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koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
reply to sk1939

Re: Using only the second PCIE x16 same speed ? for video card

To expand on sk1939 See Profile's post mentioning the GA-Z77X-UD3H -- meaning I'm trying to make it more clear for you, me See Profile -- so please read slowly/thoroughly again --

First, see the zoomed in picture of the GA-Z77X-UD3H board and read the silkscreening labels on each of the slots (either above or along the edge of the slot). I'll describe each slot to you, from RIGHT TO LEFT:

PCIEX1_1 -- PCIe x1 slot, supporting up to x1 speed
PCIEX16  -- PCIe x16 slot, supporting up to x16 speed
PCIEX1_2 -- PCIe x1 slot, supporting up to x1 speed
PCIEX1_3 -- PCIe x1 slot, supporting up to x1 speed
PCIEX8   -- PCIe x16 slot, supporting up to x8 speed
PCI      -- standard PCI slot
PCIEX4   -- PCIe x16 slot, supporting up to x4 speed
 

We assume your graphics card requires one PCIe x16 slot and takes up 2 physical backplane/chassis slots (this is common today), which means if it was installed in PCIEX16, it would physically block PCIEX1_2 from being used.

And if you install a PCIe x1 card in PCIEX8, your PCIEX16 slot drops to x8 speed, which you don't want either.

Following so far?

This board will meet your requirements without any speed loss/degradation if you do the following:

* Install graphics card in PCIEX16
* Install PCIe x1 card in PCIEX1_1
* Install PCIe x1 card in PCIEX1_3
* Install PCIe x1 card in PCIEX4

How does this work / why this configuration?

1. By leaving slot PCIEX8 empty, this ensure PCIEX16 stays at x16 speed,
2. Never populate slot PCIEX4 with a x2, x4, x8, or x16 card -- otherwise you will disable/turn off the PCIEX1_1, PCIEX1_2, and PCIEX1_3 slots, since they share bandwidth with the PCIEX4 slot.

Make sense?

Finally, I should note this same configuration will work on the GA-Z77X-D3H (note the model string difference) too.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.

sk1939
Premium
join:2010-10-23
Mclean, VA
kudos:10
To speak on the difference between the D3H and the UD3H, it boils down to having eSATA ports or not, that's it.


me

join:2002-12-08
Iapetus

1 edit
reply to koitsu
Thanks that clears up some things for me.

Between D3H and the UD3H I think UEFI BIOS is also a difference.

Edit:
Placing anything including PCEe x1 on PCIEX8 will affect PCIE16?


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
said by me:

Between D3H and the UD3H I think UEFI BIOS is also a difference.

Incorrect:

GZ-Z77X-UD3H rev 1.0 -- »www.gigabyte.com/products/produc···=4153#ov
GA-Z77X-D3H rev 1.0 -- »www.gigabyte.com/products/produc···=4144#ov
GA-Z77X-D3H rev 1.1 -- »www.gigabyte.com/products/produc···=4325#ov

You can see if you scroll down the page, all of them are completely UEFI-based ("UEFI DualBIOS"). There is no classic BIOS for any of these boards.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


me

join:2002-12-08
Iapetus

2 edits
I went with the GA-Z77X-D3H rev 1.0 without knowing about that v1.1 is available.
This model has more SATA connections (which I may need). For $40 dollars less after rebate, I decided against UD3H.

Version 1 and 0 are basically the same except for a PCIe 3.0 issue.

GA-Z77X-D3H rev 1.0
1 x PCI Express x16 slot, running at x8 (PCIEX8)
* The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.
(The PCIEX16 and PCIEX8 slots conform to PCI Express 3.0 standard.)
* PCIE Gen.3 is dependent on CPU and expansion card compatibility.

GA-Z77X-D3H rev 1.1
1 x PCI Express x16 slot, running at x8 (PCIEX8)
(The PCIEX16 and PCIEX8 slots conform to PCI Express 3.0 standard.)
* Whether PCI Express 3.0 is supported depends on CPU and graphics card compatibility.
* The PCIEX8 slot shares bandwidth with the PCIEX16 slot. When the PCIEX8 slot is populated, the PCIEX16 slot will operate at up to x8 mode.


Also 1 x 8-pin ATX 12V power connector for the UD3H
and 4 for D3H. (not sure if this will affect overclocking)

Comparison chart
»www.gigabyte.com/products/compar···153,4144

These would have been nice to have on my board
1 x power button
1 x reset button
1 x Clear CMOS button
1 x Voltage Measurement Points
1 x BIOS Switch


me

join:2002-12-08
Iapetus
reply to koitsu
said by koitsu:

How does this work / why this configuration?

1. By leaving slot PCIEX8 empty, this ensure PCIEX16 stays at x16 speed,
2. Never populate slot PCIEX4 with a x2, x4, x8, or x16 card -- otherwise you will disable/turn off the PCIEX1_1, PCIEX1_2, and PCIEX1_3 slots, since they share bandwidth with the PCIEX4 slot.

This limitation of the PCIEX4 slot leads me to my main question and concern. Can I use the second PCIEx16 slot for my video card without a reduction in speed. I will leave the first PCIEx16 slot empty. This way I have 3 PCIe x1 slots free.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
said by me:

Can I use the second PCIEx16 slot for my video card without a reduction in speed. I will leave the first PCIEx16 slot empty. This way I have 3 PCIe x1 slots free.

Yes, you can absolutely do that. I have confirmation of that working correctly/reliably from a colleague of mine in Sweden whose "main" PCIe x16 slot has gone bad (I believe one of the pins in the slot has somehow gotten out of place/bent), so he uses the 2nd PCIe x16 slot without any repercussions. Just make sure you keep the 1st PCIe x16 slot open.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


me

join:2002-12-08
Iapetus
OT. A friend from Sweden just left my house to head back home...

The fact that they label it PCIE8 makes me wonder although someone already mentioned its not a factor at this time.

Any recommendation on software that displays this information. I will give SIW a try later.


koitsu
Premium,MVM
join:2002-07-16
Mountain View, CA
kudos:23
said by me:

OT. A friend from Sweden just left my house to head back home...

The fact that they label it PCIE8 makes me wonder although someone already mentioned its not a factor at this time.

Any recommendation on software that displays this information. I will give SIW a try later.

I'm sorry, I gave you wrong information -- see, even for me it's hard to keep track!

The 2nd PCIe x16 slot only runs at up to x8 speed. So your x16 card will function/work fine, but will be running at x8 speed. (If you look closely at the slot, you'll see it only has pins for up to x8). If that's not an issue for you, great, problem solved. But if you want your card to run at x16 speed, you'll need to follow what I said above.
--
Making life hard for others since 1977.
I speak for myself and not my employer/affiliates of my employer.


me

join:2002-12-08
Iapetus
Ok I guess I will make due with the 2 PCIe x1 and the PCIe x4.
BTW. My plan is to connect HDMI streaming cards to connect cameras and use software as a switch. At this point up to 3 cameras is enough.