PSU for LTC/BTC miners / profitability

[qiuness]

Hi,

I just checked some charts on the net for cards at full load and i`m a bit stunned.
I mean i knew cards drew about 200-250w each but according to the stats below they draw much more:

Asus 6970 DirectCU2 - 340w
Even a 5850 draws - 283w
http://www.tweaktown.com/reviews/4207/asus_radeon_hd_6970_directcu_ii_video_card_review/index17.html

Are the charts wrong?

Now considering that you get 1000w PSU you can hardly fit 3 Cards on 1 Board. I`m not sure if buying 1200w PSU's to fit 4 Cards is viable.

I read that BTC mining takes less computing power (you can even downlclock the memory quite a bit with no impact to hashes).

Does that mean that BTC could be more profitable than LTC due to the reduced electricity cost?

What do you think?

[cimpex]

undervolt/clock and/or use a second PSU. 2 smaller one are often cheaper than 1 very strong (e.g. Enermax Platimax 1500W).
Take at least 80 Plus Gold to save power costs.
I don't think there is so much difference between BTC and LTC. Maybe if you can undervolt the memory.

[mitak64]

Hi,

I just checked some charts on the net for cards at full load and i`m a bit stunned.
I mean i knew cards drew about 200-250w each but according to the stats below they draw much more:

Asus 6970 DirectCU2 - 340w
Even a 5850 draws - 283w
http://www.tweaktown.com/reviews/4207/asus_radeon_hd_6970_directcu_ii_video_card_review/index17.html

Are the charts wrong?

Chart is correct, you are reading it wrong.

Read again: "Keep in mind; it tests the complete system ..."

[crazyates]

Ya I had a 5870, 5850, and 5830 pull ~650W at the wall back in the day. Now, my 7970 pulls about 340W at the wall, but both of those are for the whole system, not just the GPU. I'm also running the 7970 with a max OC, no undervolting, and I'm not underclocking my RAM as far as I could with MSI AB.

1000W for 3 GPUs or 1200W for 4 GPUs is going to be plenty, even with 7970s. If you're running 4x 6990 or 7990s, then you might have issues.