In simple terms can someone explain something to me?

[mxc0bbn]

What is the relationship between voltage and clock/mem speeds?

I've read so much about how undervolting is great for power consumption and equipment longevity, but I'm wondering if that's just for BTC.  Since I'm doing LTC I need a higher mem clock.  Everything I've read about undervolting lowers mem clock.  Is this right?  If not someone please explain it to me like I'm 10.

[nwoolls]

Voltage affects the stability of the card at its given core and memory clocks. It also affects the temperature of the card and power consumption. If you are overclocking, you may need to increase the voltage to keep things stable. If you are looking to save power and reduce heat, undervolting will help but you have to keep your clocks in check so things are stable.

[EngMan]

For my LTC rigs, I try to find the best kh for the card...then maybe try a slight undervolt in small steps to see if you can keep the card stable while keeping the performance. Every card is different though. GPU-Z can help see how good your card is.

[ScaryHash]

If you jack up the clock speed of the gpu, you have to usually give it more voltage to keep it from freezing up. More voltage = more power = more heat.

If you jack up the memory speed, you have to usually give it more voltage as well, to keep the memory firing. More voltage = more power = more heat.

If you UNDERCLOCK the memory, but jack up the GPU speed, you can usually get away with undervolting, so it will use less power.

How much that is, you have to play with it.

As an example, I have my 7950 overclocked to 1075 mHz (from 925), underclocked memory to 950 (from 1200 I think), and undervolted at 1150 mV  (from 1250 mV).

This allows the card to run at 67 C, instead of 74 C, than if I had it at 1000 mHz, full memory clock, and full voltage of 1250 mV.

Basically, turn down the memory and voltage, jack up the GPU, and you can manage your temps better also. I get about 520 mHashes with my settings, versus 460 at stock....so, that's a gain.

It is worth it to note that on this card, Powercolor 7950, the memory does not have heat sinks on it, and the cooler generally sux...but anyway.

I'm sure other people will have other things to add, but those are my findings (so far).

[Malawi]

What is the relationship between voltage and clock/mem speeds?

I've read so much about how undervolting is great for power consumption and equipment longevity, but I'm wondering if that's just for BTC.  Since I'm doing LTC I need a higher mem clock.  Everything I've read about undervolting lowers mem clock.  Is this right?  If not someone please explain it to me like I'm 10.

BTC mining does not use the memory, so you want the memory to consume as little electricity as possible. This lowers the heat on the card so that the GPU can run a little faster without overheating.

LTC mining DOES use the memory, so you want to balance the GPU and memory vs heat/power.