EX58-UD5 with 5870 Crossfire

Dunners

Dunners

Dunners

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Hi all

Bought a complete system from OCUK with an EX58-UD5 motherboard and two 5870's in crossfire. I've got one card coming up as 8 speed only.

To fix this I have tried (so far):

Making sure the cards are in the right slots
Swapping the cards
Flashing the MB bios and updating to latest (F9 bios)
Taking the overclock compeltely off
Putting a new overclock profile on


The issue remains. The second card is showing as 8X in the CCC and in GPU-Z

Has anyone ever had this issue? If so any ideas!?

Thanks in advance for any advice!
 
Have you got any other PCI cards installed in the PCI-e x8 lane below the 2 x16 slots (i.e. the PCI-e slot nearest the bottom of the mobo). A sound card/Wireless card etc?

If you have then this will be why. The 2nd x16 PCI-e lane shares bandwidth with this x8 lane and if both are populated then then x16 lane will operate at x8 speed.
 
I found there are only 2 PCI express slots at 16* the other last one is 8* , so my first 2 GPU's had to be sandwiched together on the 1st and 2nd gpu slots not good for air flow, as I wanted slot 1 and 3 for the gpus could not due to the third slot is 8* and me wanting 2 gpus @ 16* PCI express speed.
 
The difference between 8x and 16x when corssfireing is nothing! You lose 2% fps, so not even noticeable. You will have no trouble using the 3rd pci e, but would have to get the correct sized crossfire ribbon.
 
.:SAmSuNG:. said:
Thats really odd. If you stick one card in the 2nd slot by itself will you get full x16 then?
Click to expand...

Thats one thing I havent tried yet. I guess if one card does run at x16 on its own in that slot that would eliminate the possibility of my bottom x16 lane being faulty. l'll give that a crack and let you know.

I realise the differnence is very small but its annoying that it doesnt work
 
You lose more like 5-10%, actually, and much, much more on the more important minimum FPS. I've seen benches showing minimum FPS as much as 33% higher on full 16x + 16x compared to 8x + 8x, and that was with GTX 285s; 5870s would be even more choked.

Payload exceeding bandwidth = lag, and that will be noticeable.
 
I've tried my EX58-Extreme in x16x16 vs x16x8 using with crossfire 5870 and a 9600GT in the third slot and it makes sod all difference.
 
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OK ive got only one card in now and its telling me that its only x8 speed. Its definitely in a x16 slot and there are no other slots poulated with anything else.
 
Try each card individually in each slot to see if you can eliminate either a card or PCI-e lane error.

If, for example, you find that both cards read x16 speeds in lane 1 but x8 in lane 2 you can almost be sure that it is PCI-e lane related. If however one of the cards reads x8 speeds in both PCI-e lanes and the other card reports x16 then you can safely say that it is a card issue. A bit of work putting the cards in and taking them out is required but I think it is necessary to try and identify the fault.
 
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Try a different bios perhaps?
I'm running F7 with no issues and getting 16x16x.

There's also and option in the bios to set the lane speed for PCI-e, make sure its set to 16x obviously.
 
Yeah flashed the bios and updgraded to latest version as one of the first attempts to fix this. Also tried with and without the overclock profile.

Where in the bios do I see PCI-e lane speed? I've not seen that in there..
 
Are you sure you are using the correct slots?

Sorry if i'm teaching my grandmother to suck eggs but it can be the simplest of errors sometimes, and needs someone to state the B******g obvoius.

I have the EX58-UD5 motherboard, 2 x 5870's and a GTX280

PCI-e 1 is the slot nearest the CPU which is 16x speed

PCI-e 2 is the next PCI-e down which is 16x speed UNLESS you have something plugged into the 3rd PCI-e then it slows to 8x speed

PCI-e 1 is the slot nearest the bottom of the board which is always 8x speed.

I have the 2 5870's in slots 1 & 2 and the GTX280 in slot 3 with slots 2 & 3 running at 8x speed.

I barely noticed a drop in FPS at all, certanly none to worry about.

If you have plugged them in right, sounds to me like a faulty board. RMA it.
 
Yeah all plugged in right - was hoping it was something other than a faulty board. Its part of a compete system whch has been back once already due to dodgy graphics cards.

Really don't want to RMA it!!

I'm interested in this PCI-e speed setting in BIOS someone mentioned!? Could it be that its set wrong in BIOS?
 
There is nothing in the BIOS (any version) which will allow you to alter the PCI-e lane's speed between x8 and x16 - CreAtiv3 is wrong on this. The board manages it automatically because there are only really 2 options - PCIEX16_1 & PCIEX16_2 running at 16x 16x unless a third PCI-e device is installed in PCIEX8_1 - in this case they run at x16 x8 x8.

There are a couple of settings (PCI-e related) that you could try changing in the BIOS - they are complete long shots but I'm guessing you are willing to try anything? Try changing the Init Display First option (Advanced BIOS Features) to something different - there are a few options so go through them systematically using each card in different slots both individually and together in Crossfire (yawn, I know). Also try changing the PCI Express Frequency (Mhz) setting (Advanced Clock Control) to something different - e.g. 101. However, note what it was set to before though just incase you need to change back - it should be 100 or Auto (which is 100).

Also, just to check, are the 5870s both the same brand e.g. both Sapphire or both XFX? Again, probably not the problem but the mobo's user guide does specifically say to use the same brand, so potentially an issue if they are different.

One more thing, when you have got time between installing/reinstalling cards could you check, with both cards installed, whether GPU-Z reports any other obvious differences between them (aside from serial numbers etc.).
 
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