pushing past 90% on a Bronze rated 80+ PSU

[glendall]

My 700W Corsair is coming along nicely with my 2 x 7950 rig now that I've had time to work on the system.

The reason why it was crashing out before was because I *very* dumbly knocked one of the cards one of the last time I was fiddling with my fans. Some of the pegs/teeth were hardly half engaged -- surprised it even ran at for 20 mins and even more surprised I didn't burn out any parts with that dumb move of mine.

Reading this thread and some other articles recently on PSU's think I have new respect/understanding for Gold rated PSUs. Does seem like its a better choice in Wattage savings and reliability to go for the more expensive PSUs when they are going to be running 24/7 @ top Wattages like most miners are.

[cdog]

I dont know, but Im running 2x6950s on a 500w supply, I figured Im close to capacity but it should hold

[DrG]

I dont know, but Im running 2x6950s on a 500w supply, I figured Im close to capacity but it should hold

At home I have 2 MSI 7950s running on an Antec HCG-400 (400 Watt PSU) inside my main rig inside a case.  I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

Remember as PSUs age their output capacity will decrease.  Efficiency will stay more or less the same but the midrange and crappy 600W PSUs will only be able to put out 500W on the 12V after a couple of years.  I think GOLD/Plat PSUs would be better at handling this degradation.

[Starlightbreaker]

I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

wtf.

[datguyian]

Curious, anyone ever use top power for mining with 3+ GPUs? they have a 1000W gold certified on new egg for $99.99.... never heard of the brand, so I'm not exactly jumping on it. I also saw a decent coolmax 1200W 80+ gold for $160, but haven't heard of them either. Seeing as how I'm working on my first and only mining rig, I don't want to take a chance on an offbrand PSU that will end up crapping out on me within weeks.

I'm thinking of going with this one for my first rig, starting with two 7950's:

XFX P1-850B-BEFX 850W ATX12V 2.2 & ESP12V 2.91 SLI Ready CrossFire Ready 80 PLUS GOLD Certified Full Modular Active PFC Power Supply  -  http://www.newegg.com/Product/Product.aspx?Item=N82E16817207028

I'm hoping I'll be able to get a third GPU on it in the next month without having to upgrade or get an additional PSU. Any thoughts or experience with this particular PSU w/3 or more GPUs?

[crazyates]

I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

wtf.

That makes perfect sense. Why are you so confused?

My 7970 undervolted to 950mV, 900MHz core, and 375MHz mem gets me 520MH/s, while only pulling 108W (Just the card, not total system). Temps are also crazy low, like 30-40C @ 40% fan (silent). 2 of these, and it's quote easy to obtain.

[DrG]

I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

wtf.

That makes perfect sense. Why are you so confused?

My 7970 undervolted to 950mV, 900MHz core, and 375MHz mem gets me 520MH/s, while only pulling 108W (Just the card, not total system). Temps are also crazy low, like 30-40C @ 40% fan (silent). 2 of these, and it's quote easy to obtain.

Well I could get even lower wattage if:
1) My main rig didn't also power 2 HDs in addition to the SSD boot drive
2) I ran an econo CPU instead of an I5-2500K
3) I actually spaced the cards with risers - as it stand they're separated by 0.5 inches so they both run warm/hot 70-80C

The cooler the cards are the less power they'll suck.  It's kind of a vicious cycle.  But it's my main computer and I never mine at home except now with the crazy BTC prices.  Once my Avalons and unicorn blood coated BFL Singles arrive I'll toss all but 2 cards haha.

My power costs me $0.40 since I got kicked up to Tier 5 just by mining on those 2 7950s even with the undervolt.  Don't move to SoCal if you want to mine with GPUs.

[crazyates]

I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

wtf.

That makes perfect sense. Why are you so confused?

My 7970 undervolted to 950mV, 900MHz core, and 375MHz mem gets me 520MH/s, while only pulling 108W (Just the card, not total system). Temps are also crazy low, like 30-40C @ 40% fan (silent). 2 of these, and it's quote easy to obtain.

Well I could get even lower wattage if:
1) My main rig didn't also power 2 HDs in addition to the SSD boot drive
2) I ran an econo CPU instead of an I5-2500K
3) I actually spaced the cards with risers - as it stand they're separated by 0.5 inches so they both run warm/hot 70-80C

Ya I got 1HDD, 1 SSD, and an AMD 8-core 8120. I feel ya.

[Starlightbreaker]

I had to undervolt the cards but am able to pull 1050MH/s on 375W at the wall.

wtf.

That makes perfect sense. Why are you so confused?

My 7970 undervolted to 950mV, 900MHz core, and 375MHz mem gets me 520MH/s, while only pulling 108W (Just the card, not total system). Temps are also crazy low, like 30-40C @ 40% fan (silent). 2 of these, and it's quote easy to obtain.

not confused, only amazed how efficient the latest generation gpus are.

sigh.

back to the mining game again.

[witherworth]

Ive got a 750w bronze rated PSU that runs 4 seriously overclocked 5850s (150w each without overclock). Only recently have I had an issue where I had to physically unplug the PSU and wait a few seconds before it would let me turn it back on (overdraw protection I believe). It's been doin pretty fine otherwise, and in the 1.5 years I've had it, only had this issue happen twice. I think I've definitely gotten my monies worth.


But otherwise, don't cheap out on power supply.