Asus Z86 ProV 16 x slot question

[flong]

Hey quick question guys and/or gals. I have this motherboard:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813131730

The Asus Z68 ProV.

I just have one quick question that is driving me crazy. If I put my XFX 6950 in the first PCI-E x 16 slot (per the manufacturer's recommendation) it covers up the first PCI-E x1 slot so that I cannot use it because the card requires two slots (it is two slots wide).

My question is, if I put the 6950 in the middle (second) PCI-E x 16 slot will the card still have access to a full 16 lanes like it would in the first PCI-E slot? I cannot find the answer anywhere. I think that it will and that the second PCI-E slot only drops to PCI-E x 8 if the first PCI-E slot is occupied by a video card.

If I use the middle (second) PCI-E slot and leave the first one open, then I can use the the two PCI-E x 1 slots for my HDTV card and my Asus Xonar DX 7.1 card.

Thanks for your help with this question - I am still learning about the PCI-E slot "lanes" and the bandwidth terminology.

 

[flong]

Hey you motherboard experts out there - a little help please 🙂

 

[Leaps-from-Shadows]

Since this issue doesn't come up often, I suggest you do it and tell us what the results are. You can use GPU-Z to find out what PCIe rate your graphics card is running at. Just make sure to check GPU-Z while you are stressing the graphics card, as it will switch to a slower PCIe rate when it's idle.

I wish you luck on getting both of the x1 slots to work at the same time. I think their resources are shared on that board, so you may have a problem. Again, it's something you'll have to try out and see if it works.

 

[compulsivebuilder]

You may find that there are only 8 lanes wired to that socket. Just because it is a x16 socket (necessary to allow physically plugging in a graphics card) doesn't mean that there are 16 lanes wired to it. If they did only wire 8 lanes to it, it would make their work simpler in terms of changing from one x16 to two x8 - they'd merely have to switch the 8 lanes.

The manual does state explicitly: "In single VGA card mode, use the PCIe 2.0 x16_1 slot (navy blue) for a PCI Express x16 graphics card to get better performance." - top of page 2-13.

However, you may find that x8 is sufficient to run your 6950 fast enough. It's certainly worth trying.

There definitely is some sharing between resources on that board - you can find it documented on page 2-13 on the manual (in English). The first two graphics slots share with the USB3 controller and the on-board graphics; other than the USB3, that shouldn't trouble you.

The x1 slots do not share with each other, however - the first one shares with the SATA controller and the first PCI slot, while the second one shares with the 1394 controller (that almost no one uses), USB3 1234 point, and the third graphics slot (that you won't be using).

I get the impression (although it's not stated explicitly) that you can only use the second PCIe x1 if you don't use the USB3 1234 - you might want to investigate that, if USB3 is important to you and you must use both x1 slots. I'd be tempted to drop the Xonar card and use the on-board audio rather than sacrifice USB3.

 

[flong]

You may find that there are only 8 lanes wired to that socket. Just because it is a x16 socket (necessary to allow physically plugging in a graphics card) doesn't mean that there are 16 lanes wired to it. If they did only wire 8 lanes to it, it would make their work simpler in terms of changing from one x16 to two x8 - they'd merely have to switch the 8 lanes.

The manual does state explicitly: "In single VGA card mode, use the PCIe 2.0 x16_1 slot (navy blue) for a PCI Express x16 graphics card to get better performance." - top of page 2-13.

However, you may find that x8 is sufficient to run your 6950 fast enough. It's certainly worth trying.

There definitely is some sharing between resources on that board - you can find it documented on page 2-13 on the manual (in English). The first two graphics slots share with the USB3 controller and the on-board graphics; other than the USB3, that shouldn't trouble you.

The x1 slots do not share with each other, however - the first one shares with the SATA controller and the first PCI slot, while the second one shares with the 1394 controller (that almost no one uses), USB3 1234 point, and the third graphics slot (that you won't be using).

