RTX 4090 and 4080 PCB pictured and more details rumored
Unlimited power! And a new space heater
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Igor’s Lab has received images from his sources of the unpopulated reference board for the RTX 4090 and 4080. With a couple of more sources confirming the layout of the reference PCB schematic there is a good chance this is close to the final design. Igor also finds confirmation that the RTX 3090 Ti is likely a test run for the Lovelace GPUs and in particular the AD 102 (RTX 4090/4080 GPU).
Even with the bare board and lack of components, it’s possible to deduce what the PCB will contain in terms of components. Although these cards have been spotted they aren’t completely final so things may change. But even without so, it is likely to be a power-hungry and hot GPU. It will feature a great deal more power conversion especially if the total board power is the suggested 600 watts.
RTX 4090 and 4080 reference PCB features
From the reference board, it can be inferred that the PCB can handle up to 24 voltage converters. These VRMs convert the power from the power supply into a voltage the GPU can actually utilize. The jump in this generation is from the fact that the new 16 pin power connector can supply up to 650W of power in one cable. Even though it will still be at 12V there is still plenty more power for the VRMs to handle.
There is also a maximum of 12 solder slots for the GDDR6X memory (from Micron). As it currently is only available as 1 or 2GB modules it means it can have 12 or 24GB of memory. Likely to be in the same format as the 30 series with the 4090 having 24GB whilst the 4080 features 12GB. Whilst the lower-end cards are likely to feature 8 or 16 GB similarly to before. Which should also reduce the number of voltage converters on the less populated cards.
Is the RTX 3090 Ti a test run for the RTX 4000 series?
It is quite likely the delayed RTX 3090 Ti is a sort of prototype for the RTX 4090 GPU. Igor found out that the GA102 chip (3090/3080) is pin-compatible with the AD102 (4090/4080). This means that they will fit the same PCB and will likely be the same size. As well as giving board partners the ability to design for the new cards without actually having them. Although they will need an open 600W BIOS to properly test their cooling solutions. It also is meant to feature the new 16 pin power connector that will feature on the new graphics cards.
In terms of cooling solution, since it is such a hot chip it will likely increase the already bulky cooling solutions. Some sources suggest that Nvidia’s FE card will use a triple-slot cooler, with board partners going for a 3.5-slot design. Increasing the already large designs and making no space for other PCIe devices on your motherboard, and make all of them similar to the Noctua GPU. As well as likely increasing total weight of GPUs above the 2kg range, possibly leading for moe exploration into all-in-one water-cooling.
