just a quick calculation

old sys cpu 90watts,md 30watts,hdd 30watts ram? 20watts? old gef8600 200watt??? old system estimated draw 370watts total< 500watt psupply should work fine

new sys ,90watt cpu,mb 30 watts, 30watt hdd, ram 20watts? newgef980gtx+  450watt estimated draw is 620 watts total >500watt psupply no boot

based on the fugures I would recomend budgeting atleast a 750watt supply as well as the card

hope this helps you

harpo

or boot with no video..

Haha, I get super cheap stuff from Newegg and my Graphics card is actually total crap, it can't even run Morrowind GE edition at a stable frame rate (granted, it's an Oblivion esque look alike in GE mode) and I never had those probs on my old 7900 that blew up.

I misphrased the 450 watt drain thing, it actually drains more like 300 or so I think (I'll speak directly with an XFX guy in the morning, but support tickets are super freakin slow), 450 (With 350 being the minimum recomended for the Geforce 8600 I already have) is the minimum recomended to run on most systems, but even then, yah, I'm super iffy about getting it anyway, but if I can, I'm getting it at literally 1/2 the Retail price, so if it doesn't boot up, no biggy.  I absolutely ABHOR changing power supplies, I'd rather get an entirely new system before changing PSU's

The voltage rails are what I'm concerned about, because if I boot up with insuffucient wattage, there's no real damage that can be done (that I know of) however, messed up Voltage rails can fry PSU's and graphics boards.

**It looks like according to Nvidias Site (Unless I suck at reading and inturpreting which is quite likely) The GTX+ 's peak power usage alone is 141W

"Minimum SYSTEM power requirment" 450W"

Maximum Graphics card power: 141W"

Did I misinturpret that (Sorry for question spam you guys are bein super helpful tho and I'm a little noobish at this, I'd rather ask stupid questions and feel like an idiot than blow up my PC lol ^^)

Split-rail PSUs cannot actually deliver the full total on both simultaneously. The actual capacity is generally 2/3 to 3/4 of the sum at best. IIRC the recommendation was ~16A for CPUs alone last I checked, so you definitely need more.

80PLUS (which itself only applies to the relation between line draw and actual supply) only requires a 0.9 power factor at full load, and full load is not something you want to be running at for any extended period. But even still that's only a measure of efficiency, which is not the same thing as capacity.

Just for example, looking at a basic Antec 550 PSU (not 80PLUS, so while a bit exaggerated, the same rule still applies), it claims to offer three 12v rails, at 22A/22A/25A, which totals to 828W. And yet the actual maximum draw on those lines combined is only 384W... which gives a max combined current of only 32A. As you add more rails, it only gets worse, and on top of that you have to try and balance the loads on each to get the best efficiency.

One rule of thumb i've always followed is that *Do not try making a "normal stock manufactured for a purpose" mobo to become a BETTER gaming gear than it already is.

Overclocking, wrongfully matched PSU to board specs, up railings (direct or otherwise, btw) can only lead to -- sadly-- an eventual fried Tower as a whole.

Sure, new technology equals performance but you have to make a choice sooner or later... BUY a pre-built wonder instead of upgrading this & that & other stuff until the Hardware infra-structure becomes an hybrid so tied in chaos voltage that it WILL fail at one point.

Trust the companies who build PC packages, they electronically stabilized the entire set while giving some leeway in upgrades that may fit specific needs.

Not enough, change the entire thing.

Believe me, i fried many good PCs with ambitions beyond characteristics. In the long run, it wasn't worth it.

Now, the Graphics card; again, it's a matter of mobo capacity. It's a general industry growth where power comes at a price - you guessed it - closely dependant on the Tower limitations. Sure, a PCI has appeal... but i ran an old AGP for years without any flaws while keeping the entire 'structure' as built. Eventually, i too went for Vista, i even snapped a GE6400 to replace an MX4400 on a Pentium IV board.

Today, i do have a Dual Core CPU... and i wont slap a 750W PSU on that thing simply because ACER built-it with another strong enough for what i need. It doesn't mean that the 386DX40 i enjoyed back then wasn't made for minimal gaming either - it's just that a hardcore gamer should own a different (or ever soooo slightly enhanced)  PC than some casual desktop gear.

Essentially, every assembly of components that differs (too much, btw) from recommended usage can burn a mobo & plenty of other stuff beyond repairs.

Lucky us, SATA drives are slowly entering the Terabytes realms - don't try plugging it in on a PC that can't handle it though.

Strongly seconded. I own one of these and it is a brilliant card. It will run games such as Fallout, Demigod, or Empire Total at ultra-high settings with no problems.

My rig is set up similarly to yours. I have a dual Athlon proc (2.8), 4 gigs ram, 2 hard drives, and of course, the 4850. I run all this with a 430 watt Thermaltake ps, and have never had an issue at any load. Heck, the thing barely gets warm.

My advice is to go with the 4850. Chances are it will work just fine, and save you a few ducats in the process. I know you have an SLI mobo, but unless you are planning to buy a second vid card in the near future, it really doesn't matter.

