DDR3 undervolt Karbylake


May 17, 2017
I plan on building a low budget PC. I want to use G4560 (Kaby Lake) with 2x2 GB DDR3 for active dual channel mode, so I can get better performance for IGP 610. A friend told me that DDR3 will automatically undervolt to 1.42V for his G3900 (Sky Lake). He said it's safer.

Is it safe for Kaby Lake to use that setup for 12 hours a day? Or will it damage my processor or motherboard?


I wouldn't do it personally, also I'm not aware of a b250 ddr3 board, so you'd need a skylake CPU to update the BIOS on a h110 board possibly. Be a lot easier to just get 2400mhz dual channel ddr4 kit and actually improve the onboard graphics. Hd610 stinks adding slow ddr3 will make it much worse. I'd get a 4600 instead of a 4560 if I was going to actually use the on board video
I just tried a PCPartpicker sort for 200 series motherboards (B250, Z270, H270) with DDR3 support... there are exactly zero. As @Supahos says, you could get a H110 or B150 board and get a BIOS update, perhaps a local store might help you, or some could perhaps even update the BIOS for you prior to purchase, but then you're still running 1.5V RAM in a 1.2V (OC to 1.35V) memory controller. It's really not a good plan.

You can get a single 4GB DDR4 2400mhz DIMM for $27: https://pcpartpicker.com/product/GXbkcf/patriot-memory-psd44g240081
That'll go in a B250 board and run at 2400mhz. Adding a DIMM second later would probably give you dual channel 8GB which is fine for entry level gaming. Buying unmatched kits does pose small risk that dual channel won't work, but usually you're fine at standard frequency and timings (which 2400mhz RAM is).

Are you wanting to game on this machine with the iGPU? That's a tight budget.