I'm currently using an RTX 4070 and recently rescued an RTX 3060 Ti from a discarded PC. It initially appeared dead because its cooler fans had failed and the card immediately overheated, but I repaired it and it now works. My motherboard is an ASRock B550M Steel Legend, and I could connect the 3060 Ti to the secondary PCIe slot with a riser cable if necessary. Could I have the RTX 4070 handle the game's main rendering while the 3060 Ti handles DLSS, upscaling, frame generation, or another graphics feature?
3 Answers
The second PCIe slot on that motherboard is electrically slower than the primary slot, and a riser can introduce compatibility or signal-quality problems. It may be useful for compute, rendering, or AI workloads, but adding the 3060 Ti will not improve gaming performance when the 4070 is already doing the rendering.
You can physically install both cards, assuming the power supply, slot spacing, and riser cable are suitable. However, modern games generally cannot split the workload that way. The GPU rendering the game normally handles its own DLSS and related features, so the 3060 Ti would not simply take over DLSS processing for the 4070. Multi-GPU gaming support is rare now and usually has to be implemented specifically by the game or through specialized software.
For gaming, you would generally get more practical value by selling one or both cards and putting the money toward a stronger single GPU. A single card has much broader game and driver support than trying to make two different GPUs cooperate.
There are some niche setups where a second GPU can assist with a particular effect or workload, but that is not a standard feature and is unlikely to work reliably across normal games.