Problem using 3 card system in a mixture of PCI-x and PCI slots

[sunburst79]

BTW I just checked with Bob and he said his slots were set at 133Mhz....So it looks like I may be wrong on the speed thing. Although he was only running 2 cards and both in the PCI-X slots. It may be when you mix slot types you need to lower the bus speed. All I'm really suggesting is trying another PCI-X speed if 133 isnt working.

[DigitalMetal]

Im very interested to know if anyone has any concrete figures for how much pci bandwidth a PTHD card actually needs,
Then we can see how much bandwidth a slot or a PCI bus has available & know whether there is a bottleneck somewhere,
This may be the cause of not being able to add a 3rd card in the supermicro board and why i struggled with my Gigabyte board that x9blade has.

If my expansion chassis and the single PCIX slot that it is plugged into has enough bandwidth to run my 3 cards without problems then it must be under the quoted figures i posted previously.

x9blade i dont really track with my system i mainly import and mix with it but i dont really have any latency to speak of, i usually run my buffer size at 512 even when maxing out 3 cards with plugins while mixing.

[sunburst79]

Originally Posted by DigitalMetal

Im very interested to know if anyone has any concrete figures for how much pci bandwidth a PTHD card actually needs,
Then we can see how much bandwidth a slot or a PCI bus has available & know whether there is a bottleneck somewhere,
This may be the cause of not being able to add a 3rd card in the supermicro board and why i struggled with my Gigabyte board that x9blade has.

If my expansion chassis and the single PCI-X slot that it is plugged into has enough bandwidth to run my 3 cards without problems then it must be under the quoted figures i posted previously.

x9blade i dont really track with my system i mainly import and mix with it but i dont really have any latency to speak of, i usually run my buffer size at 512 even when maxing out 3 cards with plugins while mixing.

You would have to go find a block drawing of the chipset but as I recall the PCI-X lanes on the old 975X were a side port (meaning separate) from the regular PCI bus. I have no idea how they are handling it with the newer socket 1156 stuff. I sent a email to a HD3 (or HD4) user on the old ASUS P5DG2 WS but he can't remember and is currently snowed in at a pub and can't get to the studio to check....Poor boy.

I know the PCIe cards are only PCIe x1 but that doesn't mean they are using the whole band width. The old ASUS P4C800-E Deluxe held 5 HD cards in 5 regular 32bit slotz and never suffered from bandwidth issues that I'm aware of.

[DigitalMetal]

Originally Posted by sunburst79

the old ASUS P5DG2 WS

Thats what i have now, (abiet the Pro version)
My Magma chassis with my HD3 is connected to one of the PCIX slots,
Then i have a TC Powercore MK2 in the other PCIX
A Powercore Element in a PCI slot
And a Powercore firewire, a Liquid Mix 32 and an SSL Duende firewire,

All running very well together so i cant complain about the 975X Chipset at all,
But i couldnt get it all to work in my Gigabyte P35 board so i sold it off,

Im just trying to get as much info as possible ready for when i need more CPU/FSB Power in the future,

The main reason i bought the chassis was that i was more and more aware of PCIX getting killed off and i cant afford a PCIe cards upgrade.
I just hope it was a worthwhile move for me :)

[RyanC]

Lets do the math. . .

132MB/s (x 1mil)=132,000,000B/s (x8- 8 bits in a byte)=1,056,000,000bit/s

a 24 bit stream at 44.1 uses 1,058,400bit/s (44100x24).

So a fully realized 32/33 PCI bus should Be capable of roughly 1000 tracks of 24/44.1. . . or 1000 TDM voices (997 to be exact) @ 44.1.

Of course it is a 32 bit conduit, so most likely the 24 bit data goes through with one empty byte so each voice uses 1,411,200bits/s (look familiar?). Which cuts us down to 748 TDM voices. Also PT would need to send lots of other stuff to the cards too, like automation data etc. Also a PCI bus is unlikely to be capable of 132MB/s in reality. Realistically something more like 100MB/s, but regardless 32/33 should be more than enough to realize PTHD's highest voice settings.

