Topic: SOLVED - Two 6990s different results. (1BTC Reward) (Read 2121 times)

My Bitcoin address is in my sig  

Glad you got it to work, every M/hash is truly vital. HAPPY MINING!!

LOL, that must had been quite a WTF moment

It's the Physical switch. It overclocks the core to 880.

Lol nice pic!

Was that the motherboard BIOS? and a digital or physical switch?  Cuz I know there's something called GPU-boost or something like that on some ASUS motherboards and I know MSI also has a physical OC switch which I thought was a really, really, really stupid idea cuz of stories like this 

For the unhelpful help worth approx 0.000000004 rounded (lol 9 digits...get it?) my address is:

1KM4x4mXsaTHRX2D7pKXvris4FZHVZbeaB

I didn't get the addresses of my 2 most trusted assistants on this matter though:

Oh My God! I Solved it! BIOS switch at "overclocked" position 1 and worked perfectly!

Thanks guys for supporting!

Please give your bitcoin address so I can reward all of you who tried helping me 

Maybe you use diffrent Desktop resuoltion on the 2 pcs?

A very high resulution needs more power from your graphic card?

best regards,
XuS

Are you using the same CPUs and more importantly the same motherboard model?
If it has more PCI-e slots try the slow card in other slots too.

Yes I did a couple of times.

The PSU used shouldn't be an issue. Have you restarted the first machine since discovering this?

The crossfire is enabled by default for the 6990 GPUs. Performance on my second card is nice but the first one is minimal since clock settings are same / similar.


fyi, first card uses 750W PSU, second uses 650W PSU.

Crossfire has been known to slow down cards on windows.

@Desolator: I ran GPU-Z and found out the first card has crossfire disabled.  image:

https://i.imgur.com/Yg2pq.jpg

https://i.imgur.com/HdkC2.jpg


I remembered installing catalyst control center on the first card but not second.  Can ATI CCC enable Crossfire? hmm.. best to try it.


EDIT: The first card actually has crossfire enabled when I selected the other GPU. BIOS version same for both.

This seems a lot simpler than everyone is making it.  First of all, same driver, right?  Probably  The real answer is, just because you got 2 cards at the same time from the same vendor doesn't mean they shipped with the same BIOS version.  Yes, video cards have BIOS ROMS too, ppl.

1. Back up both BIOSes on each card to 2 separate files and name them with -slow and -fast at the end so you know which is which.

2. Update both of those cards to the latest version, not just the slowest one, and you should see more consistent results.

3. test the results

4. if they're both fast, yay.  If they're both slow, load both cards with the (at that point) older and faster BIOS version which should be the one you saved called something like "6990BIOS-backup-fast" and load that onto both cards.

If that doesn't help, the 2nd card is most likely receiving less voltage from the power supply.  Test it by swapping the supplemental power cables going to the cards with each other and see if the MH/s swap as well.

I think setting the clock speed means you're setting a target, not magically setting what reality is occurring in the card's GPU.  That'd be cool if they did that though cuz then you could set it at ANYTHING lol.  Either way, I know for a fact that a lot of overclocking utilities don't say what the clock speed is in realtime, they just list what the max/target speed is set at.  If the voltage has dips or is constantly a bit low, the card will downclock itself.  I think that shows up in the realtime meter shown in the nice free utility called GPU-Z as of at least version 0.5.4.  Watch the clocks on both and see if one keeps taking a dive or is operating slower than the OC setting you set it at.

If all that leaves you with no fix, turn the memory speed up slightly past 840 in tiny steps on the slower card.  I've heard reports of identical cards slowing down (but not THAT much!) if they don't operate at a specific random speed.  Like someone said they have two 5830's and one prefers 325MHz and one prefers 375MHz and both perform poorly outside of that exact number.

Yes both are using Windows 7 64bit, 2GB RAM each PC

Look at the 1st picture, and you will see, that the slower Mh/s card are running at 99%

@Mezzan: Both PCs are running the same OS?

http://www.geeks3d.com/20110616/gpu-shark-0-5-1-released/


trying using this on both cards and see if they are both GPU usages are at 99%.

Update us when you can. Like I said, try TRIXX if it allows you, I think it may solve your problem

Good idea but that's what I'm afraid of. I'm worried if i swap the cards the 800MHash/s card will not get that speed anymore even if i put it back but heck, I'll give it a try tomorrow since it's at my data center. I'll update on anything I find tomorrow.

I'll try with TRIXX as well.

What happens if you swap the cards? Do the numbers follow the card or the motherboard?

Have you tried doing it with TRIXX?