nForce PCI writes issue @ Tech Report

[Aboroth]

Wow, another issue.

I have a friend with the K7N420 and no matter what 3d card, power supply, or any combination of good hardware or OS he uses the computer resets after about five minutes of 3d games, using the onboard video or a Geforce 3, and only when he playes 3d games, and nothing is overclocked. He posted a comment on an MSI forum about it and it looks like a significant number of people have that exact same problem. I am guessing a run or two of those were screwed up in that way.

Looks like the K7N420 just sucks.

 

[Gstanfor]

Not quite right, the Hypertransport link is between the north and south bridges. The PCI bus is still a 133MB/s bus running to the south bridge.

That is what I said. The PCI bus does not exist as such until you hit the southbridge unlike conventional chipsets where the PCI bus is the link between the north & south bridges. The result is it is almost impossible to clog the PCI bus up due to to things like USB, AGP, sound etc on the nforce, since these all have their own share of the 800mb/s hypertransport link.

One thing I can think of is maybe the logic that takes the PCI datastream and converts it to a packetised h/t stream could be improved under certain conditions, but, this doesn't explain why other heavy PCI users don't suffer the same way as disk controllers on the PCI bus - if it affects one type of card it should affect them all.

You also have to take into account the fact that it seems that write operations are being affected, not reads which indicates to me that the problem doesn't lie in the southbridge or PCI bus (since the CPU or DMA memory transfer would initiate the write and the data would have to travel through the northbridge and h/t link first, whereas reads are fast and and the southbridge is more in control of that since the data originates from the southbridge and travels back up the chain to the cpu/memory). That's why I think it will turn out to be drivers/BIOS issue myself.

I hope all that made some kind of sense.

Greg

 

[bluemax]

Originally posted by: Sunner
Seems like it's damn hard to get the PCI stuff right.
Heck everyone seems to have problems with it, Intel, VIA, now nVidia.

Intel had PCI "issues"?? I must've missed that one! :Q How's SiS doing?

 

[NFS4]

Originally posted by: jaeger66

Originally posted by: NFS4
Actually, I ordered the NV7-133R and a Western Digital 800JB last night from NewEgg

Should have stuck with the MSI, it's the only true nForce board out there.

HUH????

How do you figure?? The Abit is the most feature-filled nForce board on the market.

 

[oldfart]

My 1200JB really screams on my i845 setup!

 

[Gstanfor]

There is no problem with IDE speed on nforce (when you use the built in iDE controller) either. That is extremely quick. The drive performance problem only happens with PCI drive controllers and then only with writes.

Greg

 

[jaeger66]

Originally posted by: NFS4

Originally posted by: jaeger66

Originally posted by: NFS4
Actually, I ordered the NV7-133R and a Western Digital 800JB last night from NewEgg

Should have stuck with the MSI, it's the only true nForce board out there.

HUH????

How do you figure?? The Abit is the most feature-filled nForce board on the market.

The Abit and Asus boards both use Realtek Ethernet. I guess they had a surplus of 81xx controllers they had to unload. The Abit also uses a Realtek ALC650 audio codec, and I'm not quite sure why. I'd have thought the APU could handle everything, maybe I'm wrong. I don't think MSI or Asus use it but I'm not sure.

 

[jaeger66]

Originally posted by: Gstanfor<brThat is what I said.

Actually, you said "PCI data is sent to and from the southbridge on an 800mb/s hypertransport link". But the implication is correct.

 

[Adul]

nVIDIA MCP-D built in Audio Processing Unit w/ 256 total voices
Supports AC3 encoding
Realtek ALC650 (AC-Link)
Supports 6CH DAC for AC3 5.1 CH output
Professional digital audio interface supporting 24-bit SPDIF OUT

not sure what you are talking about jaeger66. realtek doesnt do the audio, but the ac link.whatever that is.

 

[NFS4]

Originally posted by: jaeger66

Originally posted by: NFS4

Originally posted by: jaeger66

Originally posted by: NFS4
Actually, I ordered the NV7-133R and a Western Digital 800JB last night from NewEgg

Should have stuck with the MSI, it's the only true nForce board out there.

HUH????

How do you figure?? The Abit is the most feature-filled nForce board on the market.

