You are 100% fine and in fact can run even more vcore. Most users consider anything under 1.4 to 1.425 safe for 24/7 daily use and I am in that same boat. I have had several SB chips and have done a lot of testing with them. I recommend you bump it back up to 4.5 or higher and see what it takes to get it stable.
Best way to do it IMHO, is like this. Set your load vcore to 1.4 and your multi to 45, see if your stable if so great, now try 46, if thats stable try 47. If 47 is stable go to 48. If 48 fails at 1.4vcore then try 1.425. If it's still not stable then go back to 47x and then drop your vcore from the 1.4 down to 1.385 and try that, if thats stable drop down to 1.38 try that and so forth and so forth.
The whole goal when overclocking is trying to get the most speed at the best vcore. Of course anyone can pump 1.6 volts through a processor to get 5.0ghz+, but that isn't a good use for 24/7. You can pump A LOT of voltage through SB chips for short bursts such as benchmarking but it's not a good idea for 24/7 use.
So with that being said, don't be afraid to up your voltage. Also when testing stability only use LinX or IBT with the AVX package as that is currently the BEST software on the market to test for stability. P95 is a decent program, but it will NOT push the chip to its limits/knees like the other two will. You will also notice higher temps with linx/ibt, so expect and be ready for 10c higher over prime95. Personally I wouldn't allow temps to hit over 80c MAXIMUM for ibt/linx. Again thats max max max temps, and I would like to see them under 75c if possible. However if you hit 78 on one core or 80c package max temp, it's not to big of a deal because in real world gaming or encoding you will never hit those temps.
As puppies04 said it's a good idea to use speed step technology so that at idle your chip uses less voltage. Contrary to SOME beliefs this will NOT give you bsod's or cause any issues. If you ever get a bsod it is due to system instability and has nothing to do with the down clocking of your cpu and voltages.
As far as chips degrading SB hasn't really been out long enough for a lot of people to know what is bad/good. However I can tell you that I know of a few chips running at 1.5vcore + for 24/7 use that are still doing just fine today. I have put much more then that through my chips for benching and they are all still alive too.
As far as degradation goes people need to realize that the majority of users will not have SB chips 5 years down the road. So yes, if you run 1.45 vcore 24/7 you might take 1 year off the 10yr life span or 20yr life span, but does that matter? For the majority of users, not at all. If you plan on upgrading to IB or another system within 3 years, you would be just fine running A LOT of voltage 24/7 if your system temps were within reason. Degradation isn't as scary as a lot of people make it out to be, and is something that can take a long, long long time to notice / see.
