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pault123
06-20-06, 03:16 PM
You know the card i mean, the 'fake' pci-express slot shaped piece of circuit board you put in your 2nd pci-express slot on an SLI motherboard when you only have one card.

Are you guys with the 7950 leaving the shadow card in (might affect the 16x lane sharing?)

or taking it out as the 7950 counts as SLI? (perhaps giving more bus speed to the then 1 pci-express slot being used?)

heatlesssun
06-20-06, 03:28 PM
I have no idea what you are talking about.

I had two 7800 512 GTX, one in each PCIEx16 slot, and when I got my first 7950, I just uninstalled my video drivers, took out the 7800's and put the 7950 in my primary PCIEx16, installed new drivers, and viola.

The 7950GX2 works great, gives me about 98% of the 7800's.

I don't know anything about a "shadow" card.

HighTest
06-20-06, 03:31 PM
There's an inexpensive SLI motherboard out on the market that instead of using an SLI switch jumpers or SLI mode SIM, uses a special PCI-e card that redirects x8 lanes to the first slot to make it a full x16 PCI-e slot.

If I understand the original poster that has one of these boards, you are only using a single PCI-e slot (unless you go Quad mode) and so therefore you'd leave in the "shadow" card so the first slot is a full x16 channel slot.

SH64
06-20-06, 03:47 PM
Dunno about that shadow card , but thanks to HighRest for explaining.

for my mobo (DFI Expert Venus) you can choose the PCI-E bandwidth - either x8 or x16 - via the BIOS so theres no hassle with jumpers or shadow cards. guess i'm lucky ?!

pault123
06-20-06, 04:07 PM
I have the Abit KN8 SLI

From the specs

" NVIDIA SLI Technology
- Two PCI-Express X16 slots support NVIDIA Scalable Link Interface
- Increase bandwidth of the PCI-E bus providing 60x the bandwidth of PCI"

Can someone clarify this means I dont have to worry about going quad in the future and only having x4 speed per card (as in the post http://www.nvnews.net/vbulletin/showthread.php?t=72049 )

It appears I have a full 16x PER slot?


Heres from a review >>

"This board does not use jumpers, neither does it provide an option in the BIOS to enable or disable SLI. Instead, it uses a shadow card."

"To run SLI, simply insert two cards and connect them via the SLI Bridge. But if you wish to run a single card only, it must be placed in the first PCI Express x16 slot and the shadow card must be inserted into the second PCI Express x16 slot, else the board would not boot."

http://i31.photobucket.com/albums/c400/pault123/DSC00052.jpg
http://i31.photobucket.com/albums/c400/pault123/DSC00072.jpg

You can see the shadow card in the above pictures.

Im surprised I thought this was pretty much a standard thing!

shungokusatsu
06-20-06, 04:13 PM
I have the Abit KN8 SLI

From the specs

" NVIDIA SLI Technology
- Two PCI-Express X16 slots support NVIDIA Scalable Link Interface
- Increase bandwidth of the PCI-E bus providing 60x the bandwidth of PCI"

Can someone clarify this means I dont have to worry about going quad in the future and only having x4 speed per card (as in the post http://www.nvnews.net/vbulletin/showthread.php?t=72049 )

It appears I have a full 16x PER slot?


Heres from a review >>

"This board does not use jumpers, neither does it provide an option in the BIOS to enable or disable SLI. Instead, it uses a shadow card."

"To run SLI, simply insert two cards and connect them via the SLI Bridge. But if you wish to run a single card only, it must be placed in the first PCI Express x16 slot and the shadow card must be inserted into the second PCI Express x16 slot, else the board would not boot."


You can see the shadow card in the above pictures.

Im surprised I thought this was pretty much a standard thing!

Can't tell which boards will run at a full 16x per card, I'm still sketchy that any really do at the moment, let alone way older boards supporting it while newer ones don't. The only way to tell is too plug them in and run cpu-z.

HighTest
06-20-06, 04:23 PM
I have the Abit KN8 SLI

Can someone clarify this means I dont have to worry about going quad in the future and only having x4 speed per card (as in the post http://www.nvnews.net/vbulletin/showthread.php?t=72049 )

It appears I have a full 16x PER slot?


Not so, that board uses the nForce4 SLI chipset, not the nForce4 x16 SLI chipset (the X16 chipset has both a north and southbridge, you'll find only the single Northbridge on your board).

How nForce4 SLI works is the following:

2 PCI-E slots that are either both x8 channel when in SLI mode (shadow card removed), or 2 PCI-e slots that are x16 channel on the primary and x1 or x2 channel on the secondary. You cant use the secondary as a x1 or x2 slot as that would remove the shadow card that redirects the x8 channels from that slot to the first one to create the full x16 channels when the shadow board is present.