The Abit and Asus boards both use Realtek Ethernet. I guess they had a surplus of 81xx controllers they had to unload. The Abit also uses a Realtek ALC650 audio codec, and I'm not quite sure why. I'd have thought the APU could handle everything, maybe I'm wrong. I don't think MSI or Asus use it but I'm not sure.

I think you are confused. As Adul stated, Realtek does the AC link, NOT the audio. Every review even says so!! The LAN is also from the nForce controller. I don't know where you got your information, but whoever it was needs to be shot

 

[jaeger66]

Originally posted by: NFS4
I think you are confused. As Adul stated, Realtek does the AC link, NOT the audio. Every review even says so!! The LAN is also from the nForce controller. I don't know where you got your information, but whoever it was needs to be shot

It's in the manual, which I downloaded. Page 1-2. "Realtek 8201L physical layer" They are using the nVidia MAC with the Realtek PHY. The ALC650 is an audio codec generally used with the VIA 8233 south bridge host controller. I just don't know why it's on the Abit board.



ALC650

Realtek 8201L

 

[kgraeme]

Originally posted by: jaeger66

Originally posted by: NFS4
I think you are confused. As Adul stated, Realtek does the AC link, NOT the audio. Every review even says so!! The LAN is also from the nForce controller. I don't know where you got your information, but whoever it was needs to be shot

It's in the manual...

 

[Adul]

NFS4, it uses a realtek controller for the network card.

 

[NFS4]

So does the NV7-133R use nForce audio or what????? The LAN really doesn't matter. A NIC is a NIC is a NIC to me.

 

[kgraeme]

Originally posted by: NFS4
The LAN really doesn't matter. A NIC is a NIC is a NIC to me.

Unless one has significant CPU overhead and one doesn't.

 

[NFS4]

Originally posted by: kgraeme

Originally posted by: NFS4
The LAN really doesn't matter. A NIC is a NIC is a NIC to me.

Unless one has significant CPU overhead and one doesn't.

At work, I've used hundred of NICs from ISA to PCI. To tell you the truth, when transferring files, or surfing, or connecting to our network, I haven't noticed not one bit of difference between them in the "real world."

With a 1.5GHz Athlon XP, I'm not exactly bitchin' about CPU cycles anyway

 

[RyuConnor]

Abit NV7-133R:Windows XP using APIC

http://naples-air-center.com/APIC-IRQ.jpg

MSI K7N420 Pro:Windows 2000 SP2 using APIC

http://www.geocities.com/ryu_connor/irq.htm

The Abit, Leadtek, and MSI boards are all full implementations of the nForce.

The MSI uses ADI1885 AC97 codecs as interface/output points for the APU's host decoder.
The Abit uses ALC620 AC97 codes as interface/output points for the APU's host decoder.
The Leadtek uses ALC620 AC97 codes as interface/output points for the APU's host decoder (I believe).

This normal. If you go out and buy a Turtle Beach Santa Cruz, Hercules Game Theatre XP, or even a Creative Live! or Audigy card you will get a DSP + AC97 codecs.

The presence of a different companies codecs on the nForce does not mean it lacks the APU audio capability. There is one exception to that, the C-Media 8738 chip. That is the chip used on the A7N266 and the current Chaintech nForce2 board. The C-Media is a single chip DSP + Codec design, if you see one of these then the APU has been passed over. The A7N266-C, A7N266-E, and A7N266-VM all use the APU instead of C-Media audio.

The situation for the NIC is similar. Abit is using a Realtek PHY interface. MSI uses a company called ICS. I don't know about Leadtek. These are just like the AC97 codecs, they don't influence what driver you use, they are simply a needed layer. Only the Asus series of nForce boards do not use the nForce NIC. A Realtek 8139 is used in it's place.

 

[NFS4]

Originally posted by: RyuConnor
Abit NV7-133R:Windows XP using APIC

http://naples-air-center.com/APIC-IRQ.jpg

MSI K7N420 Pro:Windows 2000 SP2 using APIC

http://www.geocities.com/ryu_connor/irq.htm

The Abit, Leadtek, and MSI boards are all full implementations of the nForce.

