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7870 Crossfire and PSU

post #1 of 7
Thread Starter 
So I decided I want to CF 7870s. I already have an ASUS DCUII but I was wondering if I could buy a different brand and have it work? The MSI on Newegg is about $20 cheaper and it looks to be just as nice. Does anyone know if these run as cool and quiet as the DCUII? I also have to order a new PSU since my 550W will buckle. I am seeing 2 7870s as eating 500W under load in review sites? I run an 8350 at stock speeds so I guess I will need a 750 or 850W PSU?
post #2 of 7
A good quality 500 watt will run 2 7870s easily. I would go for 550-600 just to have the headroom for overclocking. As for the card brand, it doesn't matter. Any 7870 will do. Ideally, you want the same one if you're overclocking. You'd have a higher chance of them being around the same, overclocking headroom wise.
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Gaming PC
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Asus G750jw
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CPUMotherboardGraphicsGraphics
Core i7 3770k  ASrock Extreme4 P67 Sapphire Dual X OC 7950 Sapphire Dual X OC 7950 
RAMHard DriveHard DriveCooling
8GB Corsair Vengeance 1866 Kingston V300 240gb (OS) Seagate 1tb (data) Corsair H60  
OSMonitorMonitorPower
Windows 7 Ultimate Samsung S27C750P 75Hz A-MVA Dell S2340m (x3) Corsair TX850 
CaseAudioAudioAudio
Azza Hurrican 2k ODAC Hifiman HE-500 O2 amp 
CPUGraphicsRAMHard Drive
Core i7 4700HQ GTX 765m 8GB DDR3L 1600 Corsair Force 3 120gb SSD 
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HGST 1TB Cooler Master Notepal U3 Windows 8.1 17-inch FHD 
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post #3 of 7
Thread Starter 
LOL, this is why I signed up for this site. I get quick responses unlike other sites where I get nothing. Here is my PSU:

http://www.newegg.com/Product/Product.aspx?Item=N82E16817207013&Tpk=xfx%20550

Damn I just checked my PSU now and it doesn't have 2 more 6 pin connectors only 4 pins. I am surprised that 500W could run those and an 8350. I read around and saw that power usage in those reviews isn't what it actually draws but it still seems like it would be sweating.

Anyways, I currently use ASUS Gpu Tweak to OC but I have heard of people using MSI afterburner. Chances are that the two of them will be so fast that I will have no need to OC them. I saw a benchmark at techspot(?) and in many new games such as Crysis 3, the 7870s beat out even the Titan in many games. AMD also released 13.11 beta 7 a few hours ago(just hours after I install beta 6 go figure) and it claims to be up to 20% faster for CF scaling.
post #4 of 7
Why dont get.2x 7950 instead? They would neeed a 700/750w psu

Hd7870Cfx performs as good as gtx titan...7950CFX.outperforma gtx titan by 5 to 20fps
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Wanted: Wanted: R9 290/X/R9 390/X
$165 (USD) or best offer
  
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post #5 of 7
Maybe because he already has one 7870? It woul be cheaper to pick up a seconde one rather than 2x 7950.
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post #6 of 7
If your 7870 is a light Tahiti, in another words: 7870XT , you can CF it with 79xx series
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Sandisk 120 GB Extreme Sata III 2 TB WD Intellipower Green External converted t... 4 TB WD 5400 RPM Green Internal Xigmatek Loki 
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Win 8.1 -64 bit Philips 190vW D-sub 1440x900 LG 29'' 2560x1080 Logitech Cordless Internet Pro 
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post #7 of 7
Thread Starter 
Ok, apparently there was a sale that I missed because that MSI that cost 150 yesterday is back up to 220 today before MIR. That really pisses me off. The issue with the 7950 is that they are going for 300. That would mean 600 for CF plus another 80 for the PSU. In that case I would just buy dual 280x's. That is way out of my price range. If the 7870 goes on sale again, I could CF with a new PSU for ~250.
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