I have a 4850x2 and it rocks. The 4850 chip is the most under estimated video out there. I strongly recommend it. For power 650 is minimum, 750 gives you more room to expand.

I'm running a 4850 x2 with Phenom 2 940, 8 GB ddr2-1066 and three 160 GB striped with two DVD burners on a 650 with no power issues at all. But it is a very good 650.

i think you're over-estimating power needs just a bit; most people do, and of course it's always nice to have more than you need (i certainly do). i still don't think the OP would need to ugrade his PSU for a 4850 if his PSU is decent quality.

You deffinately NEED to upgrade the PSU. the above the info is great info. Yes there is the possibility of no boot or boot with no video. this would be due to lack of power. What I did not see mentioned is that the lack of power that will cause this is even more serious. 

the fact about under powered PSUs is that they WILL, sooner or later,fry system hardware. usually the VGA (Video) card is the first to go because it is usually the single most power demanding componet, and then possibly followed by the motherboard, etc...

Trust me.. I learned the hard way and lost both a VGA and Mainboard within a week of each other.

I would suggest:

1. read this it will explain Why your PSU is so Important as well as other aspects of the PSU such as efficiency rating (ie. it's not just the rating but at what temp it was rated) as well as Why you should run a PSU that is AT LEAST 30% larger in power capicity that what your system demands.

2. Visit JonnyGuru.com Possibly the BEST site concering PSUs. They extensively test PSUs and rate them. They also do not recommend a PSU unless they can give it a 9 or better rating on a scale of 1-10.

use both of these to make an Educated purchase on a new PSU.

3. I would strongly suggest (as others have) NO Less that a 750W 60A PSU. My personal favorite is the PC Power and Cooling 750Quad. as well it is one of the FEW that JonnyGuru gives a 9 or better rating. 

4. IF You take even just one thing out of all this REMEMBER THIS! It is NOT ALL about the WATTS, but rather about the AMP output of the PSU.

while your at it you may want to consider upgrading your CPU. You can do that for under $100 at newegg. I would suggest the 5000, 5400, or 6400 Black Editions if you can find them, or the 6000.

these are great points, and i hope it didn't seem that i was indicating otherwise. however one thing i'd point out is that you do continue to pay for a beefier PSU than you need, assuming you pay your own electricity bill -- even when they are highly energy efficient. that said, i personally prefer to err on the side of caution in these matters, myself. i've got a 700W PSU in a system more modest than the OP's.

i think the question of whether it's a definite need depends entirely on the quality of the PSU. if it's a good PSU it should be more than enough. as a basis of comparison, the electricity consumption of intel's skulltrail system with dual 8800GTXs and all the fixins was measured at the wall at less than 600W (reference here:
http://enthusiast.hardocp.com/article.html?art=MTQ1OCw3LCxoZW50aGlzdWFzdA==

of course i wouldn't want to put a 600W PSU into that system. still, i think 30% above needs might be a little high; and it's also worth noting that most PSU calculators automatically add 10-20% "overhead". in either case, i think a good quality 500W PSU should handle an athlon X2, a 4850 and the rest of his system well enough. i didn't look into his PSU to answer that question, and i don't know if you did (so please accept my apologies if you did and you were making your recommendations based on that knowledge). in either case, kudos for providing good references for the OP to make an informed decision.

I assume that's the question you're referring to.

 
You can use the 6 pin PSU plug and one adapter (two adapters will not work). If the PSU cannot supply adequate power to your system, it won't boot.....

.....if you're lucky, that's all it'll do.

Like I said, use the GTS 250 when it releases real soon, don't try to get the 9800GTX+. The GTS is a rebrand of the card, but it's shorter, quieter, cooler, same performance, and here's the kicker... Only requires ONE PCI-E 6-pin connector!

http://www.anandtech.com/video/showdoc.aspx?i=3523

And for those who keep saying you need a 750+ watt PSU, please, stop saying that. I'm a computer tech for a low-pro computer store, and we get tons of business (Because we're cheaper), and half of those customer's need a new PSU... Never have I once underestimated anything, even for a gaming machine. 750WA is a LOT of power, mainly since 90% of them on the market are 80+ certified, giving it a longer-lasting drive, since it's peak at 80+ is like, 825WA or some junk.

Your current 500wa with that system will be more than enough. However, it is recommended, since it's a rather older PSU, that you upgrade the unit eventually, when you have the money. If it goes bad, there's always a chance of taking the system with it.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817371007

or if you want something with a bit more kick,

http://www.newegg.com/Product/Product.aspx?Item=N82E16817703005 would be more than you would ever need for a mainstream video card, like the 9800GTX+. Right now, keep in mind, it's not a requirement, but a recommended buy for the near future.

PS: If you didn't care for the ATI cards, I'd say wait until the RV740 card comes out (HD 4770 DDR5), as it'll be under 100 smax, and give you fairly close performance to the 4850/9800GTX cards, if not more. April.