The MSI uses ADI1885 AC97 codecs as interface/output points for the APU's host decoder.
The Abit uses ALC620 AC97 codes as interface/output points for the APU's host decoder.
The Leadtek uses ALC620 AC97 codes as interface/output points for the APU's host decoder (I believe).

This normal. If you go out and buy a Turtle Beach Santa Cruz, Hercules Game Theatre XP, or even a Creative Live! or Audigy card you will get a DSP + AC97 codecs.

The presence of a different companies codecs on the nForce does not mean it lacks the APU audio capability. There is one exception to that, the C-Media 8738 chip. That is the chip used on the A7N266 and the current Chaintech nForce2 board. The C-Media is a single chip DSP + Codec design, if you see one of these then the APU has been passed over. The A7N266-C, A7N266-E, and A7N266-VM all use the APU instead of C-Media audio.

The situation for the NIC is similar. Abit is using a Realtek PHY interface. MSI uses a company called ICS. I don't know about Leadtek. These are just like the AC97 codecs, they don't influence what driver you use, they are simply a needed layer. Only the Asus series of nForce boards do not use the nForce NIC. A Realtek 8139 is used in it's place.

Thanks for the THOROUGH explanation (although your second link is a image of an IRC chat).

I told ya'll that the Abit board was using all of the nForce goodies RyuConnor, don't be a stranger...POST MORE OFTEN, we need knowledgeable folks like you around here.

 

[RyuConnor]

Thanks for the THOROUGH explanation (although your second link is a image of an IRC chat).

Welcome.

The second image, the one with the IRC chat. Scroll to the window to the right. There you'll find a Windows 2000 device manager.

 

[kgraeme]

Thanks RyuConnor.

 

[NFS4]

Originally posted by: RyuConnor

Thanks for the THOROUGH explanation (although your second link is a image of an IRC chat).

Welcome.

The second image, the one with the IRC chat. Scroll to the window to the right. There you'll find a Windows 2000 device manager.

Oops...damn this crappy 800x600 rez I'm using right now at work

Welcome aboard!!

 

[Sunner]

Intel had PCI "issues"?? I must've missed that one! How's SiS doing?

Well not "issues" in the same sense as VIA's problems, but rather performance problems.
The i850 has a problem that limits it's PCI bandwidth to 80-90 MB/Sec.

Anyways, I'll see if I can dig it up, it was mentioned fairly recently.

 

[RyuConnor]

i850 Specification sheet:
http://developer.intel.com/design/chipsets/specupdt/298247.htm?iid=ipp_850chpst+prod_spec_82850&

The i850 and i860 suffered the same bug. The PCI bus within the ICH2 and only the ICH2 (The 64bit PCI controller on the i860 is exempt from this error) is limited to 90MB/s PCI writes.

PCI reads will go all the way to the real world limit of the PCI bus. Writes stop cold at 90MB/s. The issue was not a problem with the PCI bus itself, but instead with a prefetch device in the MCH (Northbridge). It would take too long to feed data to the ICH2 (Southbridge) and eventually the PCI bus would just terminate the request and move on with it's life.

There is a SCSI article at DaLanTech that actually shows this bug in action. Consequently it also showed that overclocking the ICH2/PCI bus opened up more headroom for PCI writes.

I'll post the link for that SCSI article later. At the moment I am typing this message through a remote session and it's very difficult thing to do.

http://www.dalantech.com/scsi-raid.shtml

 

[jaeger66]

I understand the difference between the interface and the controller, I guess what confused me was the fact that Abit pointed these things out where nobody else did(and not knowing the part numbers offhand.) .

 

[jaeger66]

Originally posted by: RyuConnor


The situation for the NIC is similar. Abit is using a Realtek PHY interface. MSI uses a company called ICS. I don't know about Leadtek. These are just like the AC97 codecs, they don't influence what driver you use, they are simply a needed layer. Only the Asus series of nForce boards do not use the nForce NIC. A Realtek 8139 is used in it's place.

OK...so why does the ALC650 have it's own drivers? For example, the MSI KT3 Ultra just uses the VIA 8233 audio drivers but the Ultra ARU uses the ALC drivers from Realtek. IOW, the generic drivers straight from Realtek can correctly ID whatever host it's connected to...is this just something they add with each revision(new hosts)?