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post #12056 of (permalink) Old 03-18-2019, 09:00 AM
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Location: Patras, Greece
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Quote: Originally Posted by mynm View Post
Ok, weird, I have no idea of what can be causing the problem.
Well, I did search around the web when it turned out that my screen was ok and the GPU was causing the problem. The most plausible theory I found was a guy on the AMD forums (I think) that was saying that the DP output of this card is fed by the 0.95V rail and when pushing the core voltage you may get some voltage drop on that rail and cause instability in the display output. That would actually make a lot of sense, considering that the core is the major power hog on these cards. AUX voltage doesn't seem to affect it, or at least not as much. Or it could be BS and I wouldn't know the difference, I dunno. What sucks is that I had to dial my OC down, even if slightly, now that the card needs every last drop of performance it can muster. I could realistically run 1180/1625MHz while on 1080p 60Hz, but now that I use 1440p 144Hz I'm stuck at 1140/1575MHz. Wouldn't make a huge difference, but meh. Oh well...

And, by the way, I got myself a third DP cable. This time, it's a KabelDirekt DP 1.4 cable, so 8K certified and whatever, 5 star reviews all around Amazon.de. Still, same issue. The only thing that changed (but I can't pin it down to the cable change) is that now, when it loses signal it will stay black until I either turn the screen off and on again, or if I switch inputs and go back to DP. That's a minor inconvenience, though, so...

Quote: Originally Posted by mynm View Post
About the wattman memory voltage, if ti is working fot the 390 I don't have a 390 to test, maybe like BradleyW said, it could helpto solve your problem. Because as it is a lower limit to to the core voltage for a memory clock, it can help in transitions from 2D to 3D.

I did some test in the past with the wattman memory voltage for my 380 (now is broken, but not for testing this), and the weird thing about it is that with memory timings mod it can be lowered and not cause any problem. But without it lowering it can cause black screens. Also I have tested to lower it to my new 590, but I get black screens.

I don't know how to do a proper timing mod, I don't have these tecnical skills. But this is the mod I did for my 380 with H5GC4H24AJR memorys (some 390 have the same memoryes, so it coul work for them), for 1500 and 1625 strap, and was working ok with low wattman memory voltages. :

77713320000000006BBD572F40550F0E2892F7060048C50022 559D084C0D14205A8900A000000120100C20246F1E2912

And the values for it that I get with this Vento041 tool are:


The stock timings for the 1500 strap are:

7771332000000000CE516A3D9055111230964909004AE60022 339D08740114206A8900A002003120150F292F94273116

And the values for if are:

Maybe somebody with timings mod skills could test this and say why these timings can help to lower the wattman memory voltage.

As memory timings mod can cause the gpu to brick, is not recomende to do this if you don't have a dual bios gpu or advanced bios flashing skills.

As your 390 performance is excellent nowadays, don't put it in risk.
So let me get this straight. That "memory voltage" is actually how soon the GPU will ramp up depending on the voltage? So, if I'm overclocking, lower would actually be better? I'm a bit confused, sorry.

Well, I wouldn't call the 390x's performance excellent in 2019. It's on par with cards like the 580 and 1060 but can't overclock well and consume, like, all the power. I've seen my card do north of 340W, easy. That was overclocked balls to the wall, but still, damn. So yeah, I would love to see some more squeezed out of my card until I can get a new one, but it not having dual BIOS and me not having experience with BIOS modding kind of kills it for me.

Thanks for your input though bro! Much appreciated!

PS : Decreasing the memory voltage in Wattman seems to help a bit with my issue. I tried decreasing it from the stock 1109mV to 1000mV and I don't get black screens quite as much. I can run my 1160/1600MHz overclock at +55mV (about 1.24V actual voltage) and I barely get any black screens now. I may get one when initially starting a game, but that's it, it won't go off and on constantly like it used to at the same otherwise settings. Or it may be something else that's helping, but so far it seems to be working, so I'm ok with it. Glad to be able to squeeze these last few MHz out of this poor card.

Phanteks Enthoo Primo, Asus Maximus VII Formula, MSI R9 390x, Intel Core i7 4790k @ 4.8GHz cooled by a Corsair H110. Corsair Vengeance Pro 16gb @ 2400MHz CL10 1.6V, EVGA SuperNova 1300G2, Samsung 840 Evo 500GB

Last edited by tolis626; 03-19-2019 at 10:44 AM.
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