Crossfire with a pci-e 3.0 4x should i worry?

[Dadaum]

Hello everyone, i recently got back with my trip to US and came with a Z97-G95 gaming from the MSI and another r9 290. All looked well, but when i started to assemble my PC i have discovered an ugly truth. The middle one PCI-E 3.0 from the MOBO, isn't working and does not even reconize the gpu.So i decided to put on the last the second gpu on the last slot and that run's at 4x (and on the first one at 8x). Should i worry? this will affect my performance?

picture below its showing how my pc is assembled.

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Shouldn't affect it very much if it even works at all.

[Thebman712]

nope, 4x is fine for graphics card

[Octavialicious]

PCIe 3.0 4x is PCIe 2.0 8x, which is more then fine. Don't worry about it

[Dadaum]

Thank's to everyone that responded! another question: I have 2 monitors should i put one input on each card?

[zlolslavez]

Thank's to everyone that responded! another question: I have 2 monitors should i put one input on each card?

put both in 1 card i believe

[i_build_nanosuits]

yes pcie 3.0 at x4 speed will limit the performance of your cards by a very noticeable amount actulay in that configuration both card will run at x4/x4...this config limit even an HD7970 (r9 280x) so of course it will limit a 290 crossfire even more:

http://www.anandtech.com/show/5458/the-radeon-hd-7970-reprise-pcie-bandwidth-overclocking-and-msaa
Moving from PCIe 2 x16 (8GB/sec) to PCIe 2 x8 (4GB/sec) does incur a generally small penalty on the 7970. However like most tests this is entirely dependent on the game itself. With games like Metro 2033 the difference is non-existent, while Battlefield 3 and Crysis only lose 2-3%, and DiRT3 suffers the most, losing 14% of its performance. DiRT3’s minimum framerates look even worse, dropping by 19%. As DiRT3 is one of our higher performing games in the first place the real world difference is not going to be that great – it’s still well above 60fps at all times – but it’s clear that in the wrong situation only having 4GB/sec of PCIe bandwidth can bottleneck a 7970.

 

...ultiimately what is clear is that 8GB/sec of bandwidth, either in the form of PCIe 2 x16 or PCIe 3 x8, will be necessary to completely feed the 7970

 

x4/x4 pcie 3.0 is recommended only for r9 270(x) gpu's or slower.

[Dadaum]

yes pcie 3.0 at x4 speed will limit the performance of your cards by a very noticeable amount actulay in that configuration both card will run at x4/x4...this config limit even an HD7970 (r9 280x) so of course it will limit a 290 crossfire even more:

http://www.anandtech.com/show/5458/the-radeon-hd-7970-reprise-pcie-bandwidth-overclocking-and-msaa

Moving from PCIe 2 x16 (8GB/sec) to PCIe 2 x8 (4GB/sec) does incur a generally small penalty on the 7970. However like most tests this is entirely dependent on the game itself. With games like Metro 2033 the difference is non-existent, while Battlefield 3 and Crysis only lose 2-3%, and DiRT3 suffers the most, losing 14% of its performance. DiRT3’s minimum framerates look even worse, dropping by 19%. As DiRT3 is one of our higher performing games in the first place the real world difference is not going to be that great – it’s still well above 60fps at all times – but it’s clear that in the wrong situation only having 4GB/sec of PCIe bandwidth can bottleneck a 7970.

 

...ultiimately what is clear is that 8GB/sec of bandwidth, either in the form of PCIe 2 x16 or PCIe 3 x8, will be necessary to completely feed the 7970

 

x4/x4 pcie 3.0 is recommended only for r9 270(x) gpu's or slower.

its a the first gpu is running 8x  and the second one is running 4x

[Cheddle]

Hello everyone, i recently got back with my trip to US and came with a Z97-G95 gaming from the MSI and another r9 290. All looked well, but when i started to assemble my PC i have discovered an ugly truth. The middle one PCI-E 3.0 from the MOBO, isn't working and does not even reconize the gpu.So i decided to put on the last the second gpu on the last slot and that run's at 4x (and on the first one at 8x). Should i worry? this will affect my performance?

picture below its showing how my pc is assembled.

 

uggh the feels.

 

 

This DOES have an impact on performance - I tested it myself.

 

Here is my old thread from October when I was asking this same question (I answered it myself by buying an SLI board)

 

http://www.tomshardware.com/answers/id-2312541/crossfire-290-pcie-0x16-0x4-bottleneck-res.html

[Cheddle]

TLDR;

the difference in performance is measurable - the average FPS speak for themselves but the biggest issue was on 16x/4x is that I got suttering like a mofo, the AVG fps is being dragged down by the STUTTERS

 

The Z97 is running pcie 3.0 16x/4x (over chipset)

The Z87 is running pcie 2.0 8x/8x (direct to CPU via Nvidia certified SLI goodness)
 

tomb raider:
z87 = 66.7
z97 = 65.9

metro last light
z87 = 47.39
z97 = 42.86

unigine valley
z87 = 98.8
z97 = 94.8

firestrike gpu score (may be slightly different clocks on core in these (977 MHZ VS 1000MHZ) and z97 was with 14.7rc3 - z87 with 14.9)

z87 = 20,768
z97 = 18,881