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7870 crossfire on PCIE 2.0/Z68 perfomance hit???

Last response: in Systems
May 11, 2012 10:57:10 PM

Hi Guys,

I am helping out a friend and building a PC for him next weekend.

We are sticking to a Sandy bridge build and we have all the components set up. Here is the configuration we are looking at:
i7 2600K
Gigabyte GA-Z68XP-UD3R 32GB DDR3
Corsair 8GB
Sapphire 7870 OC edition 2GB
Corsair HX 650
Corsair H100 ( Black)
Corsair 500R
Corsair Nova 60 GB SSD

I have highlighted the motherboard because of a couple of things. We are a bit concerned about her. The reasons we are looking at that board is:
- Its black and matches our overall build. Aesthetics are VERY important.
- 2 PCIE 2.0 slots running at X16 or X8/X8
- Overclocking

Now, the problem I am reaching out to you guys is because we obviously want 2 PCIE slots so that we can add a second card later a year or so later. But, the main question is will a PCIE 2.0 board reduce crossfire performance for compared to a PCIE 3.0 board?

I was looking at a couple of threads and am well aware that lanes do not saturate. Picture link below.

But I have also read that the 7970 on a Z68 is taking a 10-15% hit in performance somewhere recently. I cant find the article anymore. :-(

Pricing is critical and I cant buy a better board for the chap and he needs a 2600K in his build for rendering. The GPU is also set as we are getting a sweet deal via a friend.

Will cross firing hit our performance in the future? Or will we have to kill something and buy a more expensive Z77 board?

Any advice would be helpful. Cheers!!!!

May 11, 2012 11:12:32 PM

Also, correct me if I am wrong.

But PCIE 3.0 = 2 x PCIE 2.0

So does that mean that a PCIE 3.0 x4 = PCIE 2.0 x 8 right? Does this mean that even crappy entry level Z77 boards will have the same performance as a say, Z68 x8/x8 board?

a b B Homebuilt system
May 11, 2012 11:12:37 PM

You just answered your question by providing the link.
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a b B Homebuilt system
May 11, 2012 11:15:28 PM

Performance hit caused by older PCIE generation 1.1 and also the X4 speed, anything else doesn't affect the performance
May 11, 2012 11:30:48 PM

Best answer selected by mailpranshu.
May 11, 2012 11:31:04 PM

Thanks a lot mate...

Closing out the thread.