In older boards, there was loads of other stuff sharing the PCI bus, so this was problematic, but now that almost everything is either directly connected to the NB or SB on the board, or via PCIe (all the integrated stufff), the PCI slots should be more or less alone.

You should not run your HD cards higher than 33mhz, if you did you would be overclocking them and could expect to fry one (probably almost instantly if the bus was running at 133). That said I doubt your mobo would actually let you do that. But regardless you should either have it set to 33 or auto.

Anyone try that gigabyte board with the 4 PCI slots yet?

[sunburst79]

Originally Posted by RyanC

Lets do the math. . .

132MB/s (x 1mil)=132,000,000B/s (x8- 8 bits in a byte)=1,056,000,000bit/s

a 24 bit stream at 44.1 uses 1,058,400bit/s (44100x24).

So a fully realized 32/33 PCI bus should Be capable of roughly 1000 tracks of 24/44.1. . . or 1000 TDM voices (997 to be exact) @ 44.1.

Of course it is a 32 bit conduit, so most likely the 24 bit data goes through with one empty byte so each voice uses 1,411,200bits/s (look familiar?). Which cuts us down to 748 TDM voices. Also PT would need to send lots of other stuff to the cards too, like automation data etc. Also a PCI bus is unlikely to be capable of 132MB/s in reality. Realistically something more like 100MB/s, but regardless 32/33 should be more than enough to realize PTHD's highest voice settings.

In older boards, there was loads of other stuff sharing the PCI bus, so this was problematic, but now that almost everything is either directly connected to the NB or SB on the board, or via PCIe (all the integrated stufff), the PCI slots should be more or less alone.

You should not run your HD cards higher than 33mhz, if you did you would be overclocking them and could expect to fry one (probably almost instantly if the bus was running at 133). That said I doubt your mobo would actually let you do that. But regardless you should either have it set to 33 or auto.

Anyone try that gigabyte board with the 4 PCI slots yet?

Thanks for the math So PCI bus bandwidth shouldn't be an issue assuming theres no other interupts.

[sunburst79]

Originally Posted by DigitalMetal

Thats what i have now, (abiet the Pro version)
My Magma chassis with my HD3 is connected to one of the PCIX slots,
Then i have a TC Powercore MK2 in the other PCIX
A Powercore Element in a PCI slot
And a Powercore firewire, a Liquid Mix 32 and an SSL Duende firewire,

All running very well together so i cant complain about the 975X Chipset at all,
But i couldnt get it all to work in my Gigabyte P35 board so i sold it off,

Im just trying to get as much info as possible ready for when i need more CPU/FSB Power in the future,

The main reason i bought the chassis was that i was more and more aware of PCIX getting killed off and i cant afford a PCIe cards upgrade.
I just hope it was a worthwhile move for me :)

Yeah thats the one. I got the name wrong. Its a bit of a tougue twister. And I was going from memory. Bob Nagy, NickH, and Guitarzan all are running the same board. Last I knew NickH was running HD3 and thinking about HD4. Its a good board.

[DigitalMetal]

Thanks for the Maths !

Is it really that simple?

[kirkgale]

Tested dumbing down the PCI-x slots to 33 Mghz (since the Auto setting wasn't curing the problem.

No change in behavior (i.e., even opening, closing or dragging a VI window causes "PT not responding" messages and freezing...can't even exit the program)....just using 2 cards in the PCI-x slots on Auto is stable heaven...

Armed with the "new" info that these PCI-x cards are really PCI cards, I am ready to change motherboards to be able to run more than HD2.

Anyone know of an LGA Socket 1366 Board w 3 adjacent PCI slots...?

[x9blade]

i am running the gap35 s3g with 4 cards at times with 5 cards, it works!!!