Question gtx 1070 not recognized on the PCIe 16x slot

[biliev1985]

I'm trying to run 2x gtx 1070 on an old Asus M4A87TD/USB3 for mining. I get the one using a PCIE Riser 1X to 16X working, but the one on the original PCIe 16x does not get recognized. When running only with it, i get the 1 long and 3 quick beeps at startup.... At the same time with an old Radeon HD 6770 series the PC boots up just fine - so its not a faulty slot.

Any ideas?

 

[biliev1985]

After some digging, I've tried the following with no success:

• bios flash to latest version - no success
• bigger PSU - no change
• bios reset(removed battery) - after initial start - I can see the bios using the gtx1070. yet after setting it up I get again the 1 long and 3 quick beeps

Doesn't seem to be hardware issue...but I have no idea what else to try.