Good value GPU's?

[xIronCrossx]

I don't really have too much money right now, but am wondering what is the best hashing card under $200? Are the R9 270's or 270x's any good? 7850? 7870?

I already have 2 7950s hashing away, but I need more space in between them since I have a micro atx mobo so I need one x16 to x16 riser and one x1 to x16 powered riser.

Also, can you use x1 to x16 powered risers in x16 slots? If not, where can I find decently priced x16 to x16 risers? Thanks!

[mattopia]

I can't speak to risers, I've been afraid to use them and refuse to pay current prices for them.  (I have a few 16x to 16x unpowered that do the job of separation just fine though)

As far as cards, the 7790 is under $100 typically and puts out about 225-235kh/sec, and by my calculations (based on the litecoin hardware page), the 7790's have the lowest power draw (over 3kh/sec/watt).  You could squeeze 4 of them and a motherboard/cpu comfortably on a 450-500 watt p/s.

The 270x is over 450kh/sec and they can be found for under $200. 

[xIronCrossx]

Yeah I only have 3 total slots right now on my micro ATX mobo. The 2 x16 slots are filled with the 7950s, I'm gonna use a powered x1 - x16 for one since they are way too close together and cause heat problems for the one card. I just bought an r9 270x and am gonna use that with the second x1 - x16 riser in the x1 slot. Should net me over 1.5 mh/s and make me a happy miner.

[zvs]

I get ~250khash from my 7790's @ a little under 60 watts each

(im sure I could bump them up some, since they're running at like 50-55oC to achieve that)

[xIronCrossx]

Maybe I'll get some of those next month, if I can fix up my old x58 system. That has 5 slots, so that wouldn't be too bad, plus 5 * 60 is only like 300 watts, so I would only need around a 500 watt PSU(in case, plus x58 is kinda power hungry). Let's see how this month goes.


Also, does anyone have any example of a config with multiple cards? Or should I just run 3 instances of cgminer?

[kalus]

I can't speak to risers, I've been afraid to use them and refuse to pay current prices for them.  (I have a few 16x to 16x unpowered that do the job of separation just fine though)

this is a good point.  4 risers @ $25 a piece is the price of a new motherboard.  people are throwing out 5 year old 'useless'  core2duos that are no problems for mining.  I was hoping that ASRock btc mining motherboard would ahve come with risers, but for 99 bucks you get the same motherboard as everyone else, just with a pile of 1x ports glued in.