GPU confusion

Ok so,

I have a very limited knowledge of the workings of a computer. Been a gamer now for about 7-8 years so have the basic stuff down but not much else.

I have about a 3 year old pc, I was trying to ride it out until holiday newegg sales and build a new one. I recently purchased Final Fantasy 14 which has been a HUGE strain on my PC. At its lowest settings it ran it very very slow but just enough. Today I was playing and graphics started tearing all over the screen until my computer froze. Restart, rinse repeat same outcome. It can handle Team Fortress 2 though for some odd reason. According to MSI Afterburner my GPU is getting no Core Voltage from the power supply, but the fan is running and when I slide the fan control up and down it responds. Also sometimes the fan will just stop working, but on a restart it will begin working again. I run a 9800gt which typically runs hot I know, and to compensate until the holidays and my xmas present to myself I had opened my case and placed an outside fan blowing in to cool it off.

I'm sure this is just a wall of noob to some of you, but I truly appreciate any help.

Bryan

 

Fans run on 12V but the power supply must also provide 5V and 3.3V. It sounds like your PSU is failing. Here's my canned text on testing PSUs:

To properly and conclusively test a power supply unit (PSU), it must be tested under various realistic "loads" then analyzed for excessive ripple and other anomalies. This is done by a qualified technician using an oscilloscope or power analyzer - sophisticated (and expensive) electronic test equipment requiring special training to operate, and a basic knowledge of electronics theory to understand the results. Therefore, conclusively testing a power supply is done in properly equipped electronic repair facilities.

Fortunately, there are other options that are almost as good. I keep a FrozenCPU Ultimate PSU Tester in my tool bag when I am "in the field" and don't have a good spare power supply to swap in. While not a certain test, they are better than nothing. The advantage of this model is that it has an LCD readout of the voltage. With an actual voltage readout, you have a better chance of detecting a "failing" PSU, or one barely within specified ATX Form Factor Standard tolerances. Lesser models use LEDs to indicate the voltage is just within some "range". These are less informative, considerably cheaper, but still useful for detecting PSUs that have already "failed". Newegg has several testers to choose from. All these testers contain a "dummy load" to fool the PSU into thinking it is connected to a motherboard, and therefore allows the PSU to power on, if able, without being attached to a motherboard - great for testing fans, but again, it is not a true load or suitable for conclusive testing.

Note the required voltage tolerance ranges:

NOTE: Disregard the -5VDC reading. It is no longer used.​

Swapping in a known good supply is a tried and true method of troubleshooting used for years, even by pros. If you have access to a suitably sized, spare power supply, carefully remove the suspect supply and replace it with the known good one, and see if the problem goes away.

I do not recommend using a multimeter to test power supplies. To do it properly, that is, under a realistic load, the voltages on all the pins must be measured while the PSU is attached to the motherboard and the computer powered on. This requires poking (with some considerable force) two hard and sharp, highly conductive meter probes into the main power connector, deep in the heart of the computer. One tiny slip can destroy the motherboard, and everything plugged into it. It is not worth the risk considering most multimeters, like plug-in testers, do not measure, or reveal any unwanted and potentially disruptive AC components to the DC voltages.

And remember, anything that plugs into the wall can kill. Do not open the power supply's case unless you are a qualified electronics technician. There are NO user serviceable parts inside a power supply. ​