you for your time and the use of TR to help to get some results that are useful to the whole community.[/q]

    Your welcome, though I didn’t do it alone. The whole TR staff deserves credit.

    [q]2. IDE onboard ist limited to 92mpbs[/q]

    That’s called ATA100. Seeing as you had a winking smiley I’m not entirely sure if you were joking or not.

    • TheCollective
    • 18 years ago

    AG #9:

    I would say with MSI’s problems right now the Abit NV7-133R looks pretty cool. Everyone seems to be impressed with it.

    • Anonymous
    • 18 years ago

    And they’d have gotten away with it, too. If not for those pesky kids and that darned dog!

    • Anonymous
    • 18 years ago

    Great work guys. Solving probs like these is what the community is all about, I reckon. It saves me from releasing my Darth Nvidia material too.

    While we’re on the topic, which nforce mainboard would you guys consider the best/most stable of the lot? Seriously looking at upgrading this VIA thing.

    • Yoweigh
    • 18 years ago

    AG #7

    [q]1. I

    • Anonymous
    • 18 years ago

    The Problem is solved?

    1. I

    • TheCollective
    • 18 years ago

    [quote]This problem does not rear its ugly head if you use the onboard IDE controller, correct? As long as you are not using an add on card there is no problem? The average user with just a HD, CD-Rom and burner would never be effected.[/quote]

    Correct. The onboard controller uses the HyperTransport link and therefore has nothing to do with the PCI bus. Onboard controllers are unaffected.

    • IntelMole
    • 18 years ago

    Hurrah for Tech Report!

    Thanks to all those who participated, even though I didn’t know about the issue or know anyone who had a nForce board, this sort of thing is really a good idea…

    Keep up the good work, and we may just get rid of all the PCI issues before it’s kicked to the ground in favour of PCI-X 🙂

    Erm, no :-),
    IntelMole

    • Anonymous
    • 18 years ago

    This problem does not rear its ugly head if you use the onboard IDE controller, correct? As long as you are not using an add on card there is no problem? The average user with just a HD, CD-Rom and burner would never be effected.

    • Anonymous
    • 18 years ago

    Well well, what do you know?

    The MSI forums are unavailable at the moment… under maintenance claims MSI…

    Greg Stanford

    • Xylker
    • 18 years ago

    Ryu, I would like to extend a big “thank you” to you for your time and the use of TR to help to get some results that are useful to the whole community.

    Thank you!

    • TheCollective
    • 18 years ago

    Glad to help, Ryu. I feel better now knowing that my recomendations of nForce based motherboards weren’t misinformed.

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