A modder has shared details of a bold experiment in which they pushed a super-rare Nvidia GeForce RTX 3080 Ti 20GB Founders Edition card beyond its official limits. While performance gains were modest, this engineering sample shows what could have been another RTX 30 flagship.
This is not the first time we’ve heard about the RTX 3080 Ti 20GB, as previous collectors boasted about owning one. The difference with this particular card is that its owner wasn’t afraid to mod it and see what Nvidia’s unreleased GPU can muster. Sharing details on Reddit, the card’s owner, ChintzyPC, said that they acquired the card for $700 from a friend, who had bought two engineering samples for $200 a pop.
Like earlier samples, this card is built around Nvidia’s Founders Edition cooler and PCB, featuring 20GB of GDDR6X memory on a 320-bit bus. For comparison, the retail RTX 3080 Ti version was bundled with just 12GB of VRAM, albeit linked via a larger 384-bit bus. Since this sample didn’t land far from the regular RTX 3080 in synthetic tests, due to its limited memory bus and 350W power limit, ChintzyPC decided to overclock and shunt-mod the card to give it more room to breathe.
The mod focused on boosting the card’s power limits and cooling to avoid throttling and instability. To do so, the Redditor installed additional 10mOhm shunts on the 12-pin and PCIe slot sense rails, but left the memory and controller untouched. This increased the power draw from 390W at stock to about 480W, with brief peaks hitting 555W with a stable overclock. Despite the higher load, the Redditor noted that the power connector’s temperature remained within reasonable margins.
With the power shunts in place, the GPU started outputting more heat than the stock cooler could handle, causing throttling. To counter that, ChintzyPC replaced the original paste with liquid metal and used 0.5mm clamp washers to increase the mounting pressure. The modder also swapped the 12W/mK thermal pads to 20W/mK pads, to transfer more heat from the backside memory to the backplate.
That said, the PCB’s unusual design didn’t make the process easy, as this sample uses a standard Nvidia RTX 3080 Ti Founders Edition cooler and shroud, which doesn’t account for the extra memory chips on the back. Because of this, the memory suffered from high temperatures, reaching 100°C, causing artefacts and instability. To fix this, the modder installed a bunch of add-on heatsinks all over the card, especially on top of the backplate, plus a small fan blowing air over the back side. This resulted in a 31°C GPU idle temperature and around a 94°C memory temperature under heavy RT load, with no throttling to report.
Performance-wise, this mod netted higher scores compared to previous attempts by ChintzyPC, including 5,492 points up from 5,403 in 3DMark Speedway, 5,338 points up from 5,155 in 3DMark Steel Nomad, and 14,337 points up from 13,947 in 3DMark Port Royal. That’s not a massive increase, but it’s clear that Nvidia could have launched a better high-end card in this era, giving users an alternative to the retail RTX 3080 Ti 12GB that could satisfy modern games’ VRAM demands.
