That SAGA of the used HD 7950 and 4K!!! :)

[James Steele]

I renamed the topic... it HAS turned into a SAGA!!! Looks like I'll have to buy another card. Seller will not refund. They did get back to me when I texted them. Husband and wife who sells stuff on Craigslist who by their own admission are "not very technical." I suspect the husband dabbles in a bit of everything and saw a YouTube video of flashing PC cards. The kicker: he had never tested the card on anything other than a single 1920x1080 display. Not much of a stress test. My 2560x1600 30" Cinema and 23" Cinema 1920x1600 combo was the most action this card had ever seen. Looks very much like a thermal issue is generating heat and either seizing up my Mac... or seizing the GPU which logically, IN TURN, is seizing up my Mac. Yeesh. More to come. I have to step away from this until tomorrow afternoon.

[James Steele]

Okay.. last entry because I have to get out of here to an event I'm working on.

I just ran the computer with open DP project for an HOUR... but with the fans cranked up to 3,000 rpm. No freeze up. The one "problem diode" that would end up at 175 degrees F or even 179F at the end when it froze up, reports 40 degrees cooler. 135F. I'm guessing it's a thermal issue. I probably need a card, but tomorrow I may inspect it and see if fans aren't working and it's not pushing the hot air out of the case as it should, or something else that's visually apparent. HC Markus is going to be kind enough to loan me an RX460 just as a test to make sure it will work for me before I buy one, but if I were a betting man, I'd say this is all about HEAT!!

[monkey man]

Yikes!

So sorry my "brainwave" didn't work Brother Jimbo.

[James Steele]

Yikes!

So sorry my "brainwave" didn't work Brother Jimbo.

Hey it MIGHT have worked and I thought it DID! Good try! And it might contribute to it, as I was using a cheapo cable. Shows how trouble shooting is so tricky. Now that it worked when I manually set the fans so high and kept the case cooler I’m pretty sure it’s a thermal issue.

HC Markus is going to loan me a different card just to verify and perhaps then try to buy one like his. I’ll also inspect the card giving me problems. Perhaps fans aren’t working and it’s not expelling the hot air out of the case as it’s supposed to?

[HCMarkus]

It is very possible that re-pasting that GPU will resolve the issue. Something to keep in mind, maybe worth trying before spending $$$ on another card.

[James Steele]

It is very possible that re-pasting that GPU will resolve the issue. Something to keep in mind, maybe worth trying before spending $$$ on another card.

Could be. Hopefully that’s an easy visual inspection. Or I can just go ahead and do it and see what happens. Need some paste. Wish you had more time today. I could pull it before I come over and bring it by.

[HCMarkus]

I have more time; its just the time I have and the time you have don't overlap very much!

[James Steele]

I have more time; its just the time I have and the time you have don't overlap very much!

Haha. Yeah. It’s a bad week for this to have happened. LOL

[James Steele]

Brief update. It appears to have been a thermal issue. Big thanks to HC Markus for the loan of his card and hipping me to Macs Fan Control. My Mac seems to have been shutting down when the Northridge Diode got too hot. I leaned from HC that the BOOSTA fan had the most targeted effect on that diode, so using Macs Fan Control I was able to link the speed of the BOOSTA fan to the temp of that diode. Now I can use the HD7950 and it won’t lock up. The fan can spin up to 2500 rpm or more sometimes but it is not objectionable and far quieter than the brute force approach of boosting the intake and exhaust fans.

[monkey man]

Awesome sauce, Jimbo, and well done to Brother Sir Markus too!