GPU Overclock Voltage Increase makes no difference?

[PantThrower]

Firstly, apologies if I'm posting this is in the wrong place and it should be in the "Overclocking section". This is my first venture into overclocking and first time posting on this site.

I'm trying to overclock my Zotac 980ti Amp Omega. Following several guides I have gradually stepped the core clock up by +120MHz and Memory Clock by +225MHZ without any increasing in voltages. At these settings it's rock solid.

If I try to go any higher on the core or memory the system becomes unstable. All the guides say that it at this stage that I should start to increase the voltages. I've used MSI Afterburner and bumped voltages, power limits and temp limits up but it doesn't make any difference. The system still becomes unstable even at Core Voltage +87mV, Power Limit 110% and Temp Limit 87 deg.

I've also noticed that when I stress test in Kombustor the GPU never goes above 68 degree, regardless of me maxing out the setting and letting it run for an hour.

Am I missing something/doing something wrong or have I just reached the limit of the card?

Ray

 

[Vellinious]

Open up GPUz to the sensors tab, and see if adding voltage actually adds voltage. Quite a few of the Maxwell cards are locked at 1.212v, and won't go any higher regardless of the settings in the overclocking software. Or, you could just have a card that doesn't like additional voltage. The GM200s seems to suffer from that more than the GM204s.

Also, when you're overclocking, you should always have the power target slider maxed out. Maxwell cards all have artificially low power limits set in the stock bios files, and in order to keep from hitting the power limit perf cap too soon, the power target slider should be at it's highest position.