How many Watts do I really need for my PSU?

[refllect]

I have an i3 3245 on an H77 motherboard with a HD 7770. Some sources say the minumum PSU I need is 500 watts for a 7770. Others say that 350 watts is enough.

How exactly do I calculate this? People tell me you can't just add up the Watts.

 

[smeezekitty]

500w for that system is overkill.
A GOOD 350w PSU (Like an Antec Earthwatts 380w) would be enough
Or a Corsair CX430 would be good.

Food for thought: My system Core 2 Duo + 6670 draws 150w at the wall under full load.

 

[quicksand10]

^+1

The Corsair CX430 is an excellent choice
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026

If you're looking for a cleaner case, opt for the modular version:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139049

 

[refllect]

^+1

The Corsair CX430 is an excellent choice
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139026

If you're looking for a cleaner case, opt for the modular version:
http://www.newegg.com/Product/Product.aspx?Item=N82E16817139049

Oh I forgot to mention that it was for a micro-ITX case that only holds SFX form factor PSUs. So 450w is as high as they make them. I wonder if I can fit a better card in for 450w

http://www.newegg.com/Product/Product.aspx?Item=N82E16817256063

 

[quicksand10]

Ah, okay then.

I'd suggest the fully modular, 80PLUS Gold rated version of the PSU you posted.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817256084

Here are some reviews for both models:
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=196
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=319

In a tiny case, you want good airflow, and a fully modular, efficient PSU is helpful for maximizing airflow and thus keeping temperatures and noise levels to a minimum.

 

[refllect]

Ah, okay then.

I'd suggest the fully modular, 80PLUS Gold rated version of the PSU you posted.
http://www.newegg.com/Product/Product.aspx?Item=N82E16817256084

Here are some reviews for both models:
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=196
http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=319

In a tiny case, you want good airflow, and a fully modular, efficient PSU is helpful for maximizing airflow and thus keeping temperatures and noise levels to a minimum.

Do you think I could put in a better graphics card for that PSU?

 

[smeezekitty]

You could probably go up to a 7850 with no problems