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Super n00b P55 PCIe Electrical Speed Question

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EarthDog

Gulper Nozzle Co-Owner
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If you have 2 GPU's it will break down to 8x/8x...Otherwise...no. What do you require at 8x?

What motherboard do you have?
 

petteyg359

Likes Popcorn
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Jul 31, 2004
EarthDog, some older motherboards (DFI Infinity P965-S) wouldn't split x8/x8, the second slot was only able to switch between x4 and x1, via a BIOS setting.
 

EarthDog

Gulper Nozzle Co-Owner
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Yep... but this is P55 with the controller on die. Different story I would imagine..No? (see title of thread)
 
OP
G

gwar2288

Member
Joined
Oct 6, 2009
It would be 2 GPUs yes.
The reason I ask is because I have a GA-P55-UD3 with an ATi 5850 atm, (Running in the x16(x16) lane) and it has a 2nd PCIe x16 slot, but it states x4 electrical.

I am not too fussed either way (from what I can gather the performance hit is only 5% or less), but just wondering :)
 

EarthDog

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With the 5850, a slower card, you may not see any performance decrease that was shown with a 5870 in 8x as the 5850 is more than the 1-2% slower than the 5870.
 
OP
G

gwar2288

Member
Joined
Oct 6, 2009
With the 5850, a slower card, you may not see any performance decrease that was shown with a 5870 in 8x as the 5850 is more than the 1-2% slower than the 5870.

I understand that :) My Question was mainly curiosity about whether crossfire would run at x16/x4 or at x8/x8.
 

EarthDog

Gulper Nozzle Co-Owner
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After reading a bit more, Im not sure I provided the right answer. I would suggest maybe PMing MIAHALLEN as he completed a review on this board and knows it pretty well.
 

Evilsizer

Senior Forum Spammer
Joined
Jun 6, 2002
crossfire will run on 16/4 but not at the same level as say a 8/8. the 4x slot even being pcie 2.0 may hold back the second GPU.
 

Neuromancer

Member
Joined
Oct 11, 2005
Location
Tau'ri
It would be 2 GPUs yes.
The reason I ask is because I have a GA-P55-UD3 with an ATi 5850 atm, (Running in the x16(x16) lane) and it has a 2nd PCIe x16 slot, but it states x4 electrical.

I am not too fussed either way (from what I can gather the performance hit is only 5% or less), but just wondering :)

If it states 4X electrical than it will only be 4x. The board is not WIRED to handle 8x or 16x on the second slot.

the reason they still put a 16x slot in, is because, the pieces of plastic are cheap, and it saves them money not having to inventory too many different items. (plus allows you to run a second video card, even at reduced BW))