Concerned about thermal issues with Crossfire 6970s.

[Chaosblade02]

Motherboard: ASRock Z68 extreme 4

CPU: I5 2500k

After market CPU cooler: Cooler master hyper 212 plus

Case: Lian Li PC-A70F Full tower

PSU: Seasonic/SS-850HT Silver

I think that is everything that would be relevant to thermal issues, if any other info is required I can post it.

I plan on running the 2 6970s stock in crossfire, no overclock because why would you even need to overclock them at this time?

This concern started when I looked into my instruction manual that came with my new board, and it gave pictures of Crossfire ATI cards, and it looks like they have only about an inch to spare between them. Now my Board has 3 PCIe X16 connections, 2 are spaced rather close and the other is spaced a little bit farther away. But the instructions given said to use the two slots that were closest together for Crossfire, and the one above was only used for tri-crossfire.

Would I still be able to use the other PCIe X16 port for better spacing and airflow? I am certain I would need a longer crossfire cable, and is there somewhere I can get one?

Just to give a picture of what I am talking about here is a link to a picture of the board.

http://www.asrock.com/mb/overview.asp?Model=Z68%20Extreme4

I am wondering if I could use the PCIe X16 port to the far left and the one to the far right instead of the left and middle ones like the manual suggests?

I am not that concerned about noise, but I would be very concerned if one or both of my GPUs was pulling 80+ degrees celsius on load. I am not concerned about noise of the fans running as long as it isn't extremely overbearing.

This is my first PC I am building from scratch and I want to make sure I get absolutely EVERYTHING right. And this is one of the few concerns I have left.

My build is really close to one of Tom's hardware $2000 builds, minus one SSD, full tower instead of mid tower, I5 2500k instead of an I7 2600k. Other than that it is basically the same. Still around $2000 total after I get the 6970s.

And if I probably need to buy an after market coolers to keep my temps below 80 celsius, anyone got any suggestions of some that work well for a reasonable price? Also they won't do me any good if I can't figure out how to install them so they need to be made to where someone of average tech skill can install with no problems.

 

[3DVagabond]

There's plenty of clearance. Pick cards with good coolers. There's plenty of custom models around now.

 

[ViRGE]

I'm afraid you're reading the manual incorrectly.

Right Slot : PCIe2
Center Slot: PCIe4
Left Slot: PCIe5

From the ASRock Manual:

PCIE2 / PCIE4 (PCIE x16 slot; Blue) is used for PCI Express x16 lane
width graphics cards, or used to install PCI Express graphics cards to
support CrossFireXTM or SLITM function.

PCIE5 (PCIE x16 slot; Blue) is used for PCI Express x4 lane width
graphics cards, or used to install PCI Express graphics cards to support
3-Way CrossFireXTM function.

So only the right and center slots (2 & 4) are full bandwidth slots. The left slot (5) is a limited bandwidth slot.

Now for their CF suggestion

In CrossFireXTM mode or SLITM mode, please install PCI Express x16
graphics cards on PCIE2 and PCIE4 slots. Therefore, both these two
slots will work at x8 bandwidth.

So you should install your cards in the right (2) and center (4) slots. This is consistent with the fact that the board has additional space between the right and center slots, specifically for cooling purposes. This extra space is plenty for cooling purposes, and while you can use the left (5) slot instead of the center (4) slot for the 2nd card, I would not recommend it due to the limited bandwidth of the left (5) slot.

 

[Chaosblade02]

I'm afraid you're reading the manual incorrectly.

Right Slot : PCIe2
Center Slot: PCIe4
Left Slot: PCIe5

From the ASRock Manual:


So only the right and center slots (2 & 4) are full bandwidth slots. The left slot (5) is a limited bandwidth slot.

Now for their CF suggestion

So you should install your cards in the right (2) and center (4) slots. This is consistent with the fact that the board has additional space between the right and center slots, specifically for cooling purposes. This extra space is plenty for cooling purposes, and while you can use the left (5) slot instead of the center (4) slot for the 2nd card, I would not recommend it due to the limited bandwidth of the left (5) slot.

Ok, thanks for the input, and I looked over it again and you are correct.

Do you think I am going to be ok running dual 6970s with stock cooling? No plans on overclocking? I think my Lian Li PC-A70F full tower should keep plenty of air flowing.

I plan on getting 2 of these:

http://www.newegg.com/Product/Produc...82E16814102915

Its a reference chipset. The only reason I don't just flash 2 6950s, is I hear that is too much of a gamble, even though most people have no problems, I don't like trying my luck. And the long term effects of flashing a 6950 card haven't really been determined yet. I want to get a few years out of my cards.

If I have to have my fans running 50% to keep my cards cool and it sounds like a Ford Powerstroke Diesel truck revving up in my living room, I don't care as long as it keeps my cards cool.

 

[ViRGE]

Stock cooling will be fine. You don't need anything special with a motherboard that gives you an extra slot's worth of space.