Mistermister:
I googled "980gtx black screen on startup" which found the link " which took me to the page showing the firmware upgrade requirement:
 
 
<edit> links are stripped, fine.
the first link was on the nvidia forums, with a post entitled
Black Screen on Windows Login (344.16 and .11) on DisplayPort with GTX980 SC (Fix info posted 11/25/
the second link was to the same post which takes you directly to the nvidia official reply, stating:
This driver includes a fix for DisplayPort connectivity issues with certain monitors running on GeForce GTX 970/980 GPUs. Please give the above driver a try if you run into DisplayPort issues on your Geforce GTX 970/980 GPU. If the issue is not resolved with the driver above, check the video BIOS version of your graphics card through the NVIDIA Control Panel.

1) Launch the NVIDIA Control Panel
2) From the bottom left hand corner, select "System Information"
3) A new window will appear with information about your graphics card. Search for the video BIOS version. If the version number is older than 84.04.31.00.00, please contact your board manufacturer for an updated video BIOS update.

Please note: Before contacting your board manufacturer for a new video BIOS, we highly recommend you first test driver version 344.80 if you have not yet done so.

Decent driver for me. Haven't had any display port issues. Also, it's nice to have NVidia supporting 5x1 display configs.

spuddeh
I'm just posting so that the number of affected users is visible:
vBios: 84.04.1F.00.80
 
Looking forward to seeing the update, thanks.

My card's bios is of version 84.04.1F.00.86.  GTX 980 SC ACX 2.0 (04G-P4-2983-KR)
I don't have 4K display but Dell 27" U2715H, 2560x1440. I tried to connect my old HP Z24RW display through the second DP-port of Dell display by using daisy chain (requires DP 1.2 MST set on) but Dell went black totally and informed that there is no signal through DP input (mDP and full DP both). Only by using HDMI port display worked when DP1.2 was selected.
I have installed hot fix i.e. 344.80 drivers, custom install method. Disconnecting HP did not help. Rebooting PC did'nt help.

I have 84.04.28.00.80 on one 980 SC and 84.04.1F.00.86 on the other.  Still having the blank screen on power up issue with the 344.80 drivers and my 4k monitor.  Not sure if 84.04.1F is newer or older than 84.04.31, though if I recall my hex correctly it's older.
 
I wish someone from EVGA would chime in here.

1f is older than 28
1F = 31
28 = 40

I just installed this driver hoping it will fix my flickering and black screen issue with my 980's.

No use...still having flickering and black screens...with both cards, time for RMA maybe?
 
 

XeroHertZ
No use...still having flickering and black screens...with both cards, time for RMA maybe?

 
Out of curiosity, have you tried moving the SLI bridge to the connectors closest to the back of the card?  I had the same issue and that fixed the flickering.

I'm having this exact problem - unable to use Dell 28" 4k monitors with my SLI GTX 980s, even after the hotfix driver is installed.  My BIOS version is 84.04.28.00.80 on both cards - EVGA, what's up with this?  Should I just return the cards?  I literally cannot use my PC outside of safe mode as the monitors just shut off.  It definitely seems to be a driver issue, as they run fine with the cards at full resolution in Linux...

Now even with a single GTX 980 and no SLI enabled i'm getting this stupid flickering...i'm sick and tired of this

Pgcmoore
have you tried the new beta driver?
and 59 hz?
 

 
 

I'm using the driver mentioned in the OP but didn't try the newer one and 59hz as you suggest..will do so now and get back with feedback
 
Btw, I'm using a DVI cable connection.

Tried using displayport a few days ago, and ended up encountering a lot of issues. New drivers only made the problem worse. Now one of the 980s I have is fried(EVGA being incredibly kind about sending out a new one.) and I've since given up on displayport out of fear for what might happen. Still getting an occasional black flicker, though, using only hdmi and dvi.

One month update:
I still have the black screen on Windows start up if no monitor is connected to my HDMI port. Doesn't look like EVGA has released a BIOS update yet. Is there any ETA?
 
I started experiencing the flickering issue a few weeks after installing Windows 8.1. My system event log was spammed with nvlddmkm errors. Changing to the 347.09 beta driver seems to have resolved my flickering issue. 

i ordered a new GTX 980 from newegg so i can send my 2 780ti's in for step up this was a fresh in stock card it came with BIOS 84.04.2F.00.80 does that need an update? 

howdy2u2

dotkom
i ordered a new GTX 980 from newegg so i can send my 2 780ti's in for step up this was a fresh in stock card it came with BIOS 84.04.2F.00.80 does that need an update? 

NO!   If your new card is a 980 Classified, that is the ONLY bios for the card (part# 04G-P4-3988-KR)  They changed the VRM and made the bios to support the changes.
 
See This thread : http://forums.evga.com/GT...in-Stock-m2266825.aspx

my cards are actually the stock 04G-P4-2981-KR since that is the best the EVGA step up program would allow coming from a 780 ti they must just release them with the 84.04.2F.00.80 BIOS as well.