So you'll have x8 channels PER slot when the Shadow card is removed. You'll receive a performance hit this way if you want to go Quad in the future. When you are finally ready to go Quad, you'll want to upgrade to one of the nForce4 X16 SLI chipset boards (if staying socket 939), or go with the nForce 590 SLI solution (but you'll be AM2 and need a new CPU).

So if the 7950GX2 shares the PCI-E bus as half of what is available to each GPU, you'll only have x4 channels per GPU core :(

But I suspect that this is why they came out with the newer chipsets, the original nForce4 SLI was never designed for more than two graphics cards total.

shungokusatsu
06-20-06, 04:26 PM
Not so, that board uses the nForce4 SLI chipset, not the nForce4 x16 SLI chipset (the X16 chipset has both a north and southbridge, you'll find only the single Northbridge on your board).

How nForce4 SLI works is the following:

2 PCI-E slots that are either both x8 channel when in SLI mode (shadow card removed), or 2 PCI-e slots that are x16 channel on the primary and x1 or x2 channel on the secondary. You cant use the secondary as a x1 or x2 slot as that would remove the shadow card that redirects the x8 channels from that slot to the first one to create the full x16 channels when the shadow board is present.

So you'll have x8 channels PER slot when the Shadow card is removed. You'll receive a performance hit this way if you want to go Quad in the future. When you are finally ready to go Quad, you'll want to upgrade to one of the nForce4 X16 SLI chipset boards (if staying socket 939), or go with the nForce 590 SLI solution (but you'll be AM2 and need a new CPU).

So if the 7950GX2 shares the PCI-E bus as half of what is available to each GPU, you'll only have x4 channels per GPU core :(

But I suspect that this is why they came out with the newer chipsets, the original nForce4 SLI was never designed for more than two graphics cards total.

Then why is my 16x board reading 8x with 2 sets of cards, but 16x when I only have a single 7950 in?

HighTest
06-20-06, 04:40 PM
Then why is my 16x board reading 8x with 2 sets of cards, but 16x when I only have a single 7950 in?

Perhaps you need this? ftp://dlsvr01.asus.com/pub/ASUS/mb/socket939/A8N32-SLI%20Deluxe/A8N321205.zip

Check to see if you already have the 1205 BIOS on your board, if an earlier edition it may not be reporting correctly.

I don't have that board, so I could be wrong. My MSI board had a bios update that mentioned the newer GX2 support in the details, so it may be that several board manufacturers need to update their BIOS files to provide full support correctly.

This BIOS update requirement may be why nVIDIA doesn't "officially" support Quad-SLI yet, it may not function completely up to par without the required updates and they are waiting for the MB makers to catch up.

If the ASUS bios doesn't yet provide the necessary feature you may need to either go for a beta release or wait for a finalized version.

shungokusatsu
06-20-06, 04:46 PM
Perhaps you need this? ftp://dlsvr01.asus.com/pub/ASUS/mb/socket939/A8N32-SLI%20Deluxe/A8N321205.zip

Check to see if you already have the 1205 BIOS on your board, if an earlier edition it may not be reporting correctly.

I don't have that board, so I could be wrong. My MSI board had a bios update that mentioned the newer GX2 support in the details, so it may be that several board manufacturers need to update their BIOS files to provide full support correctly.

This BIOS update requirement may be why nVIDIA doesn't "officially" support Quad-SLI yet, it may not function completely up to par without the required updates and they are waiting for the MB makers to catch up.

If the ASUS bios doesn't yet provide the necessary feature you may need to either go for a beta release or wait for a finalized version.

I have 1205, and on the Asus site it says 1205 adds support for the 7900 and 7950 GX2. I think the findings are correct, its a 32x board, and each card is getting 8x for a total of 32x. Redeemd was saying 4x per card, but that's not the case, if so it would only be a total of 16x, and again this board is 32x with two 16x slots. That's why the other poster was asking about 4x, and in his case with only an 16x slot he'll be running Quad at 4x a card.

HighTest
06-20-06, 04:56 PM
That's why the other poster was asking about 4x, and in his case with only an 16x slot he'll be running Quad at 4x a card.

Which was what I was telling the OP, but the diversion into the BIOS world may be helpful for others that are on an older BIOS setup.

I think he was confused with the ABIT K8N SLI having the same feature set as the ASUS A8N32 Deluxe, when it would have been better to compare it to the ASUS A8N SLI Deluxe.

shungokusatsu
06-20-06, 05:00 PM
Which was what I was telling the OP, but the diversion into the BIOS world may be helpful for others that are on an older BIOS setup.

