i am having a hard time choosing between which 7950 to choose from on new egg. i was going to go with the saphirre but someone mentioned that voltage was locked not sure what that is but in the android community when a boot loader is locked its not good.
For AMD cards Sapphire makes really good cards, and from what I know the voltage should not be locked. When using overclocking utilities such as MSI Afterburner or Sapphire Trixx you should be able to adjust the voltage on most cards. From what I have read some of the cards (Sapphire Vapor X) come with a voltage locked at 1.25v.
From what I read only a fraction of people have a locked voltage, but if you don't want to risk having a locked voltage, you could go with another brand. Check out some of the Asus DirectCu (do note that some of the asus cards used to have issues where the heatsink wasn't properly mounted causing overheating), Gigabyte Windforce, or a MSI cards. However it is strange that some people are getting voltage locked cards, apparently some cards from various manufactures are arriving voltage locked. Some people say that they set a fixed voltage to get around this though.
If I were purchasing a 7950 I would go with the Sapphire Flex version. What is nice about that card is that it is not oversized (means you can crossfire in the pci-express slot that is +2 from the first card, which is usually the next x16 slot if that matters at all. This also leaves the option open for triple crossfire if your board and psu would support it.)
The other thing that is great about that card is that you can run a triple display eyefinity setup out of the box. Most other cards will all require you to purchase an additional Active display port addapter, which nowadays cost around $30.
That's my two cent on the matter. I'm currently considering buying three of those cards right now, but may just say screw it and get 3x 7970s but we'll see. I'm not sure if I can justify spending $1200 on my graphics subsystem.
As far as the voltage lock on cards go, I believe you will find that all manufacturers are starting to employ this on their non-premium cards to justify you spending your dollars on "unlocked" versions. It's AMD's fault for making such a very overclockable card!
I would recommend Sapphire too. Go look at retailers and you are bond to find cards on sale. I got my 2 Sapphire HD 7970 for 409 but I will also be getting $15 rebate for each so pretty much @$394.99 each. So if you can afford it get a 7970 if not then stick to a 7950!
Even the voltage-locked cards can get their voltage unlocked if you really want to it.
Also, I'll bring another suggestion to the mix. The Gigabyte WindForce x3 7950 is unchanged AFAIK from when it firsts launched as one of the first 7950s, so it's not only one of the better=binned and cooled models, but it should always come with unlocked voltage and be one of the best cards for overclocking. It's cooler is also said to have the best cooling to low nose ratio of all the top end coolers