It's not irrelevant, it's just not a real figure as those measured at the wall.

I've mined with 270x, 7950, 7850, 7970, and I know what I'm talking about!

Old cards are very inefficient. That's a fact!

Besides being noisy and generating a lot of heat.

GPU-Z readings are a good way to compare efficiency between different cards, or different setting for the same card.

Therefore, they're not irrelevant. In fact, they are very useful  

gpu-z only shows draw from pcie, which I think for newer cards is mostly memory related

Even so, If I'm getting 35 sols drawing 40w and someone else is getting 50 sols drawing 100w how can that be irrelevant?

You do the math  

PS: I pay for my electric bill!

Even so, If I'm getting 35 sols drawing 40w and someone else is getting 50 sols drawing 100w how can that be irrelevant?

You do the math  

PS: I pay for my electric bill!

But you are not getting 35 s/s from 40w, get a killawatt and you will see your card pull atleast double that from the wall.
Sure, you pay your own electric bill but dont fool people with completely wrong numbers.

It's not completely irrelevant. But you absolutely CANNOT accurately use GPUz power draw to compare different cards because they all have different power characteristics. It's only good for doing apples to apples comparisons.

For example, mining Ethereum, I have RX480s that say 70~75w in  GPUz but this relates to more like 120w from the wall. So a 50w difference.

But my 290x, say around 130w in GPUz, but 200w from the wall, that's a 70w difference.

Basically, you have almost no way of telling actual power draw from the wall with GPUz, it's just a guessing game. And power draw from the wall is what actually counts.

And why do you need 2 x 850w PSU to power 6 x RX480? Even mining Ethereum at 180mh/s my 6 x RX480 only pull 810w, from the wall. You certainly don't need it for ZCash, I'm not even pulling 600w from the wall.

20 4E 00 01 33 31 33 20 00 00 00 00 61 88 11 08 D0 54 07 04 0C 07 C1 00 00 21 60 00 22 AA 1C 00 02 00 14 20 8A 88 80 A1 00 00 01 20 03 02 06 07 09 08 0D 0B
40 9C 00 01 55 51 33 20 00 00 00 00 63 10 22 10 10 55 09 09 10 0E 92 01 00 21 60 00 22 AA 1C 00 2B 01 14 20 8A 88 00 A3 00 00 01 20 05 04 0C 0D 11 0F 11 0E
80 38 01 01 55 51 33 20 00 00 00 00 E7 A4 44 20 50 55 0B 0D 1A 97 34 03 00 26 A1 00 22 AA 1C 00 4B 06 14 20 9A 88 C0 A5 00 00 01 20 0A 08 17 19 21 18 1B 11
90 5F 01 01 55 51 33 20 00 00 00 00 08 29 45 24 50 55 0C 0D 1C 18 A5 03 00 27 C1 00 22 AA 1C 00 4B 07 14 20 9A 88 80 A6 00 00 01 20 0B 09 1A 1C 25 19 1D 11
A0 86 01 01 55 51 33 20 00 00 00 00 29 AD 55 27 50 55 0C 0D 1E 99 05 04 00 28 C2 00 22 AA 1C 00 4B 08 14 20 AA 88 00 A7 00 00 01 20 0C 0A 1C 1E 28 1A 1F 11
74 B7 01 01 55 51 33 20 00 00 00 00 6B B5 66 2D 60 55 0D 0E 22 9C 96 04 00 29 E3 00 22 CC 1C 00 53 0A 14 20 BA 88 00 A8 00 00 01 20 0E 0C 20 22 2E 1D 23 12
48 E8 01 01 55 51 33 20 00 00 00 00 8C 39 67 31 70 55 0E 0F 24 1E 17 05 00 4B 04 01 22 DD 1C 00 5B 0B 14 20 4A 89 C0 A8 00 00 01 20 0F 0D 23 25 32 1F 25 13
1C 19 02 01 55 51 33 20 00 00 00 00 AD 41 78 37 80 55 0E 10 28 21 98 05 00 4C 05 01 22 FF 1C 00 63 0D 14 20 5A 89 C0 A9 00 00 01 20 11 0E 27 2A 38 22 29 14
F0 49 02 01 77 71 33 20 00 00 00 00 CE C5 88 3B 80 55 10 11 2B A3 18 06 00 4E 26 01 22 11 9D 00 6C 0E 14 20 6A 89 80 AA 00 00 01 20 12 0F 2A 2D 3C 24 2C 15

20 4E 00 01 33 31 33 20 00 00 00 00 61 88 11 08 D0 54 07 04 0C 07 C1 00 00 21 60 00 22 AA 1C 00 02 00 14 20 8A 88 80 A1 00 00 01 20 03 02 06 07 09 08 0D 0B
40 9C 00 01 33 31 33 20 00 00 00 00 84 94 22 10 F0 54 09 06 0F 0B A2 01 00 23 80 00 22 AA 1C 00 12 01 14 20 8A 88 00 A0 00 00 01 20 06 05 0B 0C 11 0C 10 0D
80 38 01 01 55 51 33 20 00 00 00 00 E7 AC 35 20 50 55 0B 0D 1A 97 34 03 00 24 81 00 22 AA 1C 00 4B 06 14 20 9A 88 00 A0 00 00 01 20 0C 08 15 19 21 18 1B 11
A0 86 01 01 55 51 33 20 00 00 00 00 29 31 46 24 50 55 0C 0D 1C 18 A5 03 00 26 A1 00 22 AA 1C 00 4B 07 14 20 9A 88 00 A0 00 00 01 20 0D 0A 18 1B 25 19 1D 11
1C 19 02 01 55 51 33 20 00 00 00 00 29 B5 46 27 50 55 0C 0D 1E 99 05 04 00 26 A2 00 22 AA 1C 00 4B 08 14 20 AA 88 00 A0 00 00 01 20 0E 0A 1A 1E 28 1A 1F 11
78 5D 02 01 55 51 33 20 00 00 00 00 6B BD 57 2D 60 55 0D 0E 22 9C 96 04 00 28 C3 00 22 BB 1C 00 53 0A 14 20 BA 88 00 A0 00 00 01 20 10 0C 1E 22 2E 1D 23 12
10 98 02 01 77 71 33 20 00 00 00 00 8C C5 48 2F 60 55 0F 0F 25 1E 17 05 00 48 C4 00 22 CC 1C 00 5C 0B 14 20 4A 89 00 A0 00 00 01 20 12 0D 20 25 32 1F 26 13
30 E6 02 01 77 71 33 20 00 00 00 00 AD CD 49 2F 70 55 0F 10 29 21 98 05 00 4A E5 00 22 EE 1C 00 64 0D 14 20 5A 89 00 A0 00 00 01 20 14 0E 24 2A 38 22 2A 14
40 0D 03 01 77 71 33 20 00 00 00 00 CE 51 4A 2F 70 55 10 10 2B A2 18 06 00 4A E6 00 22 00 9D 00 64 0E 14 20 6A 89 00 A0 00 00 01 20 15 0F 27 2D 3C 23 2C 14

Not necessarily, but I'd have thought 470 should pull a little less. It all depends on the voltage you supply the GPU.