A humungous passive copper cooling solution has been causing a stir this week in an interesting little corner of Reddit dubbed HardwareGore. According to Redditor ‘That Desktop User’ (TDU), an approximately 8-pound (around 4kg) block of copper can act as a passable passive cooler – even if you are running an Intel Core i9 CPU.
TDU shared a few facts and figures about their solid cylinder of copper cooling escapade, making this makeshift passive option sound almost practical. For the length of a short computing session, an Intel Core i9 (model undisclosed) was entirely passively cooled by the copper block. The photo below shows that the PC system was fully open-air during this testing process.
During the test run, TDU’s processor idled at 35 degrees Celsius, but temperatures ramped up to 80 degrees Celsius after a benchmark and a stress test that ran for under a minute. Probably the most impressive data nugget shared, though, was that after the stress test was halted, the CPU temperature dived back to its idling temperature within 10 seconds. TDU is the first to admit that they weren't very methodical with their data reading and recording, so please take the above numbers with a pinch of salt.
Some details about the source of this copper block were also shared in the Reddit post. Apparently, the block was once a component within some kind of redundant medical machinery. From the description, it may have acted as a cooler within this medical device, and the holes drilled in the sides are threaded for liquid flow.
Whether TDU will work on adding liquid cooling apparatus to reduce the peak temperatures seen in the preliminary tests remains to be seen. We are also missing a few key data points that would give a better picture of how it performed, including ambient temperatures, thermal paste and block fastening info, more precise data on benchmarks, run times and temperatures .
Despite our misgivings about the whole testing and data recording process, TDU’s Reddit post shows that - even in 2023 – there are still opportunities for DIY shenanigans and homebrew makeshift (or sometimes crazy) solutions for PCs that surprise.
If you are interested in passive CPU cooling and would prefer an off-the-peg solution to cannibalizing old medical machinery, then probably the beefiest choice, which doesn’t require a special case, is the Noctua NH-P1. However, if you want to avoid adding any kind of fan, you will probably be restricted to using this in a system with a 65W CPU. And if you're looking for a more typical and reliable solution, check out our list of the best CPU coolers.
would be much better and smaller if he just stacked a few old copper zalman heatsinks
This is a "I have this big block of copper. Let's try it, see what happens" type of thing.
(Yeah the CPU is protected by the heat spreader, but the rest of the system isn't, I'm just making a point )
But, for running for an hour or so, eh...lets try it.
Also, if it fell over, the CPU probably wouldn't be damaged. The motherboard, however...;)
That way, he'd be able to run the CPU ~10X longer between bursts. Though it'll also take 10X as long for the water to cool back down.
Heat flows from the hotter body to the colder, it does not flow the other way, and if the ambient air temperature is high the "cooler" becomes less efficient. Mistaking thermal conductivity for cooling ability is a common mistake, Aluminium is preferred for "cooler" manufacture due to low cost, workability and low weight. Copper is a better conductor, Silver is the, but both are costly. Fins are vital to increase surface area, but unless the air is forced air by a fan or blower, must be spaced more than 8 to 10mm apart to avoid radiation between fins. Staggered fins to increase turbulence are better than straight ones as they break up any boundary layers that might occur in the air flow. Way back in the 60's and 70's when devices were much less efficient, many useful "heat sinks" were available. Mostly plain aluminium was used, black anodising was offered, but the improvement gained was not cost effective. Industry tried many alternatives
but are in fact convectors.