I get the impression (although it's not stated explicitly) that you can only use the second PCIe x1 if you don't use the USB3 1234 - you might want to investigate that, if USB3 is important to you and you must use both x1 slots. I'd be tempted to drop the Xonar card and use the on-board audio rather than sacrifice USB3.

What an excellent answer - it helps a lot. I did read the manual cover to cover and you are right it suggests using the graphics card in the first PCI-E slot for best efficiency - whatever that means.

The confusion lies in that Asus calls the second PCI-E slot out as a PCI-E x 16 lanes and then says it goes to 8 lanes if the first slot is occupied. Therefore, one would rationally come to the conclusion that if the first PCI-E x 16 slot is not occupied that the second PCI-E slot would operate at a full 16 lanes - right?

So let me ask the question: I have these three cards to install, what is the best configuration?

1. XFX 6950 (would prefer to use a single PCI-E x 16 slot)
2. Asus Xonar Dx 7.1 sound card - it needs only a PCI-E x1 slot
3. Hauppauge 2250 HDTV card - it needs only a PCI-E x1 slot

A second configuration alternative would be this: what if I put the 6950 in the first slot (which covers the first PCI-E x 1 slot) and then put the Asus Xonar in the second PCI-E x 1 slot and the Hauppauge 2250 in the last (the black) PCI-E x 4 slot (which theoretically would take a third video card). Do you guys think that would be a more efficient setup?

since the first PCI-E x 16 slot does not share bandwidth with the third (the black) PCI-E x 4 slot and the second PCI-E x 1 slot shares only with the black third PCI-E x 4 slot, then it should work right?

The third alternative configuration would be to put the 6950 in the first PCI-E x 16 slot and put one of the cards in the second PCI-E x 16 (which goes to PCI-E x 8) slot and the third card in the black PCI-E x4 slot. Would this alternative be better?

What does it mean when the manual says that the USB 3.0 controller is "shared" with the first PCI-E x 16 slot? If I put the 6950 in the first PCI-E slot, the USB 3.0 plugs will still work right? And will they USB 3.0 plugs work at full speed?

Also, what does it mean that the second PCI-E x 16 slot is "shared" with the USB 1234? Does USB 1234 stand for four USB 3.0 plug-in outlets? If I put the 6950 in the second PCI-E x 16 slot will the USB 3.0 still function at full speed?

It is difficult to understand what Asus means by "shared" bandwidth connections. Does this mean that the "shared" connections will function but not as well or does it mean that using one eliminates the use of another?

Thanks again for your help. I know that this is not as sexy as posting in the "New Build" section, but I really need some help to understand the Asus manual's terminology.

 

[flong]

Since this issue doesn't come up often, I suggest you do it and tell us what the results are. You can use GPU-Z to find out what PCIe rate your graphics card is running at. Just make sure to check GPU-Z while you are stressing the graphics card, as it will switch to a slower PCIe rate when it's idle.

I wish you luck on getting both of the x1 slots to work at the same time. I think their resources are shared on that board, so you may have a problem. Again, it's something you'll have to try out and see if it works.

Yeah, that is why I am researching this now why I can still return the board if necessary. I did my homework before I chose this board and the only other alternative in this price range might have been the AsRock Extreme or a more expensive Gigabyte. With all the damn slots on this board it should be able to support one PCI-E x 16 slot video card and two measly PCI-E x 1 cards. I think I just need to find the right configuration.

I have emailed Asus also; so maybe they can help.

 

[candlelarbra5212]

Just try it.

 

[flong]

Just try it.

It would be nice to know the most efficient layout before my time to return the board is up. Unfortunately, because I had to RMA the first board, I will not have a lot of time to play with different layouts. I am waiting for Newegg to send me a new board - the first board would not post.

This should be a straight forward issue for someone who is familiar with the motherboard terminology that Asus lists in their manual. Unfortunately, Asus does not explain their "sharing" of PCI-E slots very well. They do not explain what happens if you use two slots that "share" with each other or even if you can use two slots that "share" with each other.

