Mobo recommendation please...

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Waltjie

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Hi guys and girls...

So, I want to use CrossFireX so I can use 2 x HD7850's. However, my current Mobo, whilst it is 'technically' ready, has only 1 x PCIe 3.0 (x16) and the other is a 1 x PCIe 2.0 (x4).
If I'm correct, this will not do?
So my question is, what mobo can you guys recommend, the cheapest possible, so that I CAN make use of CrossFire?

Thanks in advance!
 
That will actually do just fine. The performance hit on a x4 vs x8 vs x16 is so tiny and you really shouldn't worry about it.
 
Waltjie said:
Hi guys and girls...

So, I want to use CrossFireX so I can use 2 x HD7850's. However, my current Mobo, whilst it is 'technically' ready, has only 1 x PCIe 3.0 (x16) and the other is a 1 x PCIe 2.0 (x4).
If I'm correct, this will not do?
So my question is, what mobo can you guys recommend, the cheapest possible, so that I CAN make use of CrossFire?

Thanks in advance!
Click to expand...
It sounds like your mobo is capable. What model is it?

AsRock has good value mobo's in which you can crossfire. I recommend the AsRock Z77 Extreme 4, however, if it is too much for you, then you can look at cheaper alternatives (go look at Rebeltech for pricing). I suggest that you take a better performing motherboard (like the Extreme 4) if you consider crossfire, it is also a great board if you want to overclock :)
 
@Almighty - Thanks, I've done a fair bit of Googling on this matter now, and it seems you are right!
@EmileS - I have a MSI Z77A-G43
 
Waltjie said:
If I'm correct, this will not do?
Click to expand...

There is a slight performance drop, but it will work in x16 and x4 mode. Buying a new board for Crossfire is a little bit expensive though and getting one that splits 16 PCI-E 3.0 or 2.0 lanes into two x8 ones isn't something easily done on Intel boards, you're more likely to have luck with an AMD one. But for LGA1155, this is what you should be looking at:

MSI Z77A-G45 @ R1427

To my knowledge, that's the cheapest board that is capable of x8/x8 signaling on the top two PCI-E slots. Other Z77 boards in the same price range are usually only capable of running in x16/x4 mode, which isn't very good, but it's the compromise they've settles on because not a lot of people use Multi-GPU. If you're looking for something of slightly better build quality, there's the ASRock Z77 Extreme4.
 
So, I got my second 7850 today, and I've installed it. Ran some benchmarks (3DMark and also in-game) and it seems to make at least a 50% improvement thus far!
 
Waltjie said:
So, I got my second 7850 today, and I've installed it. Ran some benchmarks (3DMark and also in-game) and it seems to make at least a 50% improvement thus far!
Click to expand...

Nice, post some comparison scores up! A lot of people have boards with the same layout as yours, so they'd be just as interested.
 
Depends on what chipset and CPU you're aiming for, as well as what size case you want to stuff it into.
 
Okay so further to my CrossFire experience thus far...

Here are two screenshots from GPU-Z:

gpu1_zpsdf4839db.gif

gpu2_zps056de88e.gif


The first is from my first card, and the second from the secondary. Now, I can't help but wonder, is that MASSIVE difference between bus-width from card 1 and card 2 not really something to worry about, or does it mean that the second card is indeed being held back?
 
Huh, it's running at PCI-E 1.1 speeds. That's a bit odd. GPU-Z may not be reading it correctly though, but the 50% performance improvement you claimed makes it appear that it is working.
 
To save power, the pcie slot may be clocked down to 1.1, or 2 from 3 or 2. Run a program that utilizes crossfire to confirm max pcie speed.
 
reactor_sa said:
To save power, the pcie slot may be clocked down to 1.1, or 2 from 3 or 2. Run a program that utilizes crossfire to confirm max pcie speed.
Click to expand...

Ah ha! You are so right! Off course! When idle, and not running any program which utilizes CF, the second card powers down to PCI 1.1... Ive just checked this again, running Borderlands 2. The second cards immediately powers up, and it enters 2.0 with the bus width showing at 256 Bit.

Thanks guys! Im chuffed then, since in-game the magic of CF really is very apparent!
 
ScottulusMaximus said:
Double the price for 50% improvement... Always been my issue with SLI/Crossfire
Click to expand...
It is still worth it in many cases!

If you don't go for SLI/CrossFire, then you'll have to sell your previous card, which is a hassle. Secondly, you may have a time during which you have no working PC at all because you've sold your card before you bought the new one due to a money issue.

In the games that I'm playing I'm getting about 70-80% speed increase with my 2x GTX460's, which set me back much less than what a single (and slower) GTX480 would've been at that time, which was about 150% more than 2x GTX460's + its performance is a lot less in the games that I'm playing than the dual graphics cards.
If you're planning on a big upgrade, that would involve like a motherboard and CPU upgrade, then I'll rather recommend sticking with a single graphics card, because then you are going to be without a PC for a while and you have to go through the process of selling the components in any case!

I quite like the looks of having 2 graphics card in my PC, even though they're no where near the performance of a single GTX680! It just make your PC look so much more hardcore :D

The performance that I've measured (in 3D Mark and games) with my 2x GTX460's were very much the same (not even 1% off) when I ran them in PCI-E 2.0 16x + 4x slots (MSI X58A-GD65) vs. PCI-E 2.0 16x + 16x slots (Asus P6T Deluxe v2 that I have now).
 
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