UK - help me select some GPUs

[dazza12]

I've been giving myself a bit of a headache over the last couple of weeks trying to work out a combination of cards that will give me the maximum bang for my buck, but with little success.

I've got approximately £1000 in Amazon vouchers. In addition, I've got an Amazon Prime membership. As a result, I'd prefer to shop there to make the most of what I have available.

I've got everything else - a Gigabyte 990FXA-UD5 Motherboard, 8Gb RAM, 1Tb HDD (but may change this for a small SSD), a CoolerMaster HAF-XB case with fans everywhere. What I'm missing is the PSU and GPUs. This is where I need help.

This rig is for Scrypt mining, not interested (yet) in ASICs.

For OS, I have a Windows 7/8 licence available or can use Linux. If one has advantages over the other for any particular card (driver etc.) I'd be happy to use either.

I'm potentially looking to expand in the near future, and might add a card or two to whatever's installed, so any PSU choice will need to take this into account. From my own research it looks like the maximum I could get on the funds available are 2 cards, so I'm assuming PCI-X risers won't be important at this stage.

What is the best that I can get for my money, bearing in mind the above?

Thanks in advance for any pointers.

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[tom_o]

6x750Ti or 6x R9 270OC are the best bet unless you want to loose money by the end of the year at latest because of power consumption. UK electric prices are much higher.

[AngelSky]

You can calculate everything yourself based on the performance reported by others. Just try to get the best Khash/£ ratio.

Depends on the prices/availability of what you plan to buy on Amazon but you may come to the R9 270x OC.

[Wipeout2097]

Not from amazon, but see if this is worth it:

R9-280x,  207£: http://allshop-online.co.uk/index.php?id_product=34969&controller=product
R9-270, 130£: http://allshop-online.co.uk/index.php?id_product=33920&controller=product

[tom_o]

You can calculate everything yourself based on the performance reported by others. Just try to get the best Khash/£ ratio.

Depends on the prices/availability of what you plan to buy on Amazon but you may come to the R9 270x OC.

Really no, you want the best efficiency at UK power prices of £0.15-£0.20kwh

[dazza12]

Thanks guys.

Been looking at the R9 270OC, looks just like what I need. I'm assuming this one here is good? http://www.amazon.co.uk/gp/product/B00GNE0CHI/ref=ox_sc_sfl_title_1?ie=UTF8&psc=1&smid=A3P5ROKL5A1OLE

Been hearing conflicting reports on how to arrange them on the motherboard (Gigabyte 990FXA-UD5). It's been suggested that all the cards need 1x16 risers, to stop any bandwidth issues. Is this correct or can I still use the existing x16 slots on the board? Any recommendations on particular risers so I don't end up killing the cards?

[tom_o]

The board slots are good, but you won't get 6 to fit. With AMD cards you won't have any performance drop on 1x-16x risers, the USB ones are less than a tenner now on ebay and have bolt holes for easy mounting, this card is light enough to be supported by just the PCI-E slot.

Risers are mostly to keep the card cool, but I have one of those exact cards sat in the PCI-E slot of a BTC Pro with a suspended 280X on either side of it and it mines away at 425Khash at 2500RPM at 74 degrees. Can do up to 480Khash but mine gets crashy at those speeds. The sapphire toxics can reportedly do 560!

And ebuyer have the Gigabyte card for a fiver less!