[nightfox]

Need help and opinion guys.... I am trying to find out an optimal or maximum OC I can do for benchmarking, for gaming, and so on and so forth..

Eventhough I have same brand, same model GPU's, they are not OC limits identical.

My 1st card can bench at max OC of 1200 / 1585. My 2nd Card can do benching at Max OC of 1125 / 1500 ( This is of course done individually).

But when I crossfired them and set the Max OC they can bench, I simply cannot do benching with these cards...

I can do benching of course but settings of both cards (doesnt seem to bench at different settings) is 1080 / 1480 only.

Is it supposed to be like this?

I am back at 13.4 drivers now as 13.8 crashing a lot than 13.4.

Specs are in my sig Rig.

Thanks

 

[sinnedone]

On my system the crossfire max overclock is less than even the lowest card overclock. I am 15mhz lower than the lowest overclocking card to get it stable. Unfortunately I have no idea about why this is though.

 

[nightfox]

Quote:

Originally Posted by sinnedone

On my system the crossfire max overclock is less than even the lowest card overclock. I am 15mhz lower than the lowest overclocking card to get it stable. Unfortunately I have no idea about why this is though.

yes exactly. same with me although its like 30mhz for me both core and memory is like 50 or something...

well ok maybe because of the pci lane? for example mine has x16 single but dual would be x8 + x8.. that could be the reason why. ok I thought i was the only one experiencing that.

 

[NewAtOCing]

I would like an answer for this as well.

 

[Lionheart1980]

Quote:

Originally Posted by NewAtOCing

I would like an answer for this as well.

I as well had experineced this in the past, i tried to test this theory by upgrading my mobo which has two x16 lane pcie and it works better. Dual x16 gives ya more bandwith per lane than x8 for sure. Look it up. Bear in mind, ivy cpu with 8x lane pci enabled is the same as sandy cpu with 16x lane pci... if u have CF on ivy with dual x8 pci lane is the same as CF on sandy with dual x16 pci lane.

You will get a boost of power into your gpu if u using sandy cpu on dual x8 pci lane mobo to ivy cpu on dual x8 pci lane mobo cuz it act like x16 pci lane on sandy cpu... remember pci 2.0 to pci 3.0 (double your pci bandwith)

 

[Bruennis]

You'll be limited by your second card. I have a 7950 crossfire setup. Top card can do 1220/1540 and bottom can do 1180c/1600m. Crossfired, I can run 'em as high as 1170-1180c/1540m (Depending on benchmark). For gaming, I run 'em at 1150c/1500m @ stock voltage.

 

[nightfox]

Quote:

Originally Posted by Lionheart1980

I as well had experineced this in the past, i tried to test this theory by upgrading my mobo which has two x16 lane pcie and it works better. Dual x16 gives ya more bandwith per lane than x8 for sure. Look it up. Bear in mind, ivy cpu with 8x lane pci enabled is the same as sandy cpu with 16x lane pci... if u have CF on ivy with dual x8 pci lane is the same as CF on sandy with dual x16 pci lane.

You will get a boost of power into your gpu if u using sandy cpu on dual x8 pci lane mobo to ivy cpu on dual x8 pci lane mobo cuz it act like x16 pci lane on sandy cpu... remember pci 2.0 to pci 3.0 (double your pci bandwith)

thanks for input. makes sense. but isnt it when you have sandy cpu, your gpu's will run at pci 2 x 16 (dual). whereas in ivy, they will run at pci e x 8 (dual) which in theory, they will run same? I was thinking of upgrading my mobo as well to gigabyte z77x up7, or asus maximum v extreme cause they are supporting pci e 3 x 16 using one plex chip.
Quote:

Originally Posted by Bruennis

You'll be limited by your second card. I have a 7950 crossfire setup. Top card can do 1220/1540 and bottom can do 1180c/1600m. Crossfired, I can run 'em as high as 1170-1180c/1540m (Depending on benchmark). For gaming, I run 'em at 1150c/1500m @ stock voltage.

this was my question. it seems they are limited by slower card... but does it supposed to be like that? i wonder.... and crossfired setup supposed to run same clock? is there a way to oc them individually, by their own max speed...

i have some interesting thoughts actually as ive tried windows 8.1 with amd 8.1 preview driver. They actually can run at their own speed... ive tried 3dmark 11 and scored higher as well.... well not so muc h higher but ive hit 15k mark on 3dmark 11.

