Optimus Graphic card identification

Question

With this data, Graphic card is Optimus?

~$ lspci -nn | egrep -i "3d|display|vga"
00:16.3 Serial controller [0700]: Intel Corporation 6 Series/C200 Series Chipset Family KT Controller [8086:1c3d] (rev 04)
01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GK208 [GeForce GT 720] [10de:1288] (rev a1)

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If this is Optimus, which one is better?

Using PRIME Render Offload - Theoretically, with Debian 11 (or newer), special configuration shouldn't be needed and offloading should be available as soon as you've installed the proprietary drivers. See the relevant section for more details.

Using only the integrated GPU - Uses little battery power but is also low performance, as the NVIDIA GPU will be completely powered off. Still, this is suitable for some use-cases.

Using only the NVIDIA GPU - High performance but is also a massive drain on battery life. There's almost always a better solution than this, but it's useful if you expect to use your laptop as a desktop (i.e. always plugged in).

Using Bumblebee/Primus - An alternative solution to PRIME Render Offload that works similarly, with support for both Nouveau and the proprietary drivers. Up to Debian 11, this has had severe performance issues for some. While the situation is much better in Debian 11, this should really only be used if the official PRIME Render Offload functionality in the proprietary drivers does not work for you.

Using nvidia-xrun - Runs a completely separate desktop session with the NVIDIA card, achieving maximum performance from the GPU at the cost of extra complexity.

Using Nouveau - Nouveau is the open-source driver for NVIDIA GPUs. It also supports PRIME Render Offload via Mesa without the need to use the proprietary drivers. Unfortunately, it does not support Vulkan and has severe performance issues, particularly with modern cards.

Answer 1

00:16.3 Serial controller [0700]: Intel Corporation 6 Series/C200 Series Chipset Family KT Controller [8086:1c3d] (rev 04)

This is not a display controller at all. Your grep is catching the "3d" part in the vendor:product ID (8086:1c3d).

This looks like it would be the part of the Management Engine that acts as a virtual serial port that would be accessible over the network if the Management Engine is configured, so according to pages 51-53 of the datasheet, this chipset would be either Q67, QM67, QS67 or C206. But all those would support the iGPU also, so it looks like you may have a CPU model that does not include the iGPU, or perhaps the iGPU has been disabled in BIOS and hidden from the OS.