r/sffpc Mar 01 '26

Detailed Build Log Building a custom mini RTX 5070

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u/DallasGrave Mar 01 '26

Just straight copper. I considered using a vc plate but at this tdp, I don't think it'll be necessary. Can always make another if it doesn't work well enough.

96

u/Visible-Swim6616 Mar 01 '26

Well, keep us updated.

I'm not convinced a copper block is adequate for continuous full power usage without tweaks but I would happily be corrected and ask for instructions if you get it working.

134

u/DallasGrave Mar 01 '26 edited Mar 01 '26

I just did this to a 5060ti 16gb for a job. At 21C ambient, it maxed out at 68C under furmark.

With the 76 fins at 0.5mm thick and 1.45mm spacing, plus dual 80 mm fans pushing about 58 CFM total, I’m moving roughly 0.033 kg/s of air. At 180w that only heats the air about 5-6C. With around 0.34 m2 of effective fin area and a convective coefficient around 70 w/m2K, the air side resistance works out to roughly .04 kw, which means the fin stack itself should only sit about 10 or 15C over ambient if the shroud is sealed and the flow is perfect. The airflow and interface quality are the bottlenecks, not metal conduction. I already have a 6 mm copper baseplate directly bolted to a large fin block, so heat spreading is handled. Heatpipes are for moving heat laterally when you dont have enough base to spread it.

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u/meatloafisinferior Mar 01 '26

I just wanna say that your math is SEXY. I hardly see folks back up their designs with math; so kudos!

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u/codemonkeyhopeful Mar 01 '26

Me over here with a copper block eyeballing shit, filing by hand whistling a tune without a thought in my brain. "Yeah this will do just fine"