 

[Lionheart1980]

Quote:

Originally Posted by nightfox

thanks for input. makes sense. but isnt it when you have sandy cpu, your gpu's will run at pci 2 x 16 (dual). whereas in ivy, they will run at pci e x 8 (dual) which in theory, they will run same? I was thinking of upgrading my mobo as well to gigabyte z77x up7, or asus maximum v extreme cause they are supporting pci e 3 x 16 using one plex chip.

If you use an z77 up7 which has 3.0 pci-e, and backward able to 2.0 as well... u will still get x16 lane no matter wat cpu u use in single or dual x16 (only if u have mobo which have dual x16 like i have one in my sig (asus p8z77 ws))... but if u use sandy cpu with more than 2 gpus it will be x8 speed like (x16/x8/x8) or (x8/x8/x8/x8)..but with a ivy u will get a speed of x16 instead x8 thanks to 3.0 pci-e since 3.0 is not fully used up yet cuz no cards can produce that much bandwith throu em yet. You know what i'm sayin?

Like futureproofing yourself.. get a z77 mobo with dual x16 is the best long term investment also no bottlenecking any gpus as well

 

[nightfox]

nice thanks.

yeah I was kinda thinking of getting a dual x16 z77 mobo. But cant decide which one. the up7 looks good actually but its a bit pricey still. other than that, I know Asus has one. the Maximus IV extreme?

Any other mobo you would recommend?

wow I look up your mobo its looks good. but same price as up7 (almost)

 

[Lionheart1980]

Quote:

Originally Posted by nightfox

nice thanks.

yeah I was kinda thinking of getting a dual x16 z77 mobo. But cant decide which one. the up7 looks good actually but its a bit pricey still. other than that, I know Asus has one. the Maximus IV extreme?

Any other mobo you would recommend?

wow I look up your mobo its looks good. but same price as up7 (almost)

Thanks

Here is the few i have found still avail at neweggs atm:
ECS Golden Z77H2-AX - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813135304
ASRock Z77 Extreme9 - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157322
ASRock Z77 WS - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157336
ASUS P8Z77 WS - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813131822 (which i have now)
GIGABYTE GA-Z77X-UP7 - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813128569
That what i have found so far on newegg but if you buy pc parts elsewhere you might find some mobo which aren't avail on newegg thou.. let me know if u have store in mind

 

[sinnedone]

Quote:

Originally Posted by Lionheart1980

Thanks

Here is the few i have found still avail at neweggs atm:
ECS Golden Z77H2-AX - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813135304
ASRock Z77 Extreme9 - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157322
ASRock Z77 WS - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813157336
ASUS P8Z77 WS - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813131822 (which i have now)
GIGABYTE GA-Z77X-UP7 - http://www.newegg.ca/Product/Product.aspx?Item=N82E16813128569
That what i have found so far on newegg but if you buy pc parts elsewhere you might find some mobo which aren't avail on newegg thou.. let me know if u have store in mind

game much on your asus? If you do , any input lag with that plx chip?

 

[Lionheart1980]

Quote:

Originally Posted by sinnedone

game much on your asus? If you do , any input lag with that plx chip?

Sure i do game alot and nope i haven't notice any lag input on this system

Hope it helps.

 

[PCSarge]

running crossfire also redirects some of the power from the gpu pwm into the part ofthe card to power the bridge, thus lower overclock capability due to needing to power other components of the cards

 

[nightfox]

oh yes... it does make sense. thanks pcsarge