What kind of issues do you have?
Well, it started out with my GTX 980. I bought a reference Gigabyte 980 and while gaming I noticed this burning smell all the time. I thought it was just "burning in" because my 290x did that for a week or so. Well, almost a month goes by and this burning smell persists then one night on BF4 I get a series of TDRs followed by some heavier burning smell. Desktop started freezing too after reboot. Something blew or was running super hot inside the card. Since it is contained with the blower and that backplate, I didn't know what it was unless I disassembled it. So I just RMA'd it. This was the start of the issues. I go out to best buy and purchase 2x 240gb PNY Optima SSDs for RAID 0, put them in the machine and the whole system doesn't POST. Cleared CMOS, then it POSTed. Setup RAID and install windows, all the sudden I get repetitive blue screens of IRQL_NOT_LESS_OR EQUAL. I haven't seen that since XP days. Tested the drives in my other rig, no problems there then once I get them back in my X99 rig, all the sudden my 290 starts with the TDRs on the desktop on a fresh install. I restarted and ran 2 hours of Valley benchmark and it didn't crash once and ran very cool. Next day system decided it didn't want to POST again. I got frustrated and ordered a Gigabyte X99-UD4, a new case (Phanteks Enthoo Pro), new Power Supply (Rosewill HIVE 850 Modular).
Sorry for the wall of text but you did ask I really think it was the power supply because I found a bad lead on the ATX 24PIN connection on my Hale82 850w. It served me for 3 years, I can't complain too much.