 

[flong]

I have a new motherboard question: how do you save the bios to a flash drive with this motherboard? The manual does not explain this - they just tell you to do it.

Second question. when I went through the bios in the first board during setup (the first board worked for a short time before it refused to post), I "saved and exited" the bios but every time I would boot it would ask me to go through "setup" again. How do you get the bios to stop asking you to setup the bios?

Thanks for your help - this is my first build and so it has been challenging. I have spent months researching the best components and what to do.

 

[flong]

Still have two questions guys 🙂

1. How do you save the bios to a flash drive (Z68 Asus PRo V)
2. How do you exit the bios setup so that it doesn't reappear every time to boot the computer?

Thanks

 

[Leaps-from-Shadows]

1. When does the manual tell you to do this? During a BIOS update? I've seen the option to do that when I was updating the BIOS, and I've seen a special option in the BIOS also (on two different boards).

2. Assuming the board is working fine, there is nothing special you need to do -- it will simply save and exit and then boot normally.

 

[flong]

1. When does the manual tell you to do this? During a BIOS update? I've seen the option to do that when I was updating the BIOS, and I've seen a special option in the BIOS also (on two different boards).

2. Assuming the board is working fine, there is nothing special you need to do -- it will simply save and exit and then boot normally.

Thanks for your reply.

The manual doesn't tell you anything specific like that, it simply describes what each section of the BIOS does. Frankly the Asus manual is very terse and does not explain several things overly well.

When my first board was working, it would go to the setup Bios screen every time, but I had two HDDs installed and it would not switch to the HDD with the operating system (Windows 7) as the first choice, even though I had selected that in the BIOS. Errrrrr frustrating.

 

[Leaps-from-Shadows]

The manual doesn't tell you anything specific like that, it simply describes what each section of the BIOS does.

Okay -- where in the manual does it say to save the BIOS to a flash drive? Does it say to do it as part of the install process? Or is it just an option in the BIOS somewhere?

When my first board was working, it would go to the setup Bios screen every time...

Then the board had something wrong with it right away. If a board is working normally, it won't ask you to go through setup automatically like that.

 

[jaquith]

Hmm...I didn't read all of this stuff.

Top / Blue PCIe x1 -> Sound Card {above GPU}
Top / Blue PCIe x16 -> HD 6950
Bottom / Black PCIe x4 -> HDTV Card

 

[flong]

Okay -- where in the manual does it say to save the BIOS to a flash drive? Does it say to do it as part of the install process? Or is it just an option in the BIOS somewhere?


Then the board had something wrong with it right away. If a board is working normally, it won't ask you to go through setup automatically like that.

HI,

The manual says to save the BIOS to a flash drive before updating the BIOS but it doesn't tell you how (at least in a way that I can understand). Maybe they assume this is ABC stuff and doesn't need to be explained. Frustrated, I also Googled it for an explanation but I could not find any satisfactory information with my search.

I sent the board back to Newegg for a replacement, but I am trying to get my ducks in a row before I get the new board back.

Thanks for your help

 

[flong]

Hmm...I didn't read all of this stuff.

Top / Blue PCIe x1 -> Sound Card {above GPU}
Top / Blue PCIe x16 -> HD 6950
Bottom / Black PCIe x4 -> HDTV Card

If I understand Asus's notation right, this configuration would run the PCIE x 4 at one lane (PCIE x 1) and still leave the USB_3 1234 intact so that I would not disable or slow down the USB 3.0 function - is that correct? It is also shared with the 1394 connection but I don't really care about that since I don't think I will ever use it.

The manual also states that the second PCIE x1 (where you suggest the sound card be installed) is "shared" with the SATA controller - will that cause any problems?

The big problem with Asus's description is that it is unclear to me what the consequences are of "shared" connections.

Thank you for your help

 

[jaquith]

The PCIEX16_3 {Black} is shared with the PCIEX1_2/USB3_1234, BUT if you use 'X1 Mode' then only x1 lane is used for the PCIEX16_3. Review manual Pages 2-13 {note the IRQ shared hierarchy} and 3-22. PCIEX1_1 is x1 lane period; this slot is specifically and strategically placed for a 'Sound Card' a sound card uses very little bandwidth.

