You could go the route I'm taking and add a cheap secondary PSU.  I'm adding a Corsair AX430 to each of my rigs to power a couple 5830s.

I think the current driver is limited to 8 cards.

Indeed it would, the molex power adapter allows the card to pull that 75W directly from the PSU, instead of through the motherboard.

You only really need the 1x adapter with molex however, mining is not bandwidth intensive so you don't need all the lanes available to 8x or 16x

Nah probably not, you better just send them all to me. 

O.o

800W for a single 6990 system?  What the hell have you got, a cuisinard? /spaceballs

Seriously though what do you have in there?  A single 6990 has a TDP ~400W - you should be able to run two in a 1KW envelope.

That's the 6950 with it's 1408 shaders,  flashable to be a 6970 with 1536 shaders.

Except it's a huge gamble whether or not the shaders will be unlockable or function, even on a reference board.  I have 4 XFX 1GB 6950's and not a single one opened up locked shaders for me.

Don't go for the 6950 counting on making it a 6970, the odds are well against you.

For the love of god, it's waste!

Waist is your midsection.  Where all the beer goes.

These two rogue cards are in the same machine?  If so, might not be the cards.. tried swapping them into another rig?

Way to pay attention to the details, you're totally right!

The V2 is fully 80+ certified, at ~300W it's 84.6% efficient with 0.99PF.  Amazing!

Efficiency seems to jump a percent or so when only loading the 12V rail, I expect I'd cross 85% just powering GPUs.

Considering I can get two of these for the price of that FSP addon supply, I think you found me my answer.

$50 / board for 50MH would be a pretty great starting price for FPGAs considering the power savings.  It might only be a 1/1 ratio, but if each chip used, say, 10W you can do 1GH/s for ~200W - I'd save nearly $450/yr/rig over what i've got

Thanks

I looked over the review at Jonnyguru, it turns out that these PSUs were 'full of misinformation in the product specs', according to Corsair.  The big one there being that these are not actually 80+ certified!

That said, Jonny's review showed peak efficiency at 83%, and with only the 12V rail loaded the power-factor was 0.99!

They seem like a great option, I'll definitely keep them in mind.  Wish they were modular and 85%+ at peak, but that's asking quite a lot for a cheap <600W PSU

Like that it's Active PFC.

Dislike that it's 75% efficiency.. blech.  My 'random PSUs lying around' can do this already.

Supplement to this since I forgot to mention it - I'd rather not have a larger (750W+) PSU straddled between the two systems, though that would keep me on budget.  I don't particularly like the idea of 'crossing streams', or having to take down extra GPUs if I need to move a system.

Hey guys, I'm looking for a recommendation on an itty bitty power issue I've run up against.

Here's the deal, I've got two systems, in each:

• 2 x XFX 1GB 6950 (~200W each, 885 / 760 gpu/mem clocks)
• Sempron 140 (45W), undervolted and clocked down to 800mhz
• 1GB DDR3-1333, undervolted and clocked down to 400mhz
• 1x  Corsair HX750W 80+ PSU

At the socket, these guys each drew 435W max.

I picked up a few 5830's the last time they were in stock on newegg, and I'm adding 2 to each system.

I setup the first rig last night in it's new extender-equipped open air frame (yay!), everything working great, except I'm now drawing ~755W at the socket.

I know my Corsair can handle it just fine for a while, but obviously there's efficiency loss, the PSU got pretty warm, and I worry about long-term stability.  It seems I now need to supplement my power on these rigs to keep it all happy-good-times.


I figure I've got 3 options here:

1) Go big with an AX1200 in each rig... this is way outside my short-term budget

2) Throw in whatever PSUs I've got lying around to power the new 5830's - this is OK short-term but I leave a lot of efficiency on the table

3) Pick up a reasonably priced, 80+ supplementary PSU


This is where I'm stuck at the moment - #3 is likely my best option, but I've got little experience with smaller 80+ PSUs, I've never really had much concern for efficiency until now.  I'd love to pick up more of these Corsair HX750 PSUs but they're pretty pricey (~$145 USD each), and I don't think the load from just 2 5830's will keep another 750W at peak efficiencies.

So considering a budget of ~$150 total, can anyone recommend a pair of efficient PSUs, preferably somewhere in the 400-500W range?

True true.

Does OP want to tell us which 750W PSU so we can give a more specific answer?

Care to elaborate?  DSPs in many smart-phones / tablets / etc are geared around highly efficient, low power video stream processing - several of TI's newer chips can do 1080p without breaking a sweat for example.  Seems like that kind of stream processing architecture would lend itself handily to mining.. 

I wouldn't expect to get double-digit MH/s out of them or anything, but my understanding was that they were usually glorified FPGAs.

Maybe I missed while skimming the thread, but has anyone tried this on 69xx series hardware?

Curious if this gets around the 'memory clock must be >= gpu clock - 125mhz' issue..

Someone indicated in another thread they were able to use it successfully on a 6990, I'm more curious about 6950 / 6970's

5850's should have a TDP around 150W

150W * 3 = 450W

Unless the rest of your PC is somehow slurping down 300W you'll be fine.  Accounting for the rest of an 'average miner' system - low wattage CPU, mainboard, 1 or 2 sticks of RAM and maybe an HDD, it shouldn't be pulling more than 100W without the cards.

This should put you right in the sweet spot of that 750W PSU's efficiency.

I think if they'd bothered to use glue it'd still be intact

Too hot.

The rest are OK in my opinion, but 100C sustained temps are not so great.

Mine all range in the high 70 - low 80C range and I'm comfortable with that.

Consider that most cards will thermal throttle at ~110C, and you can see how that might be a little too warm.