Just got a 780ti and can't seem to get a stable overclock. I can get +50 on the core on stock volts and no higher. But as soon as I touch the voltage I get artefacts not matter how much I raise. Even keeping it at +50 and raising volts from stock I artefact. Is it sounding like RMA time?
EVGA 780Ti classy won't OC
- Thread starter Snookums
- Start date
Not sure you would be able to RMA on it on the basis that it won't overclock? But I guess it wouldn't hurt to ask. What are the temps like, I think on the Classifieds you have VRM temp sensors? What PSU are you using? What speeds is it actually running at, if you got it used then maybe the previous owner flashed the BIOS with higher clocks?
I admit to being out of my comfort zone with PSU's but yours could be the issue, it's 12v rail is split into 4 (22A/22A/25A/25A) the 780Ti needs 42 Amps on a single rail. I think possibly Your PSU is struggling to deliver sufficient power to the card hence why as soon as you start putting extra demands on it through overclocking or upping the voltage you get issues. It's the avenue I would explore and get some more opinions on as even if you do get a replacement card you may end up with the same issues.
Remember the card is factory overclocked, +50 on the core is actually +195 on the core.
If you check out the link to the MSI power requirements page I gave you the 7950 only needs 25A on a single rail which your PSU would have been capable of.
If he uses one PCI-E cable from each rail (2 in total) it should be able to provide sufficient power draw I believe.
The more I try to understand the way this works the more my head hurts
From Here
Rail 1 - (solid yellow wire) Main motherboard cable, peripheral power plugs and SATA power plugs.
Rail 2 - (yellow with black stripe wire) ATX12V & EPS12V
Rail 3 - (yellow with blue stripe wire) one video card connector from inside the PSU & one from the modular cabling.
Rail 4 - (yellow with green stripe wire) same as Rail 3
So theoretically as long as you are using the 2 VGA power leads that come from inside the PSU you will be using the 2 25A rails (3&4) also some power will be coming through the PCIE slot, so this should be sufficient for the 42A required. If you're using one of the VGA connectors from inside the PSU with a modular lead that happens to be coming from the same 25A rail then this might explain the problem.
Well there's 2 trains of thought, one train says none of your 4 single rails can provide the 42A that is stated as a requirement - "42A on a single rail". The other train says you do have a single physical 12v rail that is split into 4 and you should be able to get the 42A you need from the connections you are using. I was initially on the first train but after reading up a bit more am pretty much on board the second one but I would maybe post a new thread in the PSU section to see if you can get any more input. Also if you're logging a case with EVGA let them know what PSU you have and they'll soon tell you if they think it's not good enough.
Already got in contact with evga (very slow replies) they said nothing about the psu just that apparently I can't expect any more of an overclock than what's stock. Still not answering my worry of why more volts creates artefacts. Thanks for all the help though. Hopefully I can RMA the card. Want to be able to squeeze a little extra juice out of this.