120Hz monitor only working at 60?

I have a ASUS 120Hz monitor, and a GTX590.

I have been using a DVI cable for the last year or so.

The other day I turn on my PC and all the fonts look crazy and blurry.

If I turn the monitor down to 60hz it all looks ok again?

How can I tell if it is the GPU or monitor with the issue?

Well if you hook up the monitor to a different GPU then you can elminate both i think.

What TD said... You could also try:

• Using a different input like Display Port
• Using a different DVI Cable
• If you updated your GPU Driver recently... Uninstall it and roll back to a earlier version

Doing all of these things would cover all basis from cable, input, monitor, gpu and driver... You should be able to figure out whats wrong.

Restart your pc if you haven't already. I've had a similar issue before and that worked for me.

Pretty much this, either hook to different GPU or hook a different monitor to the same GPU.

You are using a Dual-link DVI?

@Grey_Eyed_Elf: @TDuiker

I only have the one GPU, one monitor and one dual-link cable :( lol

OK, so I have the pointers to try and narrow down the issue, will need to go borrow some hardware and see.

I think he knows that, since he turned it down to 60..

Talking of more then 60hz. No matter what i do on my TV with game or nvidia graphic options it either gets screen tearing or slows right down either with Vsync on or off etc. Would a 100hz TV get rid of the screen tearing all together?.

Apparently you didn't read the original post.

@jimmy_russell:

It was all working @120, then it stopped working. That's the issue. The cause is what I am now trying to determine.

Just wanted to see if anyone had experienced it?

Got some good ideas on how to narrow it down. Have now ordered a new cable. See if that helps.

So all in all, a really helpful thread for me.

Thanks