Nforce 2 PCI bandwidth sucks

[Marshmallowman]

I have been quite happy with my a7n8x rev2 deluxe, but one issue that has me a bit peeved is the PCI bandwidth or lack of it.

Using saa7134 capture card , or twinham HD dvb-t card I can capture quite happily to the integrated ata100 channels. This is my main OS drive and I also have a swap space on it as well.(still no dropped frams)

However if I try to capture to the oboard SATA 3112 controller with seagate 160GB 7200 rpm drive attached I get horrible fram loss and corruption. (this is a standalone drive with no swap..etc or shared interrupts)

Now comparing raw disk write speeds the sata drive is a LOT faster than 80gb ata100 drive.

The si3112 controller is built onto the board but is implemented using the PCI bus.

so capture to 3112 and a pci capture card at 720x576 pal strains PCI beyond usabilty

Possible solution:

1. maybe the 3112 is a pci hog so I should replace it with a promise SATA controller? (could be waste of money if the PCI is the problem)

2. stick with the onboard ATA channels, eg get another ata drive and use that on the second channel(and perhaps find a cheap ide card to plug my DVD burner into)

3. Get a firewire box/hdd and capture to that so it avoids using PCI bus(any firewire boxs accept SATA drives?)

4. With the DVB-t card , it should be getting mpeg2 stream, which it decompresses and displays, but maybe I can get it to stream straight to hdd without decoding (saves a bit of pci bandwidth)

5.Find a magical PCI tweak for a7n8x /si3112 combo.

2 is probably my best and cheapest option. Any suggestions
It is very irritating, as I bought the 160G drive and the a7n8x with its 3112 sata controller specifically for capture but after a year of tweaking I have finaly come to the conclusion it is just not up for the job

[schmosef]

I've got the same board in one of my dev machines.

I found http://www.nforcershq.com to be a helpful site when I was having trouble with it a while ago.

IIRC, they have some sort of SATA "uber' bios for the board. I didn't try it though.

[Dr Mordrid]

A good indicator of a chipsets PCI bandwidth is if it can handle the RT.X100 since it needs gobs to do realtime previews and exports.

nForce is disqalified for use with the RT.X100. Same goes for VIA chipped systems.

Generally speaking Intel, SiS and 100% AMD (no VIA southbridge) work.

Even so Matrox's list isn't 100% reliable. They have the SiS 748 disqualified too, but on my system it works perfectly. Most likely they tested an early board.

Dr. Mordrid

[Marshmallowman]

I have been browseing nforchq for a while with no luck so far.

I found some guys with vaguely related pci problems, eg audio glitching using pro sound carss and the si3112 on the nforce 2 board, they managed to resolve a lot of their problems using pci latency tweaks, which I tried but had no success with. (but I did find a nice win xp/2k latency tool)

I think I will stick with the onboard IDE channels and save up for an external firewire box ,which could have a lot of other handy uses

As it is si3112 on a7n8x with pci capture card has me stumped, luckily the onboard IDE channels work like a charm.

Even so I would have though streaming a precompresed(from broadcast) mpeg 2 stream straight to hdd would not be *that* bandwidth intensive

Really looking forward to buying an amd 64 system next year, hopefully with pci-ex these kind of problems should disappear for good.