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X48 vs P45 crossfire vs single card?

Last response: in Motherboards
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July 30, 2008 8:49:09 PM

Alright my maximus X38 mobo recently fried itself, probably due to me putting to much force on the PCB when installing my water cooling setup. However i was recently considering buying the new Biostar I45 board. As many of you may know this board holds the worlds highest FSB record but im yet to find a good review on it. I was just about to order it when i saw a post that said P45 can only allocate 8x 8x to its pcie2.0 slots, i currently have an HD 4870 and have 2 choices either go crossfire or return my HD 4870 and get an HD 4870 X2 when it is released.

My concern is that if i go crossfire i will be severely bottle necking my cards on P45 as shown here: http://www.tweaktown.com/articles/1472/7/intel_p45_vs_x...

But i noticed on the Biostar I45 board that you have to switch around jumpers in order for crossfire to work, i know no matter what that dual HD 4870s will be bottle necked but im wondering that maybe biostar did this so that if the jumpers are in non-crossfire postion that the main PCIE2.0 slot would receive full 16x bandwidth. If this is true than if i got an HD 4870 X2 it wouldn't be bottle necked.

Im basing that just on a guess but im wondering if anyone knows if that's true? Will P45 be bottle necked on a single card? Because if each slot is 8x bandwidth no matter what than i cant see why even a single card wouldn't be bottle necked.
July 31, 2008 6:09:29 PM

alright but will the board allocate all 16x bandwidth if im only using one card?

does that also mean that X48/X38 would allocate 32x bandwidth when only using one card?
August 1, 2008 12:11:56 AM

papasmurf211 said:
alright but will the board allocate all 16x bandwidth if im only using one card?

does that also mean that X48/X38 would allocate 32x bandwidth when only using one card?


no... think about it... you are only using one pci slot.... the motherboard will only read whats in the slot... so one card = x16

p45 mobos
if you want crossfire/sli = each card will run at x8 speeds
if you want single card = the card will run at x16 speed

x38/x48 mobos

if you want crossfire/sli = each card will run at x16 speeds
if you want single card = the card will run at x16 speed

:pt1cable: 
!