DISCLAIMER: This is not an official, EVGA approved fix/BIOS. Please use at your own risk! Flashing your card's BIOS always has a small risk that something might go wrong. Be sure you know what you're doing, especially how you would "unbrick" your card should something go wrong. I can not be held responsible should anything go wrong.

 
After lots of investigation and sharing experiences with others I/we concluded that the "Black Screen, needs PC reset" problem is because of that some cards, among them GTX 970 SC ACX2.0 cannot handle the overall load/power draw. (It's not so much a matter of that an overclock is not stable since those crashes are different, in those cases the driver crashes and the system can recover).
 
I found that the black screen issue can be solved by limiting the maximum voltage the card is using at it's maximum speed.
(In fact, my SC ACX2.0 does 1506 stable, tested, at 1.187V. Since my-2974 GTX ACX 2.0 is a very average card with ASIC quality 70% I have reason to believe that the fix should work for MOST -2974 cards)
 
The 1.187V - as compared to 1.212V or 1.200V (as would be the max voltage with the original bios) draws less power, prevents black screens, reduces temps and throttling.
 
If you have the black screen problem and want to save yourself a RMA, I can help you if you are comfortable flashing BIOS and know how to do this. Of course you would flash your cards bios at your own risk. Don't flash if you would not know how to unbrick your card again should a flash go wrong! And obviously this is only for EVGA GTX 970 SC ACX2.0 -2974 cards!
 
The BIOS here have more advantages:
 
* 1506 overclock without throttling
* Power Target increased to default 196W (from the stock 170W)
* The problem with instability at lower clocks is gone. (NEVER overclock those card's (-2974 models) core clock with Afterburner. Since you cannot add voltage with Afterburner, overclocking the core with Afterburner means that the entire voltage table won't be correct which results in instability at lower clocks). With my BIOS, this problem is solved, the clocks and voltages scale properly.
* No throttling due to "Voltage Limit" since the max. 1.212V which are specified in the BIOS are never used
 
Those BIOS also work great as general BIOS for your card, whether you have the black screen problem or not. As compared to some other modded BIOS out there, boost is not disabled and the card's voltages scale properly.
 
BIOS 1) (Try this first)
1506 clock at 1.200V
https://www.dropbox.com/s...ACX2.0_1.200V.rom?dl=0
 
BIOS 2)
1506 clock at 1.187V (this might only work with cards with very high ASIC, 75%+)
https://www.dropbox.com/s...ACX2.0_1.187V.rom?dl=0
 
If your card has troubles with 1506, here the same with somewhat lower clocks:
 
BIOS 3)
1443 at 1.200V
https://www.dropbox.com/s...ACX2.0_1.200V.rom?dl=0
 
BIOS 4)
1443 at 1.187V
https://www.dropbox.com/s...ACX2.0_1.187V.rom?dl=0
 
I recommend you try BIOS 1 first and if you still have black screens under stress (Heaven Benchmark, Games etc.) try BIOS 2 which uses even less voltage at max clock.
 
Should your card be unstable (driver crashes, artifacts etc.) try the 1443 BIOSes with somewhat lower clock. Here too try the 1.200V first, if it black screens use the 1.187V BIOS. (I found the best test for black screens is Heaven Benchmark at Ultra/Extreme and have it run for at least an hour or longer).
 
Please share whether your black screen problems are solved with those BIOS!
 
 
** UPDATE May, 21 **
 
Updated BIOS with "proper" down-clocking voltage table. Ie. should the card ever need to throttle in the upper clock ranges it does now correctly decrease voltages.
 
** UPDATE May, 27 **
 
While the above and my workaround with those BIOS still works, I am at a point that I am rather certain that the black screens are from overheating components (voltage regulators) on those cards. There is an undeniable relationship between fan speed, temperatures, load on the card and the likelihood for black screens.
 
My BIOS help since less voltage means less power draw/load and lower temps, therefore they can help to prevent the black screens crashes. HOWEVER it is important that you keep your fan running as high as you can tolerate it. I found the default fan settings in the original bios NOT sufficient. You need to get Afterburner or PrecisionX and create a custom fan profile where your fans are running 45% or faster at 75C depending how loud you can tolerate. This together with my BIOS is the best way to prevent black screens. Proper cooling of the card is important!!
 
It is also likely that an aftermarket cooler like the Arctic Twin Turbo II with the included heat-sinks for VRMs should prevent the black screens. Here however you would need to find a way to attach the heat sinks of the Twin Turbo II in a way as that you can remove them again (the included thermal glue is permanent!) otherwise you would void your card's warranty.
 
 
***
Guide: How to flash your card's BIOS:
 
Please see Easy NVFlash Guide with Pictures for GTX 970/980"
at http://www.overclock.net/...ctures-for-gtx-970-980
 
***
 
Always Backup Your Original BIOS

 
You need your original, unaltered BIOS flashed back on the card in case you would ever need to send it in for RMA or something would go wrong and you want to flash your card with the original BIOS.
 
This is how you backup your card's BIOS: Get yourself GPUZ. Disable your card in Windows device manager. In GPUZ, below the Nvidia symbol is an arrow symbol. Click on the arrow. It will ask you to save your card's BIOS to a file. Save this to your computer.
 
There is also a good collection of VGA Bios for various cards and vendors on TechpowerUp's VGA Bios Database.
 
