P7P55D LE Crossfire help

Caporegime
Joined
17 Jan 2010
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weston-super-mare
Its running at 4X as there is not enough pci-e lanes to go around, the slot is a physical 16X in size but is electrically connected at 4X.

The p55 chipset only has a limited number of these "lanes" to go between all the slots and other control chips.

there is no way of altering this.
 
Associate
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2 Aug 2010
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Sheffield
The difference is pretty substantial, to the point where it is widely regarded as a waste to try to run Crossfire on this board; although it is advertised as Crossfire ready in reality it is a single GPU motherboard. Possibly for someone wanting a strong single GPU and a lesser nVidia card for PhysX or CUDA.

If you already have the cards to Crossfire with, just try it. It lets you shift between single GPU and Crossfire quite easily, so you can make up your own mind. However if you only recently got it and you want to have an actual Crossfire setup, I would return the motherboard for one that does 8x/8x.
 
Soldato
Joined
23 Apr 2009
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11,973
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Cheshire
Are there any p55 mobos with 2 16 slots? running at x16?

With standard configuration P55 boards the limit is x8x8. However, with the use of an Nforce 200 chip two x16 lanes can be provided from this - so boards using this chip can run dual graphics cards at x16 speeds.

None of these boards are available on OCUK, one example is called the Gigabyte P55A UD7. The main drawback of these boards is the price - they are usually closer to £200 than £100 and the performance difference between dual GPU x8x8 and x16x16 is very small as usually x8 speed is enough for a modern graphics card.
 
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OP
Joined
22 Jan 2010
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421
Location
Brighton
With standard configuration P55 boards the limit is x8x8. However, with the use of an Nforce 200 chip two x16 lanes can be provided from this - so boards using this chip can run dual graphics cards at x16 speeds.

None of these boards are available on OCUK, one example is called the Gigabyte P55A UD7. The main drawback of these boards is the price - they are usually closer to £200 than £100 and the performance difference between dual GPU x8x8 and x16x16 is very small as usually x8 speed is enough for a modern graphics card.

Ok thanks for the info, Could you suggest a good 8x 8x board :D?
 
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