# x16 x4 CFX



## Jaskanwar Singh (Jan 17, 2011)

guys ASUS P8P67 has x16 and x4 slot. ASUSTeK Computer Inc. - Motherboards - ASUS P8P67

then how is it able to perform nice in CFX - ASUS P8P67 and P8P67 Deluxe Intel Sandy Bridge Motherboard Review - ASUS P8P67 Deluxe and P8P67 AMD CrossFireX Scaling - Legit Reviews


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## Piyush (Jan 17, 2011)

thats pretty odd
16x and...4x!!!


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## asingh (Jan 17, 2011)

Jaskanwar Singh said:


> guys ASUS P8P67 has x16 and x4 slot. ASUSTeK Computer Inc. - Motherboards - ASUS P8P67
> 
> then how is it able to perform nice in CFX - ASUS P8P67 and P8P67 Deluxe Intel Sandy Bridge Motherboard Review - ASUS P8P67 Deluxe and P8P67 AMD CrossFireX Scaling - Legit Reviews



Board is a winner. Would be interesting to see the same tests on greater resolutions. Clearly shows that the lanes are 'not' getting saturated at all.


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## vickybat (Jan 17, 2011)

Has it something to do with the improved pch?


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## Jaskanwar Singh (Jan 18, 2011)

^^pch only provides 8 lanes for peripherals. the 16 lanes come from cpu. and i suppose asus has used some out of 16 for extra peripherals. only leaving x8 x4 for cfx. this is my asumption.

and why are these boards taking long to arrive here!!


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## vickybat (Jan 18, 2011)

PCIe allocation has been optimized in these boards so the lanes are not jammed all the time. I guess thats why we are seeing improved scaling even in reduced available lanes.


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## rajan1311 (Jan 18, 2011)

So maybe even on those mini ITX Brazos boards, stull like 5670s will not at all be bottlenecked on the x4 lane...

Good stuff Jas, you have been doing some good work! Keep it up.

Now, dont do the same mistake as I did, study well too!


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## asingh (Jan 18, 2011)

For this board concerned it will always have x16 x4. I doubt it can increase.


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## Jaskanwar Singh (Jan 19, 2011)

asingh actually it should be x8 x4. 

thanks rajan..


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## asingh (Jan 19, 2011)

^^
Not really sure, cause once the 2nd PCI.E is enabled to full link in the BIOS (x4) rest of the lanes for USB and likewise get disabled.


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## Cilus (Jan 21, 2011)

The performance difference between Crossfire of  X16-X4 mode, X4-X4 mode, X8-X8 and X16-X16 mode is very little, at least today's all current genration games.
The difference between X4-X4 CF and X16-X16 (X4 X4 is available is older gen PCI X 1.1 mobos with 16X 1.1 lanes as PCI Express 2X X4 provides the same bandwidth of PCI Express 1.1 X8) is maximum 8% in 1080P resolution in all the current games.
The difference between X8-X8 is actually less than 2% from the X16-X16 mode.
The discussed broad here runs at X16-X4 mode. So the performance difference will be more less.
This scenario has been tested with today's some of the top ends cards like GTX 460 or Hd 5870. Check the review of GTX480 scaling over here.


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## asingh (Jan 22, 2011)

^^
The lane saturation point is still to be reached.


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## ithehappy (Jan 24, 2011)

Pardon my noob query,
What does this x16 slot do? Is it just a PCI-E 2.0 slot or else?


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## vickybat (Jan 24, 2011)

^^ X16 slot refers to the number of lanes present to transmit data serially in a full duplex manner( to and fro). So x16 slot has total of 16 lanes present and are serial in nature. 

Data is transmitted and received between the end points of a link ( in this case, cpu & gpu). The 2.0 refers to bus speed.


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## asingh (Jan 24, 2011)

ithehappy said:


> Pardon my noob query,
> What does this x16 slot do? Is it just a PCI-E 2.0 slot or else?



Here you go.


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