NVIDIA’s connector story: EPS vs. 12VHPWR Connector – Unfortunately, good doesn’t always win, but evil wins more and more often (insights)

Those who thought the peculiar small connector was exclusive to NVIDIA’s Founders Edition were mistaken. The GeForce RTX 3090 Ti was a testing ground for the upcoming GeForce RTX 4090 with the new Ada chip. Recall my articles about a 600-watt test vehicle, industrially used by board partners in early 2022, sweating away its potential. This time, partner cards had to use the newly christened 12VHPWR connector. Here’s a glimpse of my MSI RTX 3090 Ti SuprimX:

Notice the new four pins for so-called sideband signals, whose final usage was still debated. Early CEM 5.0 revisions only declared one pin, determining the maximum load between 450 watts (unoccupied) and 600 watts (occupied). Since firmware didn’t recognize this, the RTX 3090 Ti remained at 450 watts, though the boards already had the necessary tracks. Internally, this was used for what I jokingly called “Ada’s Playground.” A small bridge and an engineering BIOS could easily push the GA102 to 600 watts. But this wasn’t for public knowledge. Now, we can discuss it more openly.

Both the header and adapter maintained the familiar profile of individual openings, but the adapter now had a distinct bridge, coding the bottom two pins. Thus, the adapter for the RTX 3090, with its 2x 6+2 pins and up to 300 watts, couldn’t fit the GeForce RTX 3090 Ti with up to 450 watts of power consumption, and vice versa:

Let’s examine a draft drawing from Astron from 2021, which I managed to acquire and have significantly shrunk and digitally altered for obvious reasons. This drawing even shows all three variants! From left to right, we find the final version up to 600 watts without a key, followed by Key 1 for 300 watts and Key 2 for 450 watts. I’ve intentionally removed some details and the exact date:

The scarcity of defective GeForce RTX 3090 Ti units is partly due to their limited production and the fact that 450 watts were realistically feasible. Excluding user error, most issues have been with Asus cards featuring the Flip-Header (rotated by 180°), which I’ll delve into later. Crucially, this 12VHPWR Connector was not developed by Molex but under the leadership of Astron as a sort of derivative.

The extent of licensing acquired is unknown to me, but the 12VHPWR is now effectively an independent fork of Micro-Fit 3.0. Initially, two other companies, Lotes and Amphenol, focused on the headers. Lotes’ drawing, dated early summer 2021, only concerned the 600-watt version without a key. Their connector was named the 12V 2×6 Power Connector, just like Astron’s later-improved 12VHPWR. Oops!

Amphenol (sounding like a diluent) also referenced the 12VHPWR Header in summer 2021, even though their products internally went as Minitek series.

Why Ground Pins Should Be on Top

Looking back, Molex’s header evolution becomes clear. The preferred vertical mounting (and soldering) option positions the opening upwards, with uniformly short pins. This approach is electrically and mechanically optimal, a principle established for decades in both Mini-Fit and Micro-Fit, and recommended for 12VHPWR.

The exception is 90° angled headers, extending sideways from the board. For electrical reasons, power-carrying pins are kept as short as possible, with ground pins placed on top and extended. This is similar in 12VHPWR, although confusingly, the four sense pins are placed below the power-carrying pins, unnecessarily lengthening these profile wires and weakening the header electrically and mechanically. One of my contacts at the original manufacturer humorously quoted “Confucius said…”.

The principle of short power pins has prevailed for years, even opposing the established practice of Flip-Headers in the 6+2 connection (PCI SIG 2×4). Despite the lower failure rate of Mini-Fit connectors on graphics cards compared to the Micro-Fit design, KrisFix reported Flip-Headers failures on AMD cards (albeit rare). Yet, I haven’t seen a destroyed original Mini-Fit Header. Keep this in mind before we revisit the Asus adapter, which adds another layer to this.

 

Thus concludes the transitional model and (preliminary) final version of the 12VHPWR Connector, now included in the connector ‘Wikipedia’ CEM 5.0 without keys. Ok, we now had up to four sideband signals for further definition. But they had to wait, as Intel was also involved, and a centralized, motherboard-controlled power management system enabling smart communication between motherboard, power supply, and graphics card is still non-existent. Next, the four-cable whip arrived—on to the next chapter.