Buying a 7970 an ok idea? gaming and btc

[Ocean]

time for upgrade

but since i have been bitcoin mining i could double my rate by buying one, (if i keep my current cards for 2 and 3, (non crossfired))


ive been considering dumping crossfire for compatibility reasons, and i would like to just get 1 7970 for gaming, and then keep both 5850s i already have for mining during non usage in slots 2 and 3.


would a $400 7970 1100Mhz be a horrible idea? saw a triple fanned gigabyte that caught my eye.


any glaring shortcomings based on my current hardware would be appreciated

 

[Ozymandias]

A 7970 is great for gaming at 1080p or 1440p. I have no experience with mining, so I can't comment there. My only concerns with your setup would be heat and power. The 3 fan Gigabyte 7970 is going to dump heat into your case, so if you have non-reference 5850s that do the same, it's going to get hot. On the power side, the Corsair HX750 is a fine PSU but an overclocked 7970 can draw 300w on its own. AnandTech saw 550w from 2x5850s and a 920 @ 3.3GHz under heavy load and your 930 is at 4.0GHz. So you might need to drop your CPU overclock to get everything running smoothly if you mine with all three cards.

 

[[G]Ernesto]

I am unsure if your powersupply will be able to handle 2x5850 and a 7970, it also depends on your motherboard how much the load will be there and how many extra powercords you can plug into the MB.

Graphiccards draw some of their power from the motherboard, like this (To a hard max of 75w):

No PCI-E: 100% from MB
1x6-pin: 50% from MB
2x6-pin: 33% from MB
1x6-pin+1x8-pin: 25% from MB
2x8-pin: 20% from MB

Without looking things up how the connectors look, in theory, you can look at 75w x3 from the motherboard in powerdraw.

24 + 4pin on MB = 150w
24 + 8ping or 4x2 pin on MB = 225w

Processor can take 90w from 5v rail, rest comes from the 12v pool.

So if you have an overklocked processor, that takes 100w full load, and use 2x 7970 that are overklocked and use 150w from the motherboard, well, then you are 10w short on a common motherboard (non eatx) and your system will crash or go unstable in other way under full load of CPU and GPUs.


Something like that. Zcenix made some great post about that, but it's not in English.