Corsair VX450 and 2900XT

[EarthBoy]

Hey

So i was considering upgrading to a 2900XT, and to do that i need to get a new PSU. i was looking at the new Corsair VX450 but im confused about the power requirement of the 2900XT. do i have to have two 6 pin PCI-E connectors? also does the nV 8800GTX require two 6 pin PCI-E connectors as well? im pretty sure the GTS only need one

thnx

 

[RussianSensation]

2900XT has 6 pin + 8 pin but you can run it 6+6. The extra 8 simply lets you enable Overclocking in the control panel of the drivers. 8800GTX has 6+6 configuration and 8800GTS has one 6 pin connector. If you buy the cards retail, all of them will ship with adapters so you do not have to worry if your power supply has 2 x 6pin PCIe connectors (but most modern PSUs do anyway).

Is there any particular reason why you are choosing HD2900XT over 8800GTS 640mb? What resolution do you plan on gaming at and how often do you upgrade graphics cards? If you play at 1600x1200, it is sufficient to have 8800GTS 320mb for $260.

Welcome to AnandTech

 

[John]

Earthboy should consider an EarthWatts psu.

The VX450 only has a single PCIe connector, but it will easily power a single 2900XT or 8800GTX/Ultra using a molex to PCIe adapter.

 

[CrystalBay]

John is right again....

 

[mpilchfamily]

You guys put too much stock in to the Earthwatts PSUs. Problem with them is they are dual rail PSUs and the amp rating on the rails are low. 17A per rail isn't much for a high wend system using an 8800 or 2900. one rail is used for powering the CPU and possibly the motherboard leaving a single rail for everything else. The 17A rating on the rails is the max rating only meant for peak loads. Its not able to sustain that load for long. If it does you will run into power issues. That 17A can been eaten very quickly. Lets take the 8800 GTS. It uses between 9A and 11A depending on the load. Then you have a HDD and Optical drive each of which will pull about 1.5A. Then fans and lights may pull at most 2A. So your already looking at a total draw of about 14A to 16A. So you are heavily stressing the PSU. Not a good idea. This is why i never recommend a dual rail PSU for a system with these higher end video cards. Unless the PSU is rated over 20A per rail. The 500W unit is rated at 34A on the combined +12v rails. This is very unlikely, you almost never see a quality PSU where the combined +12v amperage is the same as adding the 2 rails together. Besides to get a full 34A out of the unit you would have to OC the CPU to the point that it and the motherboard are pulling the full 17A. There is always some leftover unused power that can't be tapped. Total +12v amperage isn't the full story on PSUs. You have to consider the distribution of the power. Particularly on these dual rail units.

 

[mpilchfamily]

To the OP.

Yes the Corsair VX 450W will suit your system fine. Its a single railed unit with 33A max output on the +12v rail. You may want to go with the 8800 if for no other reason then to save you some money in the long run. You will have great if not better performance then the 2900 and you would need as much power. With the 8800 at most you'll need 28A from the +12v rail for the total system. Since the PSU is a single rail then the power is easily distributed among all the components. You don't have to worry about over taxing a single low amperage rail. The Corsair VX models are an overall better option then the Earthmatts units. I don't care if the Earthwatts have slightly better eficiency.

 

[JEDIYoda]

The earthwatt can handle easily what earthboy in wanting a PSU for!!

As usual John is right on the money!!

 

[mpilchfamily]

There is more to it then the total +12v amperage.

 

[John]

Originally posted by: mpilchfamily
You guys put too much stock in to the Earthwatts PSUs.

Not really. My initial statement was poking fun at the OP's user name. Have another look and maybe you'll see the relevance.

Problem with them is they are dual rail PSUs and the amp rating on the rails are low.

According to jonnyGURU the EarthWatts EA-500 does NOT have multiple +12V rails. It only has one (34A) +12V rail with no limiters on any of the connectors.[/i] It was also awarded a 9.5 (out of 10) for performance which is the same as the Corsair VX/HX series (HX520 was docked .5 for a buzzing fan) and Seasonics own M12.

Originally posted by: mpilchfamily
There is more to it then the total +12v amperage.

If you look at the internal screen shots of the Corsair VX and the EarthWatts you'll see that they're nearly identical. The main differences are the fans and capacitors. Antec uses an 80mm fan, a Nippon Chem-icon 85°C for the single primary, and OST 105°C on the secondary side. Corsair uses a 120mm fan, a Hitachi 105°C on the primary, and Nippon Chem-icon 105°C on the secondary. In regards to warranty the EarthWatts offers a 3 yr. and Corsair offers a 5 yr. With all of that in mind the Corsair VX series edges out the EarthWatts in terms of build quality and warranty.

The EarthWatts 500 would have no trouble powering a C2Q + 8800GTX/2900XT. It also comes standard w/ 2 PCIe connectors. Both the EA-500 and VX450 are $80 @ Newegg.

Food for thought:

EarthWatts 380W powering a C2D E6600 @ 3.6GHz + 8800GTX. "How Much Power Do You Really Need For Your PC? Yet Another Experiment"

 

[mpilchfamily]

OK cool. I'll have to check the EW's review then. I've been looking into the VX latly and was thinking about picking one up.

 

[mpilchfamily]

Well i've looked over the EW and the VX. If it where a choice between the 450W VX and the 500W EW then i'd choose the VX. As John said they are virtually the same on the inside. But the sleaved wires and the black case of the VX swades me over to the Corsair side. Heck they both cost the same.

 

[EarthBoy]

haha.. yes i have looked at the EarthWatts PSU and others in the $80 price range. i chose the Corsair mainly because of its quiteness. i was led to believe that this PSU is unaudible other than the sound of air pushed out of the PSU, which is pretty impressive if u ask me.

also i do game on 1600x1200 and am considering the GTS320. i made this thread becuz i was confused w/ the 2900XT power requirement.

since the VX450 doesnt have a 8 pin i guess i wouldnt be OCing if i get a 2900XT?