GPU, Crossfire and PSU Questions.

[Fuerian]

I am not sure if this belongs in Graphics or in System, but here is my question.

I am running a 8800GTS and am looking to upgrade. I've been looking at Radeon 5770s that i wish to Crossfire. Right now i only run a 650W PSU and I dont wish to buy a pricier, more powerful PSU. Instead I am looking at a Supplimentry PSU to power BOTH Radeon 5770s but i dont know what kind of power both cards togather would run. And if this little PSU can handle it. The ad says its Maximum power is 450W at 85% efficency. It dosent have any information on Amperage.

Can 450W dedicated only to the two 5770s power them all on its own?

Is it worth Crossfiring 2 5770s togater? Or just spending that money on a single, more powerful card?

Here is a link to the Suppliment PSU for those who want to view it.

http://www.newegg.com/Product/Product.aspx?Item=17-104-054&SortField=0&SummaryType=0&Pagesize=10&PurchaseMark=&SelectedRating=-1&VideoOnlyMark=False&VendorMark=&IsFeedbackTab=true&Page=4

This is my first true computer build and I'm not too familiar with CrossFire and the Power consumption/requirements of all the various components. Any help would be appreciated.

 

[rolli59]

With a 650 watt (quality) PSU you would not need a supplementary PSU to run 2 x HD5770 in crossfire. I suggest rather going with a HD6850 or HD6870 single card with a possible future upgrade to a crossfire setup that would still run fine on a quality 650 watt PSU.

 

[Fuerian]

Really? I figured my other computer parts would use up enough power to warrent an upgrade. I was always told i needed alot more power than 650W. I'm not really sure of the quality of my PSU, i dont have the box anymore so i cant remember what brand it is.

The system im running currently is:
AMD Athalon X3 425 2.7Gh
Geforce 8800GTS
2GB DDR3 1333 RAM (Want to upgrade to 4GB)
1 HDD
2DVD Drives

I could add A much more modern card like those and still keep my 650W?

 

[rolli59]

Take a look at the power consumption charts in this link http://www.anandtech.com/show/4061/amds-radeon-hd-6970-radeon-hd-6950/24 even HD6970 would run in CF on a quality 650 watt PSU.

 

[Fuerian]

Not sure if im reading those right or not. But what your saying is that under load, my 650 watt can run Cross Fired 6850s? If i dont need a bigger/supplimentary PSU i can get two of those cards right away once christmas passes. Sorry if i sound a bit retarded. Been awake for a long time. I always thought 650W was weak for newer cards.

 

[rolli59]

A HD6850 CF will according to the charts pull 423 watts total system load running Furmark which is more than you will see in normal use. If your PSU has for example 35 amps on the combined +12 volt rail that would equal 420watts and be just fine for a setup like that.

 

[Fuerian]

Ahh. Again, i dont know the amps of my PSU. Just that it was a modestly priced 650W PSU.

 

[rolli59]

The amps should be on a sticker on the PSU it self take a look inside the case and you should find a sticker like this http://www.newegg.com/Product/ImageGallery.aspx?CurImage=17-371-015-S01&SCList=17-371-015-S01%2c17-371-015-S02%2c17-371-015-S03%2c17-371-015-S04%2c17-371-015-S05%2c17-371-015-S06%2c17-371-015-S07%2c17-371-015-S08%2c17-371-015-S09&S7ImageFlag=2&Item=N82E16817371015&Depa=0&WaterMark=1&Description=Antec%20EarthWatts%20EA650%20650W%20Continuous%20Power%20ATX12V%20Ver.2.2%20%2f%20EPS12V%20version%202.91%20SLI%20Certified%20CrossFire%20Ready%2080%20PLUS%20Certified%20%20Active%20PFC%20%22compatible%20with%20Core%20i7%2fCore%20i5%22%20Power%20Supply

 

[Fuerian]

Ahh. I'd have to pull out my computer and open it. But, how many Amps would be necessary to run two 6850s? 35 could run two? Or just one?

 

[rolli59]

If the PSU has 33 or more Amps on the combined +12 volt rail it should be able to handle 2 cards.
If you know the name and type of PSU we can look it up on the web.