I currently have a system with an Intel CPU and an integrated GPU (see below). I am pondering adding a more powerful GPU, say, along the lines of these:
https://www.newegg.com/gigabyte-geforce-gtx-1070-gv-n1070ixoc-8gd/p/N82E16814125893 https://www.newegg.com/gigabyte-geforce-gtx-1060-gv-n1060ixoc-6gd/p/N82E16814125903?&quicklink=true
The specs of my system are as follows:
Motherboard: https://www.newegg.com/p/N82E16813157504?Item=N82E16813157504
Memory (x2): https://www.newegg.com/corsair-8gb-240-pin-ddr3-sdram/p/N82E16820233366?Item=N82E16820233366
Power Supply: https://www.newegg.com/silverstone-sfx-st30sf-300w/p/N82E16817256097?Item=N82E16817256097
CPU + GPU: https://www.newegg.com/intel-core-i7-4th-gen-core-i7-4790k/p/N82E16819117369?Item=N82E16819117369
CPU Cooler: https://www.newegg.com/noctua-nh-u9b-se2/p/N82E16835608016?Item=N82E16835608016
HDD1: https://www.newegg.com/seagate-1tb-st1000lm014/p/N82E16822178340?Item=N82E16822178340
HDD2: https://www.newegg.com/seagate-barracuda-4tb-st4000lm024/p/N82E16822179105?Item=9SIAAY9AWM5481
My question is whether adding the new graphics card will prove too much for the 300W power supply. The estimate I have made was 88W for the CPU, based on the so-called Thermal Design Power or the amount of heat the sink needs to dissipate. I also know that the new card will require about 120-180W of power, depending on the model. This leaves us with about 100 Watts for everything else in the machine.
Basically, the question is whether I should be able to make this work without swapping the power supply. I really like the latter and am not sure whether the company still makes something similar.
How can I estimate the power consumption of the rest of PC?
How much "allowance" and "breathing room" should one have in form of the wattage not taken up by anything to make the system stable and not shut down suddenly because of lack of power?