Motherboard with 3 Slot spacing

[vivatobst]

Hey there!
So, I happen to have 2 computers with each a Radeon R9 380 folding. To improve efficiency and perhaps lower my electricity bill, I want to combine these two systems. Therefore I am searching for a motherboard (either a LGA 1155 for my i5-2320 or a PGA AM2+/AM3 for a Phenom 965) with 3 slot spacing between the PCIe x16 slots to allow some airflow.
Right now I do have both cards packed into one system with only 2 slot spacing, but as you can imagine the fans go full jet turbine.
So, if you can support me in finding a motherboards that meet my wishes, that would be appreciated.

[MeeLee]

Instead of that, just get a PCIE x16 riser cable like below, so you can move one of the GPUs away from the other:
https://www.amazon.com/dp/B0731F743X

[vivatobst]

Instead of that, just get a PCIE x16 riser cable like below, so you can move one of the GPUs away from the other:

I was already thinking about that, but I don't want to use one, because I want to put the whole thing in one case.
Water cooling is also out of the question, as there are no longer any cooling blocks to buy for it.

[aetch]

The PCIe riser cable is flexible. It goes on the assumption one of your current motherboards has at least two x16 PCIe slots and there is either a gap further down the motherboard or below the motherboard which the riser's slot can slip into.

What motherboards and cases are you currently using?

[MeeLee]

I used to run my primary GPU in the DVD drive, while my secondary PCIE slot had a GPU mounted in.

[vivatobst]

My AM2+ board is the ASRock A790GHX/128M and its cased in some oooold MCtronics OEM case, which I'm pretty sure has no name. I do have an ASRock ALiveXFire-eSATA2 lying around, too.
(The LGA 1155 board doesn't even have 2 16x PCIe slots)

I didn't know a riser cable is THAT flexible; I heard it breaks easily.

[vivatobst]

I used to run my primary GPU in the DVD drive, while my secondary PCIE slot had a GPU mounted in.

How did you fix it in place? (If even you mounted it at all)

[aetch]

Riser cables, as with anything else, can be that flexible, stiff and fragile.
The hope here was that either there was an unpopulated slot on your motherboard to land the riser's socket into OR your motherboard was a micro-atx where we could simply leapfrog off the end of the board.
Added to that your 2nd x16 slot is actually wired to be only x4. I know at the time there was a bit of an uproar for people who wanted to run dual graphics cards as the 2nd card was hampered by the lack of bandwidth.
I wouldn't recommend a riser cable with your current motherboard.

I'm not sure on the best way forward.

i5-2320 (Sandy-bridge) only has 16 PCIe 2.0 lanes at its disposal so even a motherboard with x8/x8 slots may not get fully used.

Phenom II x4 965 draws more power and runs hotter. Beyond it being PCIe 2.0 standard I don't know how many lanes it has.

I'm tempted to suggest a newer generation of graphics card but in the current climate that's quite a dear ask.

Anyway, chipsets that support the i5-2320 are the P67, Z68 and Z77 (I'm sure there is at least a couple more to cover business chipsets but I cannot remember them just now). A quick glance at ebay shows practically nothing for P67 and Z68.
Z77 is a bit more plentiful.
Boards I would suggest looking at:-
ASrock Z77 Extreme 4
Gigabyte GA-Z77X-UD3H
ASUS Z77 Sabertooth

There's quite a handful of other motherboards there but cannot suggest as their 2nd slot is only a x4 connection.

Caveat - I'm suggesting motherboards which will give x8/x8 connectivity when the primary and secondary slots are populated but don't actually know what you'll get as the processor only has 16 PCIe lanes and needs to reserve some of those lanes for other resources like networking and hard drives.

[aetch]

I used to run my primary GPU in the DVD drive, while my secondary PCIE slot had a GPU mounted in.

What type of cooler was on the card?
How did you circulate air?

[vivatobst]

i5-2320 (Sandy-bridge) only has 16 PCIe 2.0 lanes at its disposal so even a motherboard with x8/x8 slots may not get fully used.

I've been reading conflicting threads where the PCIe lane capacity when computing is discussed. I personally haven't seen any impact in performance for my 380s lately (except for it thermal throttling) or back when I folded on my 2x Quadro 4000s + Phenom 965.

[MeeLee]

It just fit in the DVD drive. didn't mount it, because the PC wasn't portable.
I actually had 2 pcs where I ran em like that.
One, a desktop, with a GTX 1050; it ran only at like 75Watts or so, and only got up to about 65-70C (overclocked).
The case fans were blowing hot air out in the back, I just opened the front lid of the DVD drive, and fresh air came in.
I also had a portable PC where I had an RTX 2060 mounted on top. I had to remove the top casing (open design), as the metal case would become too hot (+80C), but removing the top lid in open design worked fine at 125-129Watts (65-75C).
Whenever I moved it around, I had this shoe box, that was the exact size of the PC, that I would place on top for transporting,
Both had stock coolers. The 2060 I needed to remove the plastic shroud, so the 2 fans were spinning 'without protection'. But it worked for many years.

[aetch]

I've been reading conflicting threads where the PCIe lane capacity when computing is discussed. I personally haven't seen any impact in performance for my 380s lately (except for it thermal throttling) or back when I folded on my 2x Quadro 4000s + Phenom 965.

That's a fair comment.

Normally the discussion surrounding PCIe lane capacity involves a PCIe 3.0 capable processor and even then the evidence is anecdotal at best. Neither of your two processors in question are PCIe 3.0 capable, they're PCIe 2.0 which runs at 1/2 the speed.
Basically, 4 lanes of PCIe 3.0 = 8 lanes of PCIe 2.0

That said, you've tested your cards on a x4 slot and you're happy with it so please ignore my x8/x8 comments.
As to everything else, it's only a suggestion.
You're the person doing the build/upgrade and whatever you decide to do it should be something you're happy with.

[vivatobst]

I think I've settled with the idea to get a new motherboard. I found an ASRock Z77 Pro4 for little money on eBay. It's second PCIe x16 is only x4 capable, but I'm willing to test it out.
Thank you for your kind suggestions

[MeeLee]

x4 speeds are fast enough for an RTX 2060 to RTX 2080. Anything slower will still be impacted, but less from the PCIE bandwidth limitation.
Just make sure you have a PCIE 3.0 or 4.0 compatible CPU, with similar specs for the motherboard.

[vivatobst]

Just make sure you have a PCIE 3.0 or 4.0 compatible CPU, with similar specs for the motherboard.

That is not the plan I'm currenctly going by. My i5-2320 is only PCIe 2.0 capable, just like the Mobo - which is PCIe 2.0 x16 and PCIe 2.0 x4. That is why I will test if it impacts performance at all with my "lower tier" Radeon R9 380's. Will report my results in this very thread