problem with starting system up with 3x r9 280x plugged

[staypoh]

hey there,

after 2 days of battling with them i run out of options. Are there any known issues with z87 chipset and multiple gpu's?

problem is following: i have 2 motherboards 1) asus z87a 2) asus sabertooth z87 and 3x r9 280x. When 3 of them are plugged in, on powering system on, everything will power up, all the fans will start spinning, even ethernet port will start blinking green/yellow as if it is working, but nothing is being fed to the screen, even bios does not load, just a black screen. each card works fine separately, 2 card work together, 3 - do not. Both motherboards have 3x pcie 16x, both boards support quad gpu's.

most interesting part is in both cases with both boards, CPU error led indicator is lit up red on the board when i try to start with 3 cards in.

rest of the system:
cpu: pentium g3220
ram: 1x4gb ddr3 1333
ssd: samsung 840 128gb
psu: modular 1050w
cards: 2x sapphire dual-x r9 280x + 1x msi gaming oc r9 280x

please advice if any ideas, thank you guys!

 

[AgedIdiot]

Am not running myself but based upon a quick google - can your board run tri-fire? Does it have the latest bios? Have you set up in the right order? (only reason for mentioning this was a thread I read on another forum where mention was made of trying to run 7970/7950/7970 and it would only work in this order - I appreciate that you are running 3 x 280x but as one is clocked a little differently it might be relavent ) Do you have to adjust any switches or settings for the motherboard? And you do have correct crossfire connectors in the right order?

I am sorry that all I cannot advise as to solution but all of the above have been mentioned as reasons why it might not work.

Good luck

 

[staypoh]

Am not running myself but based upon a quick google - can your board run tri-fire? Does it have the latest bios? Have you set up in the right order? (only reason for mentioning this was a thread I read on another forum where mention was made of trying to run 7970/7950/7970 and it would only work in this order - I appreciate that you are running 3 x 280x but as one is clocked a little differently it might be relavent ) Do you have to adjust any switches or settings for the motherboard? And you do have correct crossfire connectors in the right order?

I am sorry that all I cannot advise as to solution but all of the above have been mentioned as reasons why it might not work.

Good luck

thank you! switching to gen2 and mixing cards order around helped (not sure which one, because did them at the same time, and i am pretty sure i did try gen2 before, as well as clocks on all 3 cards are identical by default 1020/1500) but something definitely worked, and now system starts 9/10 times.
p.s. cards are not running in crossfire, they run as 3 separate instances

i do have another problem though, but it would be offtopic here, so i will seek help in another place. Thank you once again!