Limited RTX 5090 LIGHTNING Z gets custom water cooling while retaining its display
Our friend der8auer has modified one of the most expensive GeForce graphics cards available. The MSI GeForce RTX 5090 LIGHTNING Z is limited to 1,300 units and has appeared for around $7,000 on the secondary market. That price would stop most owners from taking the cooler apart.
This card was a bit different case because German system integrator MIFCOM had already removed its factory 360 mm AIO cooler. The company plans to install the card in a system with a full custom liquid loop. Der8auer’s team therefore designed a conversion that retains the original LIGHTNING enclosure and its large integrated display.
Source: Der8auer
The project does not replace the complete factory cold plate. It reuses MSI’s copper base, internal rubber flow guide and external housing. A new cover and terminal connect the existing cold plate to standard custom-loop fittings without turning the card into a conventional water-block model.
Material testing revealed a problem with one of the original AIO components. A plate that appeared to be nickel-plated steel was aluminum covered by approximately 8 to 10 micrometers of electroless nickel. Aluminum and copper can operate together inside a sealed AIO with controlled coolant, but the same combination can cause corrosion in an open custom loop if the nickel coating contains pores or develops damage.
Source: Der8auer
The team replaced this component with a PVD-coated stainless-steel plate and matching terminal. New 1 mm thermal pads and a phase-change thermal interface were also installed. Der8auer did not overclock the card or switch to its more aggressive BIOS because the GPU belongs to a MIFCOM customer.
Source: Der8auer
The converted cooler was tested using an external MO-RA radiator, three D5 pumps and a flow rate of almost 190 liters per hour. At an 800W GPU load, the RTX 5090 LIGHTNING Z initially operated at around 54°C. After almost one hour, the coolant reached approximately 32°C while the GPU remained at 52°C to 53°C, resulting in a coolant-to-GPU difference of about 20°C.
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