Leaked Nvidia RTX 4000-series PCB design confirms 600 W TGP, reveals VRAM configurations, power delivery scheme, and cooling solutions
Up until now Nvidia confirmed through the Hopper announcement that the high-end RTX 4000 GPUs launching in the second half of 2022 will feature a monolithic design that can still be cooled with air-based solutions, plus the TGP for the top-of-the-line models should not be over 700 W. Moore’s Law Is Dead suggested that the TGPs could max out at 600 W, with 450 W typical. More elaborate proof in this regard was recently provided by Igor Wallossek from Igor’s LAB, who managed to obtain schematics for the RTX 4090 / 4080 PCB boards revealing details on memory configuration, pin layout, voltage supply and cooling solution.
Before getting into the details, Igor reiterates his belief that the upcoming RTX 3090 Ti cards are some sort of test product for the RTX 4000-series. This is because the RTX 3090 Ti (full GA102 SKU) will be the first card to feature the PCIe 5.0 power connector, which can easily support TGPs of 450 to 600 W.
The first detail about the RTX 4000 PCBs revealed by Igor is the pin-compatibility between the GA102 board design and an alleged AD102 (Ada Lovelace) reference design. This is particularly beneficial for Nvidia’s AIB partners, since they could reuse the custom RTX 3090 Ti designs for the RTX 4080 / 4090 cards and therefore save substantial development costs in the process.
Power delivery on the AD102 PCB consists of 24 voltage converters for the VRMs and 4 for the VRAM, which ups the total phases from 20 on the RTX 3090 designs to 28. Igor’s sources claim that this particular AD102 PCB is used with a modified GA102 600 W BIOS for internal testing, as the Ada Lovelace RTX 4000 chips have not yet been delivered to board partners.
Furthermore, the rumored 600 W TGP appears to be confirmed by Igor when he mentions that AIB partners are required to bundle a 4x8-pin to 12VPWR (12+4) adapter with each card. For reference, the 450 W RTX 3090 Ti includes a 3x8-pin adapter. As far as VRAM is concerned, the AD102 PCB features 12 soldered GDDR6X chips, indicating that the total amount could go up to 24 GB. Versions with 8, 12 and 16 GB are also possible, although 8 is already quite low for a mid-range card these days.
Lastly, Igor touches upon the cooling system, citing sources that claim the reference or FE designs will rely on triple-slot solutions, while custom designs from AIB partners could use 3.5-slot solutions. Nvidia is also considering factory-grade AIO compact coolers and water blocks, but not as primary solutions.