Enthusiast zone: Famed hardware overclocker Roman "der8auer" Hartung has modified an RTX 5090 Lightning graphics card with a custom watercooling setup, swapping the original AIO for a stainless-steel fitted waterblock. The conversion kit reportedly lowered operating temperatures by around 11 degrees Celsius at 800W under full load.
The modified waterblock, once hooked up to the PC's custom water-cooling loop, brought the operating temperature of the MSI RTX 5090 Lightning Z down from 64 degrees to around 53 degrees. That result was measured at 800W under full load, though der8auer believes it would hold up similarly even in the card's 1000W Extreme Performance mode.
The modification went smoothly for the most part, but the team still ran into a few unwanted surprises, including an aluminum plate coated with electroless nickel inside the original AIO. While electroless plating is specifically designed to prevent corrosion, Hartung and his team replaced it with a PVD-coated stainless steel plate, since aluminum can still corrode in an open water-cooling loop despite the coating.
Aside from the new loop and fittings, the modded RTX 5090 Lightning retained most of its stock components, including the built-in screen and external housing. der8auer also left the card's cold plate, copper base, and internal rubber flow guide untouched. They did, however, install new 1mm thermal pads and a phase-change thermal interface.
Once the modification was complete, the new setup was tested with a high-performance external MO-RA radiator from Watercool, with three D5 pumps pushing almost 190 liters of water per hour. The card pulled around 800W on average under full load, yet GPU temperature held steady at 53 degrees even after an hour of gaming, while the coolant reached just 32 degrees Celsius.
der8auer didn't disclose the total cost of the modification, but online speculation puts it around $8,000 on top of the card's purchase price. Given the steep costs and the level of expertise required, the mod isn't intended for general gamers – but it's a fun experiment for modders and DIY hobbyists nonetheless.
The MSI RTX 5090 Lightning Z is an exclusive high-performance graphics card limited to just 1,300 production units. Built on Nvidia's Blackwell architecture, it features an integrated 8-inch LCD display, a custom reinforced PCB with 3oz copper, and integrated AIO water cooling. It carries an official MSRP of $5,000, though it often sells for $7,000 to $8,000 on the secondary market.