About crossfire and motherboard

[wong93]

Intel i7-3770k Processor
ASUS P8Z77-V LX Motherboard
Corsair AX 850Watt 80+Gold
Gigabyte HD 7970 Graphics Card(3 fans)
intel 520 ssd
4x4gb gkill sniper 1866 RAM
Cooler Master 212 evo


These are the specs I'm planning to get and I'm planning to get one more same GPU for crossfire configuration,but there's something which is bothering me

1) The motherboard specs said that it has

1 x PCIe 3.0/2.0 x16 (blue) *2
1 x PCIe 2.0 x16 (x4 mode, black)
2 x PCIe 2.0 x1
3 x PCI

So will I get full performance since one card will be at 1 x PCIe 3.0/2.0 x16 (blue) *2 and another at 1 x PCIe 2.0 x16 (x4 mode, black) ??


2) What's the meaning of x4 in the bracket?? cause it's a x16 lane,does this mean it limits the performance ??

 

[wong93]

It means that the black slot is physically a x16 (full-size) slot but it's only electrically wired to be x4, which means that this is not an ideal board for crossfire as the bottom card will be limited somewhat by that.

You should get something like this instead, which has a pair of PCI-e 3.0 x16 slots (I'm assuming they run at PCI-e 3.0 x8/x8 in crossfire, which is fine):
http://www.newegg.com/Product/Product.aspx?Item=N82E16813157293

thanks for the reply,but why do manufacturer do this? i mean making the slot x16 but only running in x4 mode?

btw, there's one thing that confuses me, are PCIE version and x kind of same thing?? like for example x1 means x1 speed and x16 means x16 speed and pcie version 2 is slower thasn pcie 3? ,are all of them related to speed only? and is PCIe 3.0 the only pcie that can run in x16 speed?



PS: is this one good? P8Z77-V LK

 

[wong93]

thanks for the reply, btw how well does your 7970 CFX scales in games?? and how does your ssd performs?