The curious tale of the missing eight: Some Nvidia RTX 50-series cards are shipping with missing ROPs in the GPU, Nvidia says only 0.5% of all cards are affected

pcgamer.com:

Nvidia's latest gaming GPU, the RTX 50-series, hasn't enjoyed a flawless launch. With high prices, low stock, and concerns over melting connectors, black screens, and unstable cards, it's transpired over the weekend that there is one more thing to fret about: does your Blackwell GPU have its full complement of ROPs?

The discovery of the missing ROPs was first reported by TechPowerUp, which relayed a post by one of its forum users. That person noticed their new RTX 5090 showed it only had 168 ROPs instead of 176. TechPowerUp then checked one of its 5090 cards and discovered the same issue and it also happened to be a card that performed slightly worse than other models when tested.

Render output pipelines, or raster operation pipelines, render backends, render output partitions, or just ROPs for short, are fundamental units in every GPU. Think of them as specialised load/store units that read and write pixel information into a graphic's card VRAM. They also handle operations such as blending and certain types of antialiasing.

Prior to its Turing architecture, ROPs used to be directly attached to a slice of L2 cache and a memory controller, but these days, they're embedded within discrete sections of the GPU called GPCs (graphics processing clusters). In every GPC, you'll find two banks or partitions of eight ROPs, for 16 in total.

An RTX 5090 comprises 11 GPCs so it should have 11 x 2 x 8 = 176 ROPs. Likewise, an RTX 5080 and RTX 5070 Ti, with 7 and 6 GPCs, will have 112 and 96 ROPs respectively. Except for those unlucky few who have bought a shiny new Blackwell GPU that has one ROP partition disabled.

As more reports about RTX 50-series cards with missing ROPs began to appear over the weekend, The Verge contacted Nvidia about the issue and was told that: "We have identified a rare issue affecting less than 0.5% of GeForce RTX 5090 / 5090D and 5070 Ti GPUs which have one fewer ROP than specified. The average graphical performance impact is 4%, with no impact on AI