No religion, please! I am not personally advocating either approach (although I have more experience with oil submersion than water cooling).
I would love to hear veterans of each approach weigh in with their thoughts/opinions on these two liquid cooling techniques.
To get things started, here's a laundry list of issues/tradeoffs:
WATERCOOLING (water blocks, tubing, radiators):
- advantages of water cooling over oil:
+ products exist for water cooling (pumps, tubing, waterblocks)
+ mature method: deep knowledge base for technique, materials, etc.
+ cooling applied only to heat-producing components (GPU, CPU, etc)
- Pitfalls unique to watercooling (some surprising):
+ galvanic corrosion can harm pump/waterblocks, leading to flow stoppage and burnout. Avoid dissimilar metals.
+ leaky tube connections can drip on components, leading to a catastrophic short. nonconductive fluid helps.
+ algae growth can suddenly stop flow, leading to burnout. Additives, air-tight loops, semiannual cleanings help.
+ kinked tubing can stop flow. quality tubing and tube management helps.
+ a slipped water block can cease cooling, leading to burnout.
- Requires planning:
+ careful design of cooling loop path.
+ have to choose fluids & additives.
+ system requires maintenance (periodic flushing).
+ water blocks are specialty items (sometimes expensive, can't always be carried over to next system).
+ each water block adds complexity and crowding: cpu, gpu, NB, mobo voltage regulators, DIMMs, gpu RAMs.
+ requires a pump and radiator.
- Still not absolutely silent:
+ you have replaced mobo and GPU fans with a water pump. But even water pumps make noise (so, get a good one, maybe suspend it or use a pad).
+ PSU has not been silenced, unless you water cool that too (some people do).
+ HDDs have not been silenced with watercooling. (they don't have fans, but they still make some noise).
OIL SUBMERSION (mineral oil in aquarium):
- minimal risk of catastrophic cooling failure:
+ only way to lose thermal contact is a leaky tank letting out the oil - in which case your biggest worry is NOT a fried computer.
+ everything gets cooling benefit of oil, including cpu, gpu, NB, mobo voltage regulators, DIMMs, gpu RAMs, etc.
+ no need for pump or radiator: the aquarium walls become a large radiative surface. But a rad could still help.
+ submerged parts are absolutely silent - can submerge everything (even PSU) except HDDs .
+ doesn't require maintenance: mineral oil doesn't evaporate, spoil, or support algae growth.
- pitfalls unique to soil submersion:
+ system harder to move: heavier, cannot be moved quickly, cannot be tipped.
+ spill could be an unholy mess to clean up. Mineral oil doesn't evaporate - so you can't let stuff just "dry out".
+ harder to tinker with system - nasty to attach/detach stuff while submerged; even when removed, components will be forever oily.
+ entire system subjected to hot oil - thus even mobo components that normally do not heat up will feel the 120F op temp.
+ oil can reportedly degrade some plastic components (uncommon).
- still not absolutely silent (similar to watercooled):
+ Might still have a water pump, if you choose to use a radiator (optional - and reduce noice with same methods as with water cooling)
+ PSU has not been silenced, unless you submerged that too (some people do).
+ HDDs cannot be submerged. Period. Have to use other methods for cooling and silencing.