Powering a ATI 5870

[Guest]

Hello,

I have a dell XPS 8100. The system came with a ATI 8770, however the video card didn't work and they sent me a ATI 8870 to replace it (they were out of 8770s). Now I was excited to get a better card, but when the guy came to install it we discoverd the card requires 2 6 pin power connectors and I only have one. The service guy told me to just buy a 6 pin single to 6 pin double connector at Frys. However, when I went to Fry's they told me that they didn't have such a thing, and that it probably won't be safe to power this this way if they did. Does anyone here have any suggestions on how to power this card. Of course I can complain to Dell again, however I'm trying to avoid this since this will likely end up with me getting downgraded to a 8770 again.

 

[WR2]

What you want is a Molex 4 pin to 6 pin PCI-e adapter. Attach the 4 pin parts to spare 4pin molex connectors from the PSU and plug the 6 pin connector into the video card. 8" 6-Pin PCI Express (PCI-E) Power Adapter Cable - Adapts Dual Molex Power to PCI-Express Power Connector

 

[WR2]

What size power supply does your XPS 8100 have installed? There might be an issue with the amount of power it takes to power a 5870 vs a 5770.

 

[maudjuly]

THe PSU is the standard dell xps 8100 350W. Will that be a problem? Also, the best I can tell, there isn't any free Molex 4 pin connections. In fact, expect for extra connectors on hard drive and CD cables there aren't any free connectors.

 

[maudjuly]

And, of course, Above I meant 5870 vs a 5770 not 8870 and 8770.

 

[WR2]

Im starting to think it's a problem. From what I see in the Dell forums Im not sure that power supply can handle the 5870.
It's easily worth a call to them to confirm it's OK.
And ask them about how to connect it up! I can't find anything on a 6 pin to 6pin double. And like Fry's I think one of those would be a bad idea.

 

[WR2]

That 401watts load on the 5870 is measured at the wall socket and it's not the same as what the PC is using.
Still its far far to close to the upper limit of what a 350W PSU can provide.
Even if it could supply enough power it would be pushed to near its limit - never a good thing for a PSU.

 

[maudjuly]

Thanks. I noticed that the ATI website says the 5870 requires a 500w psu. But then again, the ATI website also says that the 5770 requies a 450w psu and dell sells these in a machine with a 350w psu. I read elsewhere that dell underclocks the cards to do this (Which makes me a bit scared since I plan to run 3 displays off the card -- which is why a bought the machine in the first place -- and I hear to get good performance here that people have needed to overclock the cards).

It seems I need to talk to Dell again. I'm fearful that they'll trade my 4870 back for a 4770 now. Of course, this is what I bought in the first place, but I thought it was somewhat fair compensation consider the new machine I bought 2.5 weeks ago hasn't had a minute of functionality since I opened the box. I almost could sell the 5870 on ebay, buy a 5770 and get a nice partial refund on the system -- although I'm sure that would screw up something.

 

[WR2]

I know Dell has a reputation for under-rating their PSUs. But I think its a stretch to think a 350W PSU would be that much under rated.
-> Before you call surf around the Dell support forums and see if anyone else is running a 5870 on that 350W PSU. If they do it... you can to.
It would be a lot cheaper for Dell to ship you one of those Dell '6pin single - 6pin double adapters' (if there is one) than a whole other video card swap out.

 

[maudjuly]

I haven't been able to find anyone running a 5870 on a 350w dell psu.

Here's another question. If I understand it correctly I should be able to replace the psu without voiding the dell warranty (see: http://support.dell.com/support/topics/global.aspx/support/dsn/en/document?docid=AB69975A7B924478B9A32CDE462E70D1&c=us&l=en&s=gen).

I guess I'd prefer to do this before I trade back my 5870 for a 5770, if it isn't too costly. What would be a good psu option for this? It needs to fit in a xps 8100 case (elsewhere I've read that some generic psus will fit this case -- unlike other dell models).

 

[WR2]

Thats how I read that policy. Warranty remains good.
I think the PSU swap gets you the best bang for the buck.
Say $75 for a new PSU vs the $150 5770 -> $400 5870
That's a value added $175 bonus to you.

OCZ StealthXStream OCZ600SXS 600W $75 with $15 'rebate card' *free shipping*
CORSAIR CMPSU-650TX 650W $90 plus $20 'rebate card' *free shipping*
OCZ ModXStream Pro OCZ700MXSP 700W $90 plus $25 'rebate card' *free shipping*