Der8auer strips the AIO out of a $7,000 RTX 5090 Lightning and replaces it with a custom loop, achieving 55C at 800W

Q: Does the article indicate the modified block preserves the Lightning’s built-in screen and shroud?

Yes. The article states Der8auer removed the integrated AIO and replaced it with a custom-loop-capable waterblock while preserving the Lightning's built-in screen and shroud.

YouTuber Der8auer modifies an RTX 5090 Lightning's waterblock to support a custom loop, dropping temperatures by 10C at 800W of load.

Aaron Klotz

Tech Reporter

Published Jul 20, 2026 3:50 PM CDT

1 minute & 45 seconds read time

TL;DR: YouTuber Der8auer converted a $7,000 RTX 5090 Lightning by replacing its integrated AIO with a stainless-steel-fitted waterblock for custom-loop use, keeping the screen and shroud. With a 16-fan radiator the mod cut operating temperature from 64C to about 53C at 800W, enabling extra thermal headroom.

Voice: DefaultSpeed

0:00 / 2:44

Popular YouTuber and enthusiast Der8auer has created a new conversion kit for the $7,000 RTX 5090 Lightning that removes the card's integrated AIO liquid cooling system and replaces it with a waterblock capable of being hooked up to a custom loop while preserving the Lightning's built-in screen and shroud. Der8auer showed off the new waterblock in a YouTube video and found the new watercooling system is capable of running the RTX 5090 GPU well below 60C while drawing 800W of power.

Der8auer showed his process of tearing down the RTX 5090 Lightning and modifying the original waterblock to work with a custom loop. During the teardown, the YouTuber showed off the pump inside the integrated AIO and the integrated waterblock, which Der8auer believes was made as cost-optimized as possible based on the waterblock's design.

The waterblock itself features a copper coldplate attached to an aluminum cover on top. The mod involved replacing the aluminum cover with a stainless steel plate featuring the necessary fittings and terminals to hook the GPU up to a custom loop. Furthermore, making the cover stainless steel was critical to ensuring any coolant a customer might use in the modded waterblock will not corrode.

Der8auer tested the modified waterblock with a monster 16-fan radiator and found a significant improvement in thermals compared to the GPU's stock AIO solution. Der8auer referenced TechPowerUp's review of the card for the card's stock temperatures, where they reported 64C operating at 800 watts. Der8auer's modified waterblock performed significantly better, reaching just 53C at 800 watts of power consumption.

Frequently Asked Questions

TweakBot answers common questions about this news using TweakTown's own coverage from this page and related content from our archive. Tap a question to reveal the answer, or type your own below.

Question #1

How did Der8auer modify the RTX 5090 Lightning’s integrated AIO to accept a custom loop?

He tore down the card, then modified the original waterblock by replacing its aluminum cover with a stainless steel plate that included the necessary fittings and terminals to hook into a custom loop. The copper coldplate was left intact, and using stainless steel for the new cover was critical to prevent corrosion from custom coolants.

Answered

Question #2

What materials were changed on the original waterblock and why was stainless steel used for the new cover?

The original waterblock used a copper coldplate with an aluminum cover; Der8auer replaced the aluminum cover with a stainless steel plate that includes the fittings and terminals for a custom loop. Stainless steel was used to ensure any coolant a customer might use in the modded waterblock will not corrode.

Answered

Question #3

Does the article indicate the modified block preserves the Lightning’s built-in screen and shroud?

Question #4

Did Der8auer test overclocking after installing the custom-loop waterblock, and what does the article say about potential OC headroom?

Der8auer did not test any overclocks after installing the custom-loop waterblock. The article says the extra cooling headroom from the beefier solution would likely give the card slightly improved overclocking headroom and better temperatures at 1000 watts, though this was not verified by overclock testing.

Answered

Have a question not listed here? Ask below and TweakBot will answer it.

The mod shows that the RTX 5090 Lightning's waterblock has additional headroom available when paired with a beefier cooling solution. Sadly, Der8auer was not able to test any overclocks, but the extra headroom would likely give the card slightly improved overclocking headroom, as well as better temperatures at 1000 watts as well, which is supported by the card. Granted, the card's default cooling solution is already very good, but for extreme enthusiasts who are willing to go the extra mile and attach a larger radiator to the Lightning compared to what the GPU comes with, an extra 10C could be highly attractive for eking out the best performance from the card.