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Buy a second HD 7870 for xfire or upgrade to single 7950-7970?

Tags:
  • Crossfire
  • HD
  • Graphics
Last response: in Graphics Cards
September 14, 2013 11:38:58 AM

Hello!

Here is my current system:
http://pcpartpicker.com/p/1oBQw

Processor: I5 4670k
GPU: XFX hd 7870 Ghz edition
MOBO:Asrock Z87 Extreme4
PSU: Corsair Builder CX 600W 80Plus Bronze
Ram: Corsair XMS3 8gigs



I would like to hear your guys thoughts on the following:

As we go into next generation gaming what is better for performance?
Buying a second hd 7870 to crossfire or upgrading to a 7950 / 7970

It seems that if I choose crossfire I will need to
1)Buy a PCIe adaptor to have 4 PCIe connector or
2)Buy a new PSU

I would love to hear you guys thoughts

Kind regards :bounce: 

More about : buy 7870 xfire upgrade single 7950 7970

September 14, 2013 11:45:15 AM

Your link just goes to the regular 'build' page for me. If you don't have at least a 700W high quality PSU with about 50amps on the +12V rail(s) and 4 PCIe 6/8 pin connectors, you are better off staying with a single high end card. AMD right now has some issues with their CF and micro stutter. I have been testing the newest 13.10 beta driver for a bit with my 2nd system (i7-875K/HD 7870 CF) and find that the m-s appears to be gone for the most part. If you don't already have the 1st HD 7870, go for the HD 7950 or HD 7970 and a high end PSU.
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September 14, 2013 11:49:30 AM

I was in this situation about a month ago, considering whether I should get 2x 7850 or a new card altogether. I ended up getting a 7970, and I would recommend the same to you (Or a 7950). My reasoning: The Vram does not stack, so if you go for a high res setup, you could be out of luck with some games. I'm not sure whether microstuttering was fixed with 13.8/13.10, but there will almost always be issues, big or small, with multi-card setups. I'm not saying that they are bad, but a single high end card is usually better than two mid range cards. Oh, and the 7970 is only about $300 now.
Also, you would probably need a bigger PSU for crossfire, you might be able to get it to work with 600w, but it would be pushing it.
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September 14, 2013 12:00:37 PM

clutchc said:
Your link just goes to the regular 'build' page for me. If you don't have at least a 700W high quality PSU with about 50amps on the +12V rail(s) and 4 PCIe 6/8 pin connectors, you are better off staying with a single high end card. AMD right now has some issues with their CF and micro stutter. I have been testing the newest 13.10 beta driver for a bit with my 2nd system (i7-875K/HD 7870 CF) and find that the m-s appears to be gone for the most part. If you don't already have the 1st HD 7870, go for the HD 7950 or HD 7970 and a high end PSU.


Thank you for your response!
I edited my original post and I think I fixed the link issue.

Question for you though and this is why I been a bit confused.
I had others tell me that a 600w PSU with a combined 39 amps or higher on the +12v is enough to crossfire 2 HD7870.
My PSU has that, I would just need to buy the adaptor. However if I absolutely have to buy another PSU I will.

Also I already have 1 HD 7870 and I can't return it.

I do appriciae your response.
I'm just trying to hear people thoughts so I can understand things better so I can achieve the "best bang for the buck" per say =)
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September 14, 2013 12:07:36 PM

Apbg10 said:
I was in this situation about a month ago, considering whether I should get 2x 7850 or a new card altogether. I ended up getting a 7970, and I would recommend the same to you (Or a 7950). My reasoning: The Vram does not stack, so if you go for a high res setup, you could be out of luck with some games. I'm not sure whether microstuttering was fixed with 13.8/13.10, but there will almost always be issues, big or small, with multi-card setups. I'm not saying that they are bad, but a single high end card is usually better than two mid range cards. Oh, and the 7970 is only about $300 now.
Also, you would probably need a bigger PSU for crossfire, you might be able to get it to work with 600w, but it would be pushing it.