 
DISCLAIMER: This is not an official, EVGA approved fix/BIOS. Please use at your own risk! Flashing your card's BIOS always has a small risk that something might go wrong. Be sure you know what you're doing, especially how you would "unbrick" your card should something go wrong. I can not be held responsible should anything go wrong.
 

I do hope you have a least reported this problem on NVIDIA's Support Site as well.
 
What are the Card Owners recovery options if they brick their card installing the above firmware on their Cards?

bcavnaugh
I do hope you have a least reported this problem on NVIDIA's Support Site as well.

Nvidia is making the GPUs, those are fine. In fact, the chips itself clock very well.
The black screens (IMHO) are a problem of particular card manufacturers and "poor" components pushed to the edge and sometimes even at stock. We have a theory that the black screens are actually over-current protection of the voltage regulators kicking in. So this is solely an issue that concerns some card makers, not Nvidia. My $0.02.

bcavnaugh
What are the Card Owners recovery options if they brick their card?

Boot up with another card or your internal IGPU (if you have an i7 or so CPU). With bricked card in one slot of your board.
Use NVflash (Nvidia's flashing tool) and flash the bricked card back to original BIOS. There are other ways, like "blind flashing" from a bootable CD or USB. You would have to read up on the options for NVFlash , say, how to specify the correct slot to flash etc. or how to make a bootable USB stick that "auto flashes" a bricked card if you don't have a second, working card.

flexy123

bcavnaugh
What are the Card Owners recovery options if they brick their card?

Boot up with another card or your internal IGPU (if you have an i7 or so CPU). With bricked card in one slot of your board.
Use NVflash (Nvidia's flashing tool) and flash the bricked card back to original BIOS. There are other ways, like "blind flashing" from a bootable CD or USB. You would have to read up on the options for NVFlash , say, how to specify the correct slot to flash etc. or how to make a bootable USB stick that "auto flashes" a bricked card if you don't have a second, working card.

"What are the Card Owners recovery options if they brick their card installing the above firmware on their Cards?"
And if they do not have a second card or an internal IGPU?

Just saying you should cover yourself is all.
You need to post some kind of warning and also let users know that this is not an approved firmware.

bcavnaugh
Just saying you should cover yourself is all.
You need to post some kind of warning and also let users know that this is not an approved firmware.

Done! This is the official EVGA forum and you have a point! I added a disclaimer so people don't get a wrong impression this being an "official fix" or something.

Here is my feedback:
 
I created this topic: forums.evga.com/So-Precision-X-970-Overvolt-works-or-not-m2337796.aspx
 
Before @flexy123 solution, i tried everything possible as is on my topic. So far i can tell the solution number 4 solved my problems! No more Black Screen until now, many, many thanks, flexy.
 
Tried all versions, all before number 4 i got blackscreen. And i was thinking that more voltage would solve my problem...it was just the contrary lol.
 
It IS (MUCH)  worth try for everyone that is having black screen on SC ACX 2.0 2974. Worked like a charm for me!
 
I´m only PISSED because a USER had to figure out what the heck was going on... where was EVGA support until now? It´s a shame...next time i will go GIGABYTE G1 instead...
 
One more time, thanks flexy!
 
 

flexy123
 
 
Nvidia is making the GPUs, those are fine. In fact, the chips itself clock very well.
The black screens (IMHO) are a problem of particular card manufacturers and "poor" components pushed to the edge and sometimes even at stock. We have a theory that the black screens are actually over-current protection of the voltage regulators kicking in. So this is solely an issue that concerns some card makers, not Nvidia. My $0.02.

Yes, I agree. A few years ago I endured 4 RMA's for defective evga cards (all black screened). I was so frustrated I bought an Asus card and never looked back. Sorry EVGA. Your customer service, however, is top notch.

Hello,
 
Thank you! I want to add some more findings I made in the meantime.
 
I am currently *strongly* believing that it is an heat-issue related to the voltage regulators on those cards.
 
I found that a higher fan speed (in my case 47%) almost always can prevent black screens. My assumption is that higher fan speed simply cools the voltage regulators better and that the stock fan curve is simply not enough. (This is why I recommend to use a tool like MSI Afterburner).
 
It's is not so much an issue about the GPU temps (the temp which Afterburner shows), but the GPU temp can give an indication about the temps of the voltage regulators. (Aka: When the GPU is getting to 77C or higher one can assume that VRMs are also getting very hot)
 
From this one could also conclude that the VRM overheating and black screen issue would be solved by
A) either getting MSI Afterburner and turn up fan (it depends how loud you can handle it, my tolerance is 47%)
or
B) install a aftermarket cooler like the Arctic Twin Turbo II which comes with heatsinks for RAMs, VRMs etc. as well and has a FAR superior cooling performance than the stock cooler.
 
My BIOS therefore helps not because it "uses less power" (as I assumed previously) but simply because using less power (like 1.187V in my case as compared to 1.200V etc.) also creates less heat. There is definitely a relationship between fan speed (temps) and the occurrence of black screens.
 
TLDR: If you're (still) having black screens, increase your fan speed! Use MSI Afterburner and make a "steeper" custom fan curve. The default fan curve of those cards is NOT sufficient to cool the VRMs, especially under stress and especially if you overclock. I can get a black screen using default fan speed in just two runs of Heaven Benchmark...but NOT with a more aggressive fan curve.