PSU wattage - 300W or 450W? Confused!

[kskarun]

Hi,

I'm building a new system with the following components:

Gigabyte EP45 UD3P
Q6600 & Arctic Cooling Freezer 7 Pro
OCZ Reaper 4GB @ 800MHz
HIS HD 4670
2xWD 640GB Black Caviar
19" TFT monitor

For calculating the PSU requirements, I used 2 websites, and came up with 2 different wattages. (I used a voltage of 1.4 @ 3.0GHz for OC - just pulled those figures out of thin air to see what numbers I get.)

http://www.extreme.outervision.com/PSUEngine gave me 265W, and 300W with OC

http://web.aanet.com.au/SnooP/psucalc.php, however, gives me 393W, with 455W for OC.

(The second website doesn't list 4670 as one of the video card options, but I selected 4870 and overrode the core and memory values as listed in the specs of HIS HD 4670. The calculated wattage for the card alone was 137W, which kind of compares with reported average consumption of 140W.)

Which calculator is more accurate and closer to the actual values depending on your experience?

Thanks a bunch for your replies!

[RollingThunder]

Hi,

I'm building a new system with the following components:

Gigabyte EP45 UD3P
Q6600 & Arctic Cooling Freezer 7 Pro
OCZ Reaper 4GB @ 800MHz
HIS HD 4670
2xWD 640GB Black Caviar
19" TFT monitor

For calculating the PSU requirements, I used 2 websites, and came up with 2 different wattages. (I used a voltage of 1.4 @ 3.0GHz for OC - just pulled those figures out of thin air to see what numbers I get.)

http://www.extreme.outervision.com/PSUEngine gave me 265W, and 300W with OC

http://web.aanet.com.au/SnooP/psucalc.php, however, gives me 393W, with 455W for OC.

(The second website doesn't list 4670 as one of the video card options, but I selected 4870 and overrode the core and memory values as listed in the specs of HIS HD 4670. The calculated wattage for the card alone was 137W, which kind of compares with reported average consumption of 140W.)

Which calculator is more accurate and closer to the actual values depending on your experience?

Thanks a bunch for your replies!

The former is closer. A Corsair VX450 would handle that system just fine. That 4650 draws about half of an overclocked 4870.

[kskarun]

Thanks for your reply RollingThunder.

I spent more time with the eXtreme PS Calculator (Lite) and came up with the watts per component given below. I did this by hitting Calculate every time I added a component. Not scientific, but this kind of gave me the increase in wattage calculated when each component is added.

Gigabyte EP45 UD3P - 46W
Q6600 2.4GHz - 73W
OCZ 2x2GB DDR2 800MHz - 9W
Western Digital 640GB SATA - 24W
HIS HD4670 - 43W
DVD R/W - 26W

(How do I add tables to a post?)

I don't about the other parts, but looks to me like the wattages for CPU and the video card are on the lower side. Moreover, if I enter OC values for the CPU (3GHz @ 1.4v), the CPU wattage goes upto 149W (up by 76W), but the overall wattage increases by a mere 35W!

Are these values correct? Am I missing something blindingly obvious?

[burebista]

Your mistake was choosing 4870 underclocked for HD4670. :)
A closer choice is HD2600XT.

http://www.xbitlabs.com/images/video/powercolor-pcshd4670-512mb/4670_power.gif

With your specs (Quad G0, 2 HDD's, 1 DVD, 2 sticks DDR800, 2x120mm case fans) and HD2600XT I have 172W while gaming and they recommend a 280W decent brand PSU.
I'd say that Antec EA380 is enough for your setup.

[kskarun]

burebista: Thanks, I was rewriting my reply (above your post) while you posted. I see what you mean. Would you recommend the same PSU even if I want to overclock my Q6600?

Thanks for the catch!

[burebista]

We have here a thread (http://www.ocforums.com/showthread.php?t=511180) about EA380 powering E6600 @3.6 and one 8800GTX. Read it and see yourself. :)
But if you tell us your PSU budget maybe we can pinpoint a PSU for you. :)

[kskarun]

burebista: Thanks for the tip, am reading it right now.

Well, I'm in India so budget may not be relevant (a PSU that sells for $100 in USA may sell for an equivalent of $130 here). But if you point me to good PSUs (Antec, Corsair, etc I suppose?), I'll see if I can get the same stuff here.

[burebista]

If you can find Corsair CX400 it would be perfect. Otherwise Antec EA380/430 are next choices.
Fortron Bluestorm II 400 is a good PSU. I dunno what you have there.

[kskarun]

Thanks for your replies. Corsair and Antec are popular brands here, so will try those out.

[RollingThunder]

Thanks for your replies. Corsair and Antec are popular brands here, so will try those out.

Burebista also gave you some good choices. If you overclock your CPU and single GPU, add about 50w - 60w total depending on how much your overclock is. It's hard to say what an overclock requires because different CPUs and GPU make it vary. I suggest using that figure as an approximate. It can vary.

If you decide on an Antec, make sure it's their newer models like the EarthWatts, NEO HE, and not their older Smart Power and True Power models.

Those online tables for estimating wattage always seem to be on the high side and I take them with a grain of salt. My rig in my sig is always estimated at about 320w - 330w but if you break each component down like you did, it's about 270w including my 10% overclock.

[kskarun]

Thanks a bunch for your replies. That helped me a lot to clear my confusion.

[unrlmth]

I would get a little bit more than you need, just in case you ever want to add more HDs or a WCing setup. And its not good to be running your PSU for max load all the time.

Corsair and Silverstone make some very nice units.

[kskarun]

unrlmth: Thanks for the tip. I don't think I'll go the route of WC'ing - I'm not so much of an enthusiast. I live in a climate with humidity around 85%, so water cooling is probably more trouble than its worth. But yes, I am allowing for some head room and aiming for a 450-500W PSU.