need help with dvi display using an a10-7870k on a gigabyte a88x MB

yes it has the same MB,same memory, 550w PSU, same case except it's green not red same cool master cpu cooling fan. it's identical to my other unit which runs flawless. when i tear it down to ship the MB back to gigabyte for a swap of the MB i used another spare unit (an old HP dc5850 with a amd 2.6 quad cpu anf 8 gigs of memory) and hook it up dvi and have absolutely no problems with the monitor and computer waking from sleep mode. i am one who believes in never shutting down my computers or letting them sleep because that's where you get burnouts on MB from the power surge from starting up. i've never lost a unit doing this and have 7 units running in my apt. network system and all are going on 8yrs. i only allow the monitors to go into sleep mode. i can live with this unit and monitor never sleeping but the problem still baffles me because it shouldn't be happening. being an old IT tech i can't let go of an unknown problem like this. last night i even pulled the battery to clear the cmos to see if i had possibly messed up a graphic setting in the bios during set up but the problem was still there.

at the moment i am currently having to use the power settings of never sleep for the monitor and computer and using the blank screen saver option.

i'm just completely baffled by this one. like i say i've ruled out all but the APU having a bad GPU in it. i've ordered more thermal grease so that i can swap out the 7870k with the original a 10 5800k trinity APU to see if that fixs it. if so then it has to be in the APU. luckily i bout an insurance policy on the 7870k when i bought it through amazon so if it's bad i can put in a claim and get it replaced or money to buy a different APU but these 7870k are such great chips performance wise for the pprice i'd like to stay with it. though i could live with the 5800k also because it was a great cpu too and was more stable when overclocking. i'd just have to get a crossfire video card for it

as i say i'm at the end of the diagnostic process except swapping APU's but came here to see if anyone had any other possible reasons for the problem that i've overlooked.

i have to say all the negative reviews i've read against Gigabyte warranty's and RMA's are bogus. they couldn't have done a more professional job. i sent the MB in to be repaired but they found nothing and when i put it back in and still had problems they swapped it out no questions asked. i will be a loyal Gigabyte MB user for life when they stand by their product and have customer service of that quality.

AMD on the other hand....i can't even find a tech # to call. i have to summit a form online for the APU warranty.

Well i have a hard time believing it's the APU so i'm going to give your other suggestion a try cause that's the only thing i haven't tried and that's use the original DVI cable and see because right now i'm using a cheap 8ft DVI that may just have a weird quirk in it that the unit doesn't like or pickup the right frequency for the monitor. i have it hooked to the original and it's in test mode. thing is i just bought a low power 250W HDMI video card for the HP dc5850 and installed it and it works hooked up to my tv perfectly. if i had found this low power card 8mths ago i wouldn't have spent the money building the AMD unit. now i have a spare unit that i don't know what to do with if it turns out to be a cable issue on the AMD unit.

thank you Vic. so far so good swapping out the dvi cable. the original Hp cable so far is working. i can't figure out how the other dvi cable worked with every other computer but i guess the AMD 7 series graphics GPU's on the MB and the APU are picky and there was some signal not getting through for it to work. still testing though but if the original cable solves it i am going to have to by a higher end DVI cable if i can find one on newegg. thanks again i never would have thought of it since it has always worked before.

found the problem. the cheap dvi cable i was using was not a dual link dvi cable and didn't support the high resolution amd 7 series graphics which is only compatible with dual link dvi cables with higher frequency bands. just bought a new one for $10 bucks.