How Many Watts Shall I Get?

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Sorry been a bit busy.

If you want to use multiple graphics cards with an Intel CPU, your best bet is almost always a Z-series motherboard as this usually means it has the capability to split the bandwidth of the x16 slot into two (basically your two x16 slots run at x8 speed). You can get away with a PCIe 3.0 running at x4 speed, especially if you are running lower level cards which are unlikely to need the extra bandwidth, but most (possibly all) non-Z series boards use PCIe 2.0 x4 speed (equivalent to PCIe3.0 x2) for the second x16 size slot. Sorry if that's complete gibberish, the terminology can be pretty confusing as the terms like "x8" are used to represent both the physical size of the slot, and also the speed it is capable of...

Rammy

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You can't SLI on a H97 motherboard (you need a Z-series) so your power needs are significantly lower if you already have the rest of the parts. Crossfire is slightly different in that the standards for being "crossfire ready" are significantly lower, but the board you have only runs it's second PCIe slot at 2.0 x4 - it's going to mean the second card is somewhat limited and not really a good idea.

For a single R9 280 you only need 500-550W.
For crossfire R9 280s, you need around 750W.
Anything by Seasonic or XFX is a safe bet. The Antec HCG-M models are also nice.
 

aschoneveld

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so are you suggesting I should get a z series motherboard? and If I do will it solve all my problems? and what PCIe slots should I have? you have been far more helpful than I could have thought! thanks
 

aschoneveld

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???
edit: anyone else willing to help? (I will not be going crossfire anymore too)
 

Rammy

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Sorry been a bit busy.

If you want to use multiple graphics cards with an Intel CPU, your best bet is almost always a Z-series motherboard as this usually means it has the capability to split the bandwidth of the x16 slot into two (basically your two x16 slots run at x8 speed). You can get away with a PCIe 3.0 running at x4 speed, especially if you are running lower level cards which are unlikely to need the extra bandwidth, but most (possibly all) non-Z series boards use PCIe 2.0 x4 speed (equivalent to PCIe3.0 x2) for the second x16 size slot. Sorry if that's complete gibberish, the terminology can be pretty confusing as the terms like "x8" are used to represent both the physical size of the slot, and also the speed it is capable of running at. If you aren't planning on running multiple cards then obviously this isn't terribly relevant, but hopefully it clears up any confusion.

If you are sticking with a single R9 280 and don't intend to add a second, then your original motherboard is absolutely fine. There are cheaper options, but it's got a good feature set going forwards.
As I said before, you only need a 500-550W PSU for an R9 280, and any quality model will come with the prerequisite one 8pin and one 6pin PCIe power cables required for the card. There aren't a lot of models on the Australian market that I like the look of, but if it were me I'd probably be looking at the Antec HCG-520M or 620M. The 520W version is sufficient, but given the closeness in pricing I'd definitely be tempted to spend a little extra and get the 620W even though it's unlikely to be useful.
 
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aschoneveld

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i thought id ask you again:)
but on the sapphire website it claims an r9 280x gpu needs 650ish watts, but people are suggesting 550w. so what should i get?
 

aschoneveld

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^^^^
 

Karadjgne

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You'd have to understand where recommendations come from. There are several classes of psu, quality, decent, ok and junk. The actual outputs of the junk psu's are so dismal and pathetic, that if your pc required 550w from a decent psu, you'd be well advised to get a 700w from the junk list. Gpu manufacturers know this, so to cover their butts they'll recommend worst case scenario, or in your case that's 650w. Reality is you could easily use a lot less.

100w for cpu, 100w for mobo and accessories, 75w for pcie, 225w for gpu. So you could use a 500w - 520w quality, 520w - 550w decent, 550w - 600w ok, or 600w-650w junk as a minimum. The Antec HCG m are quality, and have the correct connectors, could use either 520w or 620w, same with the Seasonic, for Corsair CX, they are OK, so a cx600 would be a choice, or a HX/TXv2 550w would be better.

Hope that helps some.

Edit: the average r9 280 requires 25a on 12v and 500w minimum. The Antec HCG 520w M has 38a and 520w. Same as Seasonic 520w M12-II which is the same design (Antec HCG-M is built by Seasonic)
 

aschoneveld

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sorry, i hadn't realised you had replied till now. thanks!
could you also tell me if there are any good modular/semi psu @550+watts for under $80? AUD? if not can u suggest the the cheapest one you can think of?
 

Karadjgne

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