I built a new PC which included a Radeon HD 6870. I plugged it into my PSU and it didn't have enough power to run it. So, fast forward a week. I got a new OCZ ZT Series 750w PSU. When I hook the card up to it, the computer cuts on, but I get a black screen. Theres no post beep or anything, just black. So I Decide to switch back to my old card a GTS 250. The problem being that now my old card is doing the same thing.
Also I should add that with my old and new PSU the computer would sometimes not want to cut on I would have to jiggle the 24 pin cable around on the mobo and it starts up. I'm thinking there is a problem with the mobo. I'm currently going to replace it and the video card.
Also I wanted to ask with the 6870 I'm using a VGA to DVI converter (Didnt come with the card.) I've heard that not all DVI ports support VGA converters though. The card, under the first dvi port has VGA written under it but I figured it wouldn't hurt to ask if it would work on here.
It sounds like you have a bad connection on the mobo and I wouldn't mess around with it untill you can have someone take a look at and If it is still under warranty get them to replace it. It is not good to have full power coming from the psu and off again it would be like a surge of power all at once. Good luck
Change the Motherboard? The Motherboard maybe isn't good because you are I think trying to say that your old motherboard works on gts 250. Also, before you are going to change your motherboard first check if the connections of the power cables from the PSU are correct Mostly I about the 20+4 pin ATX Motherboard connector from the power supply. And another question: is FX-4100 Good? I hear reviews about it on legit reviews but They seem strange to me they said it is recommended and outperform i3 2100 in gaming, but most of the people said that It is crap and falls between Phenom II X4 and X3 in performance. Just to clear this up .