This is great insight! Thank you for your reponse and I will take your advice into consideration for my final decision. :D 

Question: So lets say a game recommends 3gig of vram and if you crossfire 2 cards with 2gigs of vram it wouldn't match the performance of a 3gig vram card?
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September 14, 2013 12:14:43 PM

If the vram limit is not exceeded, it will match (And sometimes surpass) something like a 7950/7970. But, in some games more than 2gb of vram is needed, and that is when you would want a 3gb card.
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Best solution

September 14, 2013 12:22:37 PM

Xhelios said:
clutchc said:
Your link just goes to the regular 'build' page for me. If you don't have at least a 700W high quality PSU with about 50amps on the +12V rail(s) and 4 PCIe 6/8 pin connectors, you are better off staying with a single high end card. AMD right now has some issues with their CF and micro stutter. I have been testing the newest 13.10 beta driver for a bit with my 2nd system (i7-875K/HD 7870 CF) and find that the m-s appears to be gone for the most part. If you don't already have the 1st HD 7870, go for the HD 7950 or HD 7970 and a high end PSU.


Thank you for your response!
I edited my original post and I think I fixed the link issue.

Question for you though and this is why I been a bit confused.
I had others tell me that a 600w PSU with a combined 39 amps or higher on the +12v is enough to crossfire 2 HD7870.
My PSU has that, I would just need to buy the adaptor. However if I absolutely have to buy another PSU I will.

Also I already have 1 HD 7870 and I can't return it.

I do appriciae your response.
I'm just trying to hear people thoughts so I can understand things better so I can achieve the "best bang for the buck" per say =)


Hi - Yes, a good quality 600w PSU with 39amps on the +12v rail(s) will power a system with 2 7870's.

Since you already own 1 7870, your least expensive upgrade would be to get another. But, see what you can
sell your 7870 for & think about a 7970 as the prices are dropping on them, and as Apbg said, even
tho the new beta drivers have a lot of improvement for CF, there will almost always be some issues.


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September 14, 2013 8:21:47 PM

Xhelios said:

Question for you though and this is why I been a bit confused.
I had others tell me that a 600w PSU with a combined 39 amps or higher on the +12v is enough to crossfire 2 HD7870.
My PSU has that, I would just need to buy the adaptor. However if I absolutely have to buy another PSU I will.

Also I already have 1 HD 7870 and I can't return it.



You may squeak by with that PSU and the adapters that come with the card, but that is cutting it close. Try it, and if you experience shut downs or re-boots, it probably means the card is over loading the PSU's +12V rail(s).

Each HD 7870 is a 175W card at max. (14.6A @ +12V). The Processor is another 7A at max. Overclocking either will increase that. The MB, drives, fans, lights all run off the +12V rail also. For best longevity, you should try to not run your PSU at more than 80% of its max capacity for extended periods of time. As in hours of gaming.
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September 15, 2013 6:27:46 AM

Hello,

Thank you all for your thoughts.
It seems that going for a crossfire set up on my current PSU isn't really optimal and I appriciate you guys taking your time to explain that to me.

I have a quick question. I think im going for the 7970. Would my PSU be enough?
I was looking at the 7970 and most of them have a 8pin/6pin power plug.
My current PSU has 2 6+2pin connectors. How would that work? connect 1 6pin and 1 6pin and add the 2 hanging ones to the plug?
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September 15, 2013 7:32:08 AM

Xhelios said:
Hello,

Thank you all for your thoughts.
It seems that going for a crossfire set up on my current PSU isn't really optimal and I appriciate you guys taking your time to explain that to me.

I have a quick question. I think im going for the 7970. Would my PSU be enough?
I was looking at the 7970 and most of them have a 8pin/6pin power plug.
My current PSU has 2 6+2pin connectors. How would that work? connect 1 6pin and 1 6pin and add the 2 hanging ones to the plug?


Yes, more than enough - enjoy!

The 2 pcie connectors from your PSU will plug into the card, you will just peel the
xtra 2 pins (you'll see) aside for the port accepting 6pins.
You'll use all 8 in the other port.

Oh, one other thing, when you decide on a 7970 (if that's the way you go), get it's dimensions
and insure that it will fit in your 200r case. It is a long card, many of them are over
11"(>279mm) long. Measure from the rear panel of the case along the pcie slot to
the 1st obstruction, which might be a hdd. You might need to move a hdd up or down.
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September 15, 2013 7:48:07 AM

Awesome thanks to all of you once again for your help!
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November 3, 2013 5:45:14 PM

I just had this same issue. Well, an i7 2600k with 7870 system. I was trying to decide if I should get a 2nd 7870 or just sell my existing one and get a single 7970. I went the single 7970 route because of what I have heard about crossfire micro-stuttering, the fact that some games don't make use of crossfire, the 3GBs that will be available on a 7970 for greater than 1080 gaming, and finally because of the black screen and 100% fan speed issues that some people seem to have with the 78xx series of cards.

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