Originally Posted by Vencenzo
Originally Posted by KyadCK
It would be useless as one. it's just a 7850.
Easier to just get a 7870 for $150 or so and use that, at least it'll be worth something in terms of mining power. A pair of Windforces (1100/1200 clocks) are good for about 900 KH/s.
Still want to try this myself. Your probably right on sheer hash rate, but the the bottleneck with lightcoin is system ram-vram latency. HSA's specialty. Ps4 should be the most efficient miner power/khs. Already know my limits with the fx chips and no word on a fx steamroller. Nothing better to do.
My 7870s gets ~450 KH/s each.
My 7990 gets about 675 per die, totaling at 1350 KH/s.
My 7970 gets about 650 KH/s.
My system RAM is at 1600 10-10-10 (substitute kit), and all cards are running in effective 2.0 x8 mode with the exception of the 7870s which are on 3.0 x16 mode. KH/s is the ONLY value of importance. Whatever is holding you back from higher numbers, THAT is your bottleneck. It's always Core and VRAM speed, never bandwidth.
This is actually one of the few kinds of GPGPU work that is NOT latency sensitive. CGMiner uses nearly no CPU time or System ram. Like Folding and Bitcoin, a work unit is passed to the GPU for a while so it can work on it. When it's done, it's given back to the server of the pool you're mining for. They work on these loads for multiple seconds (sometimes nearing a minute), making actual GPU transfer times very little.
Power efficiency can matter... For example a GTX 580 pulls in 250 KH/s with it's 250-300w usage, barely making $145 per month* while costing $21 on power (in Chicago). But in comparison, my 7990 at 360-375w can pull in 1350 KH/s, making $807 per month* while costing "just" $26... But again, I could cut my card's efficiency in half and it would be just fine.
The most efficient miners are GCN 1.1. That would be the 7790, which is worthless for it's price, the 7990 which has problems cooling itself under real litecoin load, and the 290/290x which have throttle issues and are expensive for the potential hash rate. All of which are GCN 1.1 and are better then normal GCN cards.
Not that it really
matters, because the current difficulty and value of litecoin even normal GCN is quickly profitable, especially if you already own some for gaming and don't need to invest. Cards slower than the 7870 are simply not worth it however, as under that compute power starts to drop off. 7950s are at a good price-to-hash ratio if you can get them sub-$250, but if you can't afford the power bill you have no business investing in GPUs to mine anyway.
For the record, a full stock 7850 (See: PS4) pulls in an abysmal 300 KH/s (About as good as a 6870)... While it would be as power efficient as a 7870, it is not cost efficient, as the 7870's additional clocks and cores give it far more of a lead then there is price difference between the cards.
My 7870s mine 24/7 and my 7990/7970 mine when sleeping/working/not there. I'm not speaking theoreticals, I'm speaking experience.
*At current Difficulty and LiteCoin value. Will probably change in the next 5 minutes.