128GB RTX 5090 prototype spotted with GDDR7X memory

Seller claims to have a 128GB RTX 5090 prototype, and they are selling it for $13,200

I_Leak_VN has spotted a listing for an alleged 128GB RTX 5090 GPU prototype, using GDDR7X memory to deliver higher memory capacities than any existing RTX 5090 model. This prototype is allegedly an Nvidia-made Engineering Sample (ES), not a modified RTX 5090 GPU. Several publications have already falsely reported that this GPU has had a “capacity mod”.

Why give an RTX 5090 GPU 128GB of memory? AI! AI workloads benefit from large memory pools, and having more than 100GB of VRAM on a graphics card is highly desirable. Nvidia’s standard RTX 5090 has 32GB of VRAM. While this is plenty of memory for gaming workloads, it’s not that large when you consider the size of LLMs that users may want to run locally.

Nvidia has built a 96GB GPU called the RTX PRO 6000, and it uses the same silicon as Nvidia’s RTX 5090 (but with fewer disabled elements). If Nvidia could create a 128GB GPUs, one has to wonder why Nvidia hasn’t commercialised that.

Additional notes: He says it's a prototype GDDR7X VRAM, so everyone pay attention – it's just a prototype, not the closest to anything on the market. It's intended to be the ES version that's "somewhat" similar to the Titan Ada version that everyone has seen before.

— I_Leak_VN (@I_Leak_VN) September 7, 2025

Is this 128GB RTX 5090 too good to be real?

Honestly, there are several aspects of this GPU listing that raise questions. For starters, to have 128GB of VRAM, this GPU needs to have 4GB (32Gb) memory modules. Currently, no memory manufacturers produce GDDR7 memory chips with these memory capacities. If they did, they probably would have issued a press release to describe this “world first”.

While this chip claims to use GDDR7X memory, it is hard to believe that this memory type already exists. After all, we have only just started to see GDDR7 memory in graphics cards, and today’s GPUs don’t use the fastest GDDR7 memory available. Another thing to note is that GDDR-X memory chips tend to focus on bandwidth rather than memory capacity. It feels like it is too soon to jump from 3GB (24Gb) GDDR7 to 4GB (32Gb) GDDR7X.

Honestly, this 128GB RTX 5090 GPU feels like a scam. Modded GPUs exist, but this “prototype” seems too good to be true. Unless we see memory manufacturers talk about 32Gb (4GB) VRAM chips in the near future, there’s little reason to believe that this GPU really exists.

You can join the discussion on Nvidia’s rumoured 128GB RTX 5090 prototype on the OC3D Forums.