Dual 470 OC Problems - Need Advice

[homegun]

The system I just built:
i7-2600K
ASUS P8P67 PRO MB (Soon to be replaced by a new glitch-free version?)
8 GB Corsair Vengence RAM
XFX XPS-850W Power Supply
HAF 922 Case
2 X Galaxy GTX 470 1280MB Video Cards
Scythe Mugen CPU cooler
2 X Samsung F4 1TB HD
1 X ASUS DVD-RW drive
Windows 7 64 Bit Home Premium

I hooked it all up, loaded the OS, and it booted first time.

Then I OC'd the processor to 4.5GHz and it's stable as a rock.

I set the VCs in SLI mode, and get tremendous FPS!

Now I am trying to OC the cards, but all of my attempts have failed. I have tried the Galax XtremeTuner and the MSI Afterburner software. I can only manage mild OC (like going from 625MHz to 675MHz) before I either get artifacts, freezes or total video death and have to reboot.

I'm just wondering what might be the problem - the cards themselves, motherboard, or maybe the PSU not capable of driving that much power?

What do you guys think?

Eric

 

[Leaps-from-Shadows]

It's not the mainboard.

It's not the power supply.

That level of overclocking on graphics cards isn't a "mild OC" -- that's actually pretty good. Overclocking a single card is fairly easy, but getting an SLI setup to cooperate enough to do it is more difficult. Not all of them will overclock more than that, and you can't buy a "matched pair" like RAM. One of them is likely holding you back, but unless you're going to remove it there's no point in finding out which.

Just be happy with your totally unnecessary graphics card overclock.

 

[nighthawk4]

i'd try to OC them seperately, and see which one is holding you back, and if it's not the SLI bridge or something else that's holding you back. then when you know how fast you can go, you can put in both and see if it's stable then.

 

[homegun]

i'd try to OC them seperately, and see which one is holding you back, and if it's not the SLI bridge or something else that's holding you back. then when you know how fast you can go, you can put in both and see if it's stable then.

Thanks! I'll give that a try. The setup is stable at the stock speeds. I'll see what I can do with the cards individually first.

It may be "totally unnecessary" but it's fun. :lol:

 

[homegun]

Overclocking cards in SLI is a bitch. Flash the 470's to 480's and they'll both be over 700 core

I just read about that being done for AMD cards. 6850 to 6870 I believe? Can you also do that to the 470? Is there some good information here on the forums or elsewhere that discusses that?

Thanks,

Eric

 

[homegun]

I finally reached stability!

CPU overclocked to 4.5GHz

VC core clock to 700MHz
Shader clock to 1400MHz
Memory clock to 1800MHz
Voltage to 1.080

Ran the setup hard all weekend and it never glitched or resulted in a BSOD. Temperatures got a little scary at times but not too bad. Having a total of eight fans in the box helps.

Rather than using Galaxy's Xtreme Tuner, I ended up using the MSI Afterburner software. For some reason that made a difference.

Just FYI,

Eric

 

[homegun]

Best answer selected by homegun.