Having performance issues in games with my new build

[mire]

So I just finished putting together my new PC. I'm using the GTX 760 from my old machine while I wait for Nvidia's next generation to come out (or for my Rift to show up and the need to play VR games to overwhelm my common sense and force me into buying a 980 ti). The new specs:

CPU: i7 6700k
Mobo: Asus Maximus VIII Hero
RAM: 32 GB Corsair Vengeance LPX 3200 MHz
PSU: Corsair HX 1000i
OS: Windows 10 Pro 64-bit
System Drive: Samsung 850 Evo 500 GB

So everything seems to be running smoothly, internal temperatures are all good, idling around 30 C. I've got my RAM running at 3200 MHz with the correct timings, CPU and GPU are both running at their advertised speeds, the PCIe port the video card is on reports that it's running at x16, etc. But when I run any game with 3D graphics, I'm seeing my framerates drop from a smooth 50-60 down to 25-40, with micro stutters, after the first couple of minutes.

Now, I know what you're thinking - this is clearly an overheating issue. But I've been watching my temperatures while this happens, and nothing's getting particularly hot. The GPU makes it up to about 70 C, but then holds steady there, and from what I've read it should be able to handle temps up to about 120 before having issues. The CPU is maxing out in the low 50s at worst. And none of the other sensors on my motherboard are any higher. I'm also not seeing any other stability or performance issues even while the game is running, as far as I can tell.

This problem was much worse when I first started the machine up, but turning on all the power management options that had defaulted to disabled in my BIOS helped a lot.

I've tried re-seating the video card, checked all the power cables, but nothing's fixed it so far.

I've also tried the bcdedit /set disabledynamictick and useplatformclock thing that some people have said will fix micro stuttering, but it doesn't seem to have helped.

I'd very much appreciate any new ideas people might have - I'm at a loss at the moment.

Thanks!

 

[TheroXx]

All I can think of is that its the 760, does it still drop frames massively at lowest settings?

 

[mire]

Yep, dropping the quality doesn't help much.

New development: I'm running with the case open and not seeing the slowdown, which now has me thinking it must be a heat issue after all. Is 70 C hot for a video card?

 

[TheroXx]

Okay well atleast you mightve found the problem have you got much budget to work on cooling and airflow? If not then keeping the case open may be the best you can do for now

 

[mire]

OK so I'm an idiot It was 100% the video card overheating. One of the front intake fans was blocked by its own power cable, and my top exhaust fans were flipped the wrong way (no arrows so I had to guess). Fixing those two issues seems to have stabilized the video card's heat issue.

The weird thing is, even with those problems, there should have been much better airflow in this case than my old one, because I don't have power cables clogging things up (they're routed much better, around the back of the motherboard mounting).

And weird thing #2: I never saw the card go over 70 degrees when this was happening, but the Internet assures me it should be totally fine even running at 90, and shouldn't start having issues until it's well over 100. So I must have a badly calibrated temperature sensor on the card as well.

My best guess as to what's going on is that the card is hitting higher levels of utilization now that it's not bottlenecked by the CPU, which is why I'm seeing problems now that I wasn't before. On the bright side, EVGA has started an RMA for me, so I'm going to go ahead and swap it out while it's still under warranty, just in case the repeated overheating I've put it through in the past through days caused any long term damage.

Thanks for the suggestions