OK, let me try and answer some of the questions you've raised......
First, I fat fingered the memory in my card as it only has 1 GB of GDDR3 memory. Sorry about that.
I have not actually timed the black screen issue but in my opinion the time lag is about 1 minute. Once the black screen has gone away and is replaced by the login screen the machine works flawlessly.
If you go to the Sapphire website and try to download a driver from them they will provide you with a utility provided by AMD which will tell you what the latest driver for your OS is and point you to that driver on their (AMD's) website. So, in this case it doesn't make any difference if you go to the Sapphire web site or AMD's web site the only driver your going to get is from AMD's web site.
My concerns are that I believe that I tried out the most current driver a year or so when I was running Windows 7 and had some issue that caused me to back level the driver back to a previous driver. Unfortunately, I did some cleanup on my PC and I no longer have the driver that I'm currently using. Even if I did have the driver I'm using I'm concerned that in uninstalling and then reinstalling the driver my system might become corrupted and then what would I do. Right now, at least, I just have to put up with a 1 minute delay during the boot.
Additionally, I'm just a bit concerned about support. I have an issue today that may or may not be caused by the video driver but what happens if something else gets upgraded or changed and that causes a graphics card issue. What do I do then as I already know that AMD is not going to support my card. For me, although it is an expense, I think I would be more comfortable just getting a new card that would probably last me as long as the rest of the hardware will last.
As far as cost is concerned I think I want to stay at or below $200 but would be willing to go over $200 a bit if necessary to get a quality card. Naturally, since I'm not much of a gamer, I don't need a high zoot gamer card. On the other hand, I want to have a card that's fast enough that my system performs well. The qualities that I'm looking for in a card are support, priced right for needed performance, cool in terms of heat generated and quiet.
In regard to the power supply I have not checked this out but I know when I built the system I put a quality power supply that people were suggesting was overkill considering the devices that it was powering which are 2 DVD's, 1 HDD, and the graphic card that gets it's power via the motherboard.