stratosfearical :
I have got an q77 express motherboard with an i7-3770, and I am upgrading to a higher form atx to make space for a gtx 970. Can someone list me the cheapest PSU I can purchase that will be compatible. The q77 chipset I have doesn't seem to be compatible with any of the models I have found. I am pretty sure that the gtx 970 can connect to my motherboard, but just needs a supporting power supply. I am looking to spend under £40 for the PSU , and I live in the UK.
The Q77 chipset is an Intel chipset that usually is found on business computers (from OEMs like Dell, HP, etc.) that may or may not have a full x16 GPU slot. They usually have smaller, often custom-designed PSUs from makers like Delta. They can run smaller in output (sometimes less than 200W) because they were only meant to power the CPU + motherboard, a HDD, and sometimes an optical drive.
So if you have a full x16 PCIe slot, then the next step is to confirm your PSU has enough output to run everything you have in your system. I would guess you will need at least 350 - 400W; that should be just enough to run the system with the 970. If it's loaded up with other devices like 2-4 extra HDDs, etc., then you may need more. So if you need a larger one, your issue might be to find a PSU that fits your case.