I think he was confused with the ABIT K8N SLI having the same feature set as the ASUS A8N32 Deluxe, when it would have been better to compare it to the ASUS A8N SLI Deluxe.

Actually I just read up on that board, and it does in fact offer two 16x pcie ports. So if he uses Quad he'll also be running each card at 8x, not 4x.

pault123
06-20-06, 05:11 PM
Thanks for all the input on this :)

Heres the abit site on my mother board

http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=306

which states >>>

2 x PCI Express x16, 3 x PCI Express x1, 2 x PCI slots

Also the two higher boards from mine both appear to have the same SLI specs as mine >>>

http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=275
http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=246

No where can I find mentioned about this nForce4 x16 SLI chipset?

shungokusatsu
06-20-06, 05:21 PM
Thanks for all the input on this :)

Heres the abit site on my mother board

http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=306

which states >>>

2 x PCI Express x16, 3 x PCI Express x1, 2 x PCI slots

Also the two higher boards from mine both appear to have the same SLI specs as mine >>>

http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=275
http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=246

No where can I find mentioned about this nForce4 x16 SLI chipset?

Depending on what you use, one 7950 iwll run at 16x, if you go Quad you'll be limited to 8x per card. I don't believe there are any boards out yet that will run Quad at full 16x.

Stevedroid
06-20-06, 10:51 PM
Looks like you already figured it out, but yes you must have the shadow card in place. That slot has to be filled by either a another video card or the shadow card or your system won't boot regardless of what video card is in the top slot.

Also the KN8-SLI most certainly can not run x16 SLI. The blurb you're referencing is misleading. When it says 2 x PCI Express x16 it's merely talking about the size of the slots, not their capablity in SLI mode. They are full x16 length slots, but the KN8-SLI only runs x8 lanes in SLI just like every other nForce 4 motherboard, sorry.

It's sort of like Via K8T890 motherboards are described as having 4 DDR400 memory slots, which is technically correct, independantly they can all run DDR400 memory, but when all slots are full you can only run at DDR333 speeds.

shungokusatsu
06-20-06, 11:37 PM
Looks like you already figured it out, but yes you must have the shadow card in place. That slot has to be filled by either a another video card or the shadow card or your system won't boot regardless of what video card is in the top slot.

Also the KN8-SLI most certainly can not run x16 SLI. The blurb you're referencing is misleading. When it says 2 x PCI Express x16 it's merely talking about the size of the slots, not their capablity in SLI mode. They are full x16 length slots, but the KN8-SLI only runs x8 lanes in SLI just like every other nForce 4 motherboard, sorry.

It's sort of like Via K8T890 motherboards are described as having 4 DDR400 memory slots, which is technically correct, independantly they can all run DDR400 memory, but when all slots are full you can only run at DDR333 speeds.

Sorrt about that, then Paul will be running at 8x, 4x if he goes Quad.

HighTest
06-21-06, 12:01 AM
No where can I find mentioned about this nForce4 x16 SLI chipset?

Here you go, when in doubt always go to the source (of the chipsets that is) ;)

http://www.nvidia.com/page/nforce4_family.html

Note the differences between the nForce4 SLI and nForce4 SLI X16, the SLI has only 20 channels possible for PCI-e the SLI X16 has 38 for the AMD CPUs.

x16 + x16 |= 20 channels, so unless you have the SLI X16 your chipset is physically not possible of supporting two x16 channel PCI-e slots at the same time. You need 32 channels minimum for SLI X16 in each slot and that is only met by the higher end chipset which comprises of two chips versus the single chip for nForce4 SLI.

Note from the description of the motherboard at http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=306

Chipset
- NVIDIAŽ NF4 SLI Single Chipset

This indicates on the single chip so it only has 20 channels of PCIe available total. x16 to the PCI-e x16 slots (So it's either a single slot at x16 channels or two x8 channel slots that are capable of holding x16 PCI-e cards but the extra channels are not available).

Hopefully this helps explain the differences in chipsets and the lack of the SLI X16 chipset on the K8N SLI board.

shungokusatsu
06-21-06, 12:07 AM
Here you go, when in doubt always go to the source (of the chipsets that is) ;)

http://www.nvidia.com/page/nforce4_family.html

Note the differences between the nForce4 SLI and nForce4 SLI X16, the SLI has only 20 channels possible for PCI-e the SLI X16 has 38 for the AMD CPUs.

x16 + x16 |= 20 channels, so unless you have the SLI X16 your chipset is physically not possible of supporting two x16 channel PCI-e slots at the same time. You need 32 channels minimum for SLI X16 in each slot and that is only met by the higher end chipset which comprises of two chips versus the single chip for nForce4 SLI.