Placing ANY x1 PCIe in the PCIEX16_2 is NOT advised. If you're filling every SATA port with an SSD then yeah you'll loose some fractional speed.

BIOS:
PCIe Express X16_3 Slot Bandwidth -> X1 Mode
//Turn-Off the 'stuff' you don't use// e.g. Marvell, IEEE 1394, JMB, etc...

 

[flong]

The PCIEX16_3 {Black} is shared with the PCIEX1_2/USB3_1234, BUT if you use 'X1 Mode' then only x1 lane is used for the PCIEX16_3. Review manual Pages 2-13 {note the IRQ shared hierarchy} and 3-22. PCIEX1_1 is x1 lane period; this slot is specifically and strategically placed for a 'Sound Card' a sound card uses very little bandwidth.

Placing ANY x1 PCIe in the PCIEX16_2 is NOT advised. If you're filling every SATA port with an SSD then yeah you'll loose some fractional speed.

BIOS:
PCIe Express X16_3 Slot Bandwidth -> X1 Mode
//Turn-Off the 'stuff' you don't use// e.g. Marvell, IEEE 1394, JMB, etc...

Hi jaquith,

I think that you misunderstood my last post. I was asking questions about the configuration that you had recommended. I did not say that I was putting one of the cards in the PCIE x16_2 slot (but thanks for letting me know that it is not good to put a PCIe x1 card in that slot).

Will the USB 3.0 be affected by putting the HDTV card in the PCIE x 4 (black) slot?

I will be using two HDDs and one SSD and one HDD or SSD in the hot swap bay. The SSD, the hot-swap bay and one HDD will occupy SATA 6 connectors and one HDD will be on a SATA 3 connection.

Note that the PCIE x 1 _1 slot will be blocked by the ATI 6950 because it is two slots wide and it covers the first PCIE x1 slot when it is installed in the first PCIE x 16_1 slot. So the Xonar sound card will have to go in the second PCIE x 1 _2 slot (per your recommendation).

Thanks

 

[jaquith]

Will the USB 3.0 be affected by putting the HDTV card in the PCIE x 4 (black) slot?

Not if you do as I recommended -> "The PCIEX16_3 {Black} is shared with the PCIEX1_2/USB3_1234, BUT if you use 'X1 Mode' then only x1 lane is used for the PCIEX16_3.
BIOS:
PCIe Express X16_3 Slot Bandwidth -> X1 Mode

I will be using two HDDs and one SSD and one HDD or SSD in the hot swap bay. The SSD, the hot-swap bay and one HDD will occupy SATA 6 connectors and one HDD will be on a SATA 3 connection.

2 x SATA 6Gb/s port(s), gray
4 x SATA 3Gb/s port(s), blue

Assuming the SSD is the Primary/OS then don't place in a 'hot swap bay.' There's NO reason to place ANY mechanical HDD {120~140 MB/s} in the {gray/SATA3} ports regardless of it's 'Interface' - a HDD can't saturate the OLD SATA1 150 MB/s let alone a SATA2 of 300 MB/s nor the SATA3 600 MB/s - use the {blue/SATA2} ports. IF the SSD has R/W >300 MB/s use the {gray/SATA3} ports.

Note that the PCIE x 1 _1 slot will be blocked by the ATI 6950 because it is two slots wide and it covers the first PCIE x1 slot when it is installed in the first PCIE x 16_1 slot. So the Xonar sound card will have to go in the second PCIE x 1 _2 slot (per your recommendation).

Sound Card - use the PCIe 2.0 x1_1 {aka PCIEX1_1} THE TOP BLUE x1 Slot closet to the onboard Sound I/O. The HD 6950 as with ALL 'double wide' GPU's the slot is at the top and the width is towards the bottom. You've got it backwards.

 

[flong]

Best answer selected by flong.