8800 or 3870 PS requirements

[50bmg]

I have a question on power required for an Nvidia 8800GT and ATI 3870 with a Core 2 Duo.

I am running a P4 3.0Ghz HT, 1 HD, 1 CD, 1 DVD, Nvidia 7600GT, 4 512M modules of 533Mhz DDR2, 3 fans, no usb/firewire devices, no other cards or drives. I currently have an Antec 500w ps. It has 2-12V rails, both 18-19A with a 6 pin SLI plug.

using the following calculator
http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us
It says i will need 650 watts to run an Nvidia 8800. It doesn't specify GTS, GT, etc. The calculator doesn't have ATIs 38XX cards listed yet. But it says the 650w for the HD2900 as well.

Will i need to up my ps to 650 watts to upgrade to a 8800 or 3870? My MB will also support Core 2 Duo, so will upgrading my CPU add to my wattage requirements?

I have read many of the reviews and benchmarks, but they are back and forth. I need some real world advice.

Thanks

 

[Onus]

I think that PSU calculator is way off. To run a 7900, it said "400W," but changing to a 8800 bumped up to 600W. I don't think so.
Using the PSU calculator located at http://www.extreme.outervision.com/PSUEngine, I saw a jump from only 281W up to 332W for the same configuration.
For your requirements, a quality 450W-500W PSU should be sufficient, including a comfortable margin. Choose one from Tier-3 or better from the list at http://www.tomswiki.com/page/Tiered+PSU+Listings?t=anon.

 

[WR2]

Will i need to up my ps to 650 watts to upgrade to a 8800 or 3870?

8800GT/GTS or HD 3870 will not need a PSU upgrade.
7600GT requires about 50W and both 3870 & 8800GT about 105W at peak.
The Evga website recommends a 400W PSU with 22Amps. Evga 8800GT recommeded PSU (slide down the specs to see PSU data)

Upgrading your CPU from P4 3.0Ghz to C2D E6420-E6850 will lower your total wattage by about 20watts. Overclocking the E6420 to 2.66Mhz would have you back up to near the same wattages you are using now with only a CPU upgrade.

 

[TheGreatGrapeApe]

using the following calculator
http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us
It says i will need 650 watts to run an Nvidia 8800. It doesn't specify GTS, GT, etc. The calculator doesn't have ATIs 38XX cards listed yet. But it says the 650w for the HD2900 as well.

Well first thing, I doubt the GF8800 listed in that is a GT as it just say GF8800, and the GT draws a little less than a GTS and noticeably less than a GTX/Ultra (which is likely the high side of their reco). And similarly the HD3800 draws significantly less than the HD2900.

I would say you should consider the power envelope for your PSU as 150W on the safe side, and actual draw closer to just over 100W.

So based on what you have already these will likely draw about 50-75W more than the GF7600GT, and should be able to be handled by your PSU.

I'm not a fan of ANTEC PSUs, but I think yours should handle these cards well.

 

[ramo]

Power requirements for the 3870.
http://www.guru3d.com/article/Videocards/472/8/

Power requirements for 8800GT
http://www.guru3d.com/article/Videocards/468/3/

They both need a 450W psu with 26 to 28amps on the 12V rails to be one the save side.