Graphics instability with stable(?) CPU overclock?

[ToxicJr]

Hello all, I'm new to the forum and wondering if anyone has run into this before...

 

OS:        Windows 7 Pro 64 bit

MB:        Asus Maximus VI Extreme Z87

CPU:      I7 4770K

MEM:     Dominator Platinum 2666 4 x 4G

SSD:      Samsung 840 Pro 256G x 2 RAID 0

Cooling: Corsair H100

GPU:      EVGA GTX670 x 2 SLI

PSU:      Enermax Galaxy 1000W (2009 vintage)

KBD:      Saitek Cyborg V7

Sound: SoundBlaster Z 5.1

Mouse:  Mad Catz RAT 7

Monitor: Sharp Aquos 46" 120 Hz LED TV

 

So the above is my new build, graduating from my old 790i Ultra MB that just REFUSED to die, everything good with no OC and 3D Mark11 score of 14991 stock. I thought I'd take advantage of Asus's AI Suite III automatic overclocking to give me a starting point to work from, and gave 4.6 GHz a shot. Booted up, no issues, ran Aida64 for a couple hours, no problems or throttling but CPU temps were a little warm at 70 - 75C peaks. I'm thinking I should be able to tweak things and bring that down some, but normal gaming and usage shouldn't generate temps anywhere near that. As I said, I was just looking for a starting point and I was encouraged with what I saw. Just for grins, I ran 3D Mark 11 again to see what kind of numbers I'd get at 4.6 GHz. All hell broke loose. Frame rates were all over the place during the run, started off at 120+ FPS and immediately dropped down to 45, then 30, then 9, back up to 20, 35, 19 and so on, totally erratic. At stock I was getting from 60 to 70 FPS on the low side and 110 to 120 on the high side in the first benchmark with a nice, smooth transition in between. Dropped it down to 4.4 GHz OC, same thing, set it back to stock and then had no issues again. My suspicion is that my old PSU shown in bold above may have finally met it's match or is not stable enough for the Haswell with the GPUs loaded, so I'm looking for comments in that regard before I go drop $325 for a Corsair AX1200i PSU. Any suggestions as to the best way to verify whether the problem is PSU related? Maybe remove the second GPU for a test and see if the graphics are stable at that point? Thanks in advance for any suggestions or if anyone else has run into a similar situation that did turn out to be PSU related.

Cheers,

Neil

[Godlygamer23]

Two 670s will not bring a 1,000 watt PSU to its figurative knees.

[Godlygamer23]

Are you using Adaptive V-sync? How did you go about your overclock?

[ToxicJr]

Hi Godly, thanks for the reply! - just did the auto OC using Asus's AI Suite III utility. You set the target CPU speed and it automatically adjusts everything for you, and as I mentioned, is a good way to get a starting point for tweaking the OC. The thing that throws me was Aida64 ran good for 2 hours, no problems... until I loaded the GPUs with 3D Mark11. Edit: Linus made a big to do about the need for stable power for the Haswell in his Youtube video demonstrating OCing the Maximus/4770K so that's what has me concerned.

[Godlygamer23]

Does AIDA64 offer stressing your system bus?

[ToxicJr]

The stress test I ran tests CPU, FPU, cache and memory, I don't see an option to stress the bus. Let me check to see if there are additional benchmarks for the system bus.

[Godlygamer23]

Well, that's what I meant. The RAM. Try putting your overclock to 4GHz.

[ToxicJr]

No, don't see anything in that regard. I'm new to Aida64, had always used Prime95 in the past, but they don't recommend that with the Haswell processors. When you say system bus, are you referring to the front side bus?

[ToxicJr]

OK, our posts crossed paths - the stock boost speed on the 4770K is already 3.9GHz however. I'll play with it some more tomorrow night... well, I guess it's already tomorrow. 3:38am where I am. LOL! I better hit the hay for tonight, but thank you so much for responding. Much appreciated.

[Godlygamer23]

Still, that's only boost. Try leaving it at 4GHz and running 3DMark 11 again.

[ToxicJr]

OK, I'll give that a shot tomorrow night and report the result.

[ToxicJr]

OK, I found the problem. When I was taking a closer look at my GTX 670s in EVGA Precision, I noticed that the GPU clocks were not running at the rated speed, even with no OC. When I put this build together, I noticed that the Asus provided SLI bridge didn't fit tight, felt kinda loose, but I figured ok, they ought to know how to make a bridge for their own motherboard, right? Wrong... swapped out that bridge with one that fit good and snug, and voila! Cards were running at rated speeds and no problems running 3DMark11 with a basic, untweaked 4.6 GHz CPU OC. Matter of fact, the 3DMark11 score went from 14991 stock to 16170 with the OC. I'd have thought I would have gotten a little more out of it after getting the SLI bridge problem sorted, but the graphics instability problem is solved at least. Now I can get to work fine tuning this OC! Thanks so much for the responses:-)<br />Cheers!<br />Neil

[sof006]

OK, I found the problem. When I was taking a closer look at my GTX 670s in EVGA Precision, I noticed that the GPU clocks were not running at the rated speed, even with no OC. When I put this build together, I noticed that the Asus provided SLI bridge didn't fit tight, felt kinda loose, but I figured ok, they ought to know how to make a bridge for their own motherboard, right? Wrong... swapped out that bridge with one that fit good and snug, and voila! Cards were running at rated speeds and no problems running 3DMark11 with a basic, untweaked 4.6 GHz CPU OC. Matter of fact, the 3DMark11 score went from 14991 stock to 16170 with the OC. I'd have thought I would have gotten a little more out of it after getting the SLI bridge problem sorted, but the graphics instability problem is solved at least. Now I can get to work fine tuning this OC! Thanks so much for the responses:-)<br />Cheers!<br />Neil

Its funny how the slightest little thing can cause such a big problem. Glad you have it fixed.

[ToxicJr]

 

Its funny how the slightest little thing can cause such a big problem. Glad you have it fixed.

 

Ain't that the truth!? With all this technology packed into such a tiny space, sometimes it amazes me that today's PCs even run at all! Sure doesn't take much to gum up the works...

[Godlygamer23]

Good the issue is gone.