The ASUS ROG STRIX RTX 3090 OC is a no-holds-barred implementation of the RTX 3090 with a huge triple-slot, triple-fan cooling solution. Unlike past generations, the bulk of the card's RGB bling has been moved towards the top-edge of the card as those parts of the card are more readily visible to you in a typical windowed case. When viewed from the front, you'll feel like the shroud is smothering the heatsink underneath. This is intentional as the three Axial-Tech fans direct all of their airflow axially, onto the heatsink. The shroud opens up along the sides and top, while the backplate has large vents that guide airflow from one of the fans straight through.
Dimensions of the card are 32 x 14 cm.
Installation requires three slots in your system.
Display connectivity options include three standard DisplayPort 1.4a and two HDMI 2.1. Interestingly, the USB-C port for VR headsets, which NVIDIA introduced on Turing Founders Editions, has been removed—guess it didn't take off as planned. The DisplayPort 1.4a outputs support Display Stream Compression (DSC) 1.2a, which lets you connect 4K displays at 120 Hz and 8K displays at 60 Hz. Ampere can drive two 8K displays at 60 Hz with just one cable per display.
Ampere is the first GPU to support HDMI 2.1, which increases bandwidth to 48 Gbps to support higher resolutions, like 4K144 and 8K30, with a single cable. With DSC, this goes up to 4K240 and 8K120. NVIDIA's new NVENC/NVDEC video engine is optimized to handle video tasks with minimal CPU load. The highlight here is added support for AV1 decode. Just like on Turing, you may also decode MPEG-2, VC1, VP8, VP9, H.264, and H.265 natively, at up to 8K@12-bit.
The encoder is identical to Turing. It supports H.264, H.265, and lossless at up to 8K@10-bit.
This BIOS switch lets you toggle between the default (Performance) BIOS and a "quiet" BIOS, which runs the fans much quieter, at slower speeds with higher temperature, and also reduces clocks slightly.
Two fan headers near the back of the card can be used to connect case fans to the graphics card. These fans will now run in sync with the graphics card fans—stopped when idle, at increasing speed depending on the GPU temperature. Since the graphics card is the primary heat source in most computers, this makes a lot of sense and helps keep noise levels down.
Unlike the NVIDIA Founders Edition card that introduces the new 12-pin power input, ASUS sticks to industry standard 8-pin PCIe power inputs, but there are three of them. Combined with PCIe slot power, this configuration is rated for 525 W. At reference specifications, the RTX 3090 is already shipping with 350 W typical board power, which maxes out power draw of two 8-pin connectors and begins to feed heavily on the PCIe slot. The third 8-pin input, which adds 150 W, is hence much needed for this card to have any meaningful power headroom.
The GeForce RTX 3090 supports SLI, and features a newer-generation NVLink bridge interface, which means you can't use your NVLink bridge from your Turing cards. Be warned that with Ampere NVIDIA isn't supporting SLI as in implicit multi-GPU (SLI as you know it), but explicit multi-GPU that's developed and supported by game/application developers. With multi-GPU game support being pretty much non-existent, this basically means SLI is dead. Perhaps creative and 3D modeling applications that support explicit multi-GPU can benefit from SLI.
Disassembling the ASUS ROG STRIX RTX 3090 OC is easy. The cooler comes out in one clean piece, leaving behind the PCB and a base plate. The latest-generation DirectCU III cooler features a vast aluminium fin-stack heatsink that covers the entire length of the card. Heat from the GPU is drawn by a "Max Contact" (mirror-finished nickel-plated copper) base and conveyed by seven heat pipes. The same Max Contact base also pulls heat from the memory chips on the obverse side of the PCB. The 2nd generation Axial-Tech fans offer all the benefits of guided axial airflow, but with lower noise.
The ROG STRIX RTX 3090 has a PCB that's shorter than the card itself, and so the base plate serves not just as a heat conveyor between some of the VRM MOSFETs and the cooler, but also a structural reinforcement.
With the RTX 3090 featuring memory chips on both sides of the PCB, the role of the backplate gains importance. ASUS is using a metal backplate with thermal pads over the memory chips as well as certain VRM components. The backplate has large holes punched through for airflow from the third fan to go through.