Hello, I changed my CPU from an Intel i3 4160 (2 cores 3.6 GHZ, LGA 1150) to an i5 4570S (4 cores 2.9 GHZ, LGA 1150) hoping to improve the gaming graphics. Now the onboard INTEL 4400 graphics is missing, vanished, gone. The graphics driver is now a Microsoft generic, The board is an ECS H81H3 M4 Haswell mini ATA with 16 GBytes ddr3 memory. The BIOS reports that the CPU is missing the hyperthreading function. That is unrelated to the problem, right? Can anyone help me get my onboard graphics back?
That is an APU and not a CPU, so the GPU is on the same Processor package, so your Graphic Driver needs to be upgraded to a Intel HD 4600 from HD 4400 drivers. Specs are in inks below that show the GPU difference in those APU's. So the driver for the Intel HD 4600 needs to be installed as the fix to this. Regarding the Hyperthreading... I have HEARD of ECS boards reporting wrong about Hyperthreading. I would check the processor when RUNNING Windows to see if the Hyperthreading virtual cores are missing or not. ECS is not a quality product and is a quantity for cheap board. NOTHING good to say about that brand.

https://ark.intel.com/products/77488/Intel-Core-i3-4160-Processor-3M-Cache-3-60-GHz-

https://ark.intel.com/products/75044/Intel-Core-i5-4570S-Processor-6M-Cache-up-to-3-60-GHz-The i5 4570S doesn't have hyper-threading, as listed on the ARK page.