Note from the description of the motherboard at http://www.abit-usa.com/products/mb/techspec.php?categories=1&model=306



This indicates on the single chip so it only has 20 channels of PCIe available total. x16 to the PCI-e x16 slots (So it's either a single slot at x16 channels or two x8 channel slots that are capable of holding x16 PCI-e cards but the extra channels are not available).

Hopefully this helps explain the differences in chipsets and the lack of the SLI X16 chipset on the K8N SLI board.

The ASUS A8N32-SLI is a NF4x16 chipset correct?
http://usa.asus.com/products4.aspx?l1=3&l2=15&l3=0&model=744&modelmenu=1

I believe it is, "NVIDIA nForce™4 SLI X16 chipset". One member kept persisting it was only running at 4x per card.

HighTest
06-21-06, 12:22 AM
The ASUS A8N32-SLI is a NF4x16 chipset correct?
http://usa.asus.com/products4.aspx?l1=3&l2=15&l3=0&model=744&modelmenu=1

I believe it is, "NVIDIA nForce™4 SLI X16 chipset". One member kept persisting it was only running at 4x per card.

The ASUS A8N32-SLI is an NF4x16 chipset setup. But I'm trying to answer the original posters question about his ABIT K8N SLI. I think the OP is getting confused with the nForce4 SLI X16 chipset motherboard owners jumping into the thread and adding to his confusion.

As to the x4 channels, that's per GPU and on an nForce4 SLI platform where only two x8 channel PCI-e slots are logically available in SLI mode even though physically they are x16 layout. That would be x8 per card with each card dividing the channels available to each GPU, thus the x4 channels.

Lucky owners of the newer motherboards with the nForce4 SLI X16 chipset have a full x16 per PCI-e slot and when devided between each GPU that ends up as x8 per GPU on the newer boards. x8 per GPU is more than sufficient (and is also all that is capable until newer x24 or x32 PCI-e slots are released), x4 per GPU steals the performance that the card could be capable of.

The original poster, if he leaves his "shadow" card connected will have the full x16 PCI-e slot available to his 7950GX2 card and thus x8 channels "per GPU" but only when using a single card.

Dual 7950GX2 setups were really intended only for the newer nForce4 SLI X16 and nforce590 chipsets only and is the reason that nVIDIA only supports Quad SLI officially from some system integrators that have those necessary requirements met (newer chipsets + proper BIOS support). Quad SLI is technically capable on any of the SLI rigs, just performance would be robbed when the older chipset is used.

shungokusatsu
06-21-06, 12:55 AM
The ASUS A8N32-SLI is an NF4x16 chipset setup. But I'm trying to answer the original posters question about his ABIT K8N SLI. I think the OP is getting confused with the nForce4 SLI X16 chipset motherboard owners jumping into the thread and adding to his confusion.

As to the x4 channels, that's per GPU and on an nForce4 SLI platform where only two x8 channel PCI-e slots are logically available in SLI mode even though physically they are x16 layout. That would be x8 per card with each card dividing the channels available to each GPU, thus the x4 channels.

Lucky owners of the newer motherboards with the nForce4 SLI X16 chipset have a full x16 per PCI-e slot and when devided between each GPU that ends up as x8 per GPU on the newer boards. x8 per GPU is more than sufficient (and is also all that is capable until newer x24 or x32 PCI-e slots are released), x4 per GPU steals the performance that the card could be capable of.

The original poster, if he leaves his "shadow" card connected will have the full x16 PCI-e slot available to his 7950GX2 card and thus x8 channels "per GPU" but only when using a single card.

Dual 7950GX2 setups were really intended only for the newer nForce4 SLI X16 and nforce590 chipsets only and is the reason that nVIDIA only supports Quad SLI officially from some system integrators that have those necessary requirements met (newer chipsets + proper BIOS support). Quad SLI is technically capable on any of the SLI rigs, just performance would be robbed when the older chipset is used.

That explains alot, thats why all 7950 owners with just a single 7950 are getting 16x with cpu-z, and those with Quad are getting 8x. I'm guessing those who have a single 7950 and are getting 8x have older chipsets.

pault123
06-21-06, 01:38 PM
Thanks hightest you really know your stuff :)

"x8 per GPU is more than sufficient"

That comforts me in the knowledge i'm giving my 7950 everything it neads to perform at its peak.

The last thing I wanted was a very powerful card which cant perform properly due to an insufficient motherboard.

I'll stay with 1x 7950 for the time being then.

Oblivion runs amazing on it, everything maxed out and fps smooth and silky.