Is my 850W PSU enough for a single HD 5970?

850TX is more than enough for a 5970. A 750TX can run two 5870s and a 5970 is two underclocked 5870s so it uses even less power. No single card is supposed to use more than 300W of power so the 850TX is more than enough for any single card.

Thanks! How much of a bottleneck is my Core i7 930 at it's stock speeds? What are the average idle and load temperatures of the HD 5970? It's still a lot lower than the GTX 480. The HD 5970 is currently the fastest GPU money can buy. It should be able to handle almost any game at it's maximum settings and give very nice framerates, except for Crysis.

i7 isnt going to be much of a bottleneck, especially once you start cranking up graphics settings. I dont think there are average load and idle temps for a 5970 as that is heavily dependent on case airflow. Hopefully your load temp is below 95C, and ideally below 80C.

The program used to test graphics cards to see their maximum temperature, power consumption, and fan noise is Furmark. Not even Crysis can push a GPU as hard as Furmark can.

The Core i7 930 (at it's stock 2.8 GHz) might be a slight bottleneck for the HD 5970. I have no experience in overclocking, and I care much about my warranty and not damaging my CPU and other components during overclocking.

Haha wait, did you just ask a question, turn down the answer, and then make up your own? xD (And he knows what Furmark is.)

An i7 930 is a fantastic chip... it will not bottleneck a 5970. Maybe if you play at 1280x768, but you'd already have 200fps, so who cares.

And... overclocking is a choice, yes, but it's very safe if you know what you're doing. That's what forums are for. =]
In fact, AMD and Intel market and plan on their CPU's being overclocked, that's what unlocked multipliers are for.

Yes, overclocking is extremely safe these days. Current chips have an almost excessive amount of safe guards making it nearly impossible to damage your system even if you were to purposely set out to do so. I don't believe it should void the warranty either and even if it did they will only know you OCed if you tell them.

Changing the speed or voltages of your CPU, RAM, or GPU instantly voids both the manufacturer and any store warranty the very moment you do so.

I do not know of a single hardware manufacturer, or PC store whom will allow you to keep your warranty on a component if it has been overclocked in any way. If it breaks, you have to pay big $$$ for the repair.

Most pre-built PC's, especially from Dell or Gateway, have overclocking features permanently disabled in the BIOS by the manufacturer, even if the motherboard and BIOS naturally support overclocking. Such as my current Gateway FX-6710-01 desktop has.

I bought a ZALMAN CNPS9900 because the stock Intel cooler the Core i7 930 came with is notorious for being an inefficient piece of junk, and because it was on sale for $40. Processors run extremely hot using it, even at their stock speeds. My CNPS9900 cooler isn't the best, but it's sure a heck of a lot better than the stock Intel heat sink and fan. Most of the reviews I've read for it have been widely positive, it should also give me a bit of overclocking head room when I feel good and ready.

I meant the warranty on the CPU from Intel.
Obviously Dell/Gateway/HP/ect. don't like it and usually even make it impossible. This one of the reasons why it best to build your own computer(among many others.) But like I said, they can't know you OCed unless you tell them.
If your processor is running "extremely hot" on the stock fan/heatsink that likely means your case has very bad airflow.

First to answer the original question: Look at this review. Clearly the PS is sufficient for your application.
http://www.jonnyguru.com/modules.php?name=NDReviews&op=...
Yes if you toast your CPU by overclocking, then you made a mistake and no company guarantees for user errors. If the cpu fails because of manufacturing faults it gets replaced. jvjjy is correct there is no way to tell if an oc has been done. As long as you apply voltages within the safe limits of the device and control the heat issues all will be well (and you must choose quality mb, ps, mem and cooler). If your system plays your games smoothly and runs your applications at it's stock settings you might leave it alone. If you need more "speed" to run things the way you want or just want to have more performance oc it "prpoerly". Have fun.