Multi GPUs - Removing Back Plate

[UaVaj]

there is not much breathing room when multi gpu are sandwiched together so every millimeter of clearance matters.

on the 4gb version of 680. there are vram chips on the back side. they are passively cooled by the back plate. GDDR5 temp are rated to higher than the GPU temp so vram "should" be fine without the back plate, however vram overclocking headroom may suffer without the back plate. so back plate should stay on.

alternative is to replace the back plate. plan to store the original back plate for warranty reasons because the serial number is on it.

planning to cut up the replacement back plate near blower end to allow that extra needed clearance.

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so. is there a public review or private individual with some data pointing out the difference/delta in temperature with the back plate removed and vice versa?

be nice to know such info before pulling out the hacksaw.

 

[BrightCandle]

Not that I know of.

 

[lavaheadache]

Why not just get a motherboard with a larger gap? Surely buying 2 backplates to cut up and worrying about temps is far more troublesome than just buying a different motherboard?

 

[UaVaj]

lavaheadache - already considered that motherboard option. no go for tri sli.

no z77 motherboard is available with slot 1/2 for gpu1, slot 4/5 for gpu2, slot 7/8 for gpu3. leaving 1 slot between each gpu.

also a 1/4/7 sli bridge is far and few too.

 

[lavaheadache]

hmm, I see.. Even so I would try to swap dems 3 680's in favor of 2 780's. would be a more potent system and not too much cash out of pocket.

 

[IEC]

Sorry, but with more than 2 GPUs you're pretty much going to have to water cool to get desirable performance at acceptable noise. Which is pricey but if you already have multiple high end GPUs the price probably isn't going to bother you.

 

[Accord99]

no z77 motherboard is available with slot 1/2 for gpu1, slot 4/5 for gpu2, slot 7/8 for gpu3. leaving 1 slot between each gpu.

Biostar TZ77XE3 and TZ77XE4, but they're exceedingly rare now.

also a 1/4/7 sli bridge is far and few too.

That's true, I'm not sure if the longest bridge would be enough.

 

[rgallant]

no data here
but if you take the back plates off gpu's 2 & 3
-add a 1-2 mm more to the gap with a spacer to spread the space between cards -cards can tilt under their own weight that much so the pci-e slot should be ok.
-add a 120 mm fan [1k rpm] w/ a 1/4" foam fan gasket to the top of the cards - using only the 2 fan corners with tie wraps , would that help feed fans of gpu's 1 & 2 with air.
-also the extra air flow should also cool memory chips.

 

[UaVaj]

looks like me gonna have to be the gineau pig. will take good notes to share when the hacksaw comes out.

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two 780ti is about ~10% faster than three 680.
if it weren't for BF4's 3.4GB vram usage/allocation. 780ti would fit the bill nicely and keeping cool.

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for now 680 tri sli does offer sufficient performance - only if this stock throttling can be kept under control. hopefully a few bandage mods will be enough to hold out until the next upgrade.

 

[lavaheadache]

I'm playing BF4 @ 4k with 2xaa and ultra settings and not hitting the 3gb vram limit

 

[UaVaj]

results are.

on a single gpu or traditional sli (slot 1 n slot 4). removing back plate does NOTHING toward gpu temperature.

as for vram temperature. that is still unknown. no infrared temp sensor. maybe someone else can test. vram should be slightly cooler with the back plate.

on trisli (slot 1, slot 5, slot 7) the middle gpu. there was a solid 2-3C improvement in temp.

.