2 X 4850 and you need 1200W???

[Mango1970]

Did I read that correctly in Anand's review of the 4850? That going crossfire their original 1000W PS was not cutting it. Are we mad?? Was there some sort of issue there?

Reason I ask is that on my eVGA 680i with 3 500GB drives, 1 36 Raptor, wireless card, 6 fans, 4 GB or RAM, a e6850 oc'ed to 3.7 Ghz, and now finally 2 eVGA 8800GTX in SLI, my PC&C 750 silencer is totally fine. What gives with these new cards? Are we not supposed to be seeing faster and more efficient cards with new technology?

 

[bryanW1995]

they had a problem with their psu. it couldn't run one gtx 280 stable, either.

 

[GlacierFreeze]

It was probably failing and no you don't need that much...

 

[MarcVenice]

750w is all you need for dual HD4850's. And that might be overkill, 650w might actually cut it to, with a big enough margin to keep things safe.

 

[Mucker]

My Enhance built Antec TPQ-850 doesn't blink with my 4850's in CF. My overclocked Q6600, CF system with Raid idles about 270 (measured by my APC UPS) + 110 watts with cpu fully loaded + estimated 220 watts with VC's fully loaded = estimated 600 watts maximum consumed for the system. What is most important is how much amperage your psu carries on the 12v line. The TPQ-850 is not lacking 12v amps.

A thing to remember is that the 4850 does not pull any more juice than an 8800GT or 3870, all pull around 110 watts peak.

 

[solog]

Originally posted by: Mango1970
Did I read that correctly in Anand's review of the 4850? That going crossfire their original 1000W PS was not cutting it. Are we mad?? Was there some sort of issue there?

They did also state that total system draw (under load) was 336 watts (for 4850 Crossfire setup). Maybe they should have explained that neither a 1000 watt nor a 1200 watt psu is necessary. Maybe they did and I just missed it.

Not everyone has the same level of computer knowledge that reads his site. Maybe the full review will use a different power supply or explain why they are doing what they are doing.

 

[Mango1970]

Ahh thanks folks. For a bit there I was thinking that with my 8800GTX in SLI I was killing my system. Good to hear it was simply an anomaly.


thanks

 

[monavie]

i am running core 2 with 2 gig memory @ 4.1 ghz, dvd , 2x 4850 plus 2 hd;'s but load of fans ..650 wat working fine..prolly towards its max but 650 -750 wat should be good.

 

[HOOfan 1]

Derek Wilson had this to say in the comments of the HD4850 article.

Originally posted by: Derek Wilson
4850 crossfire and up and gt200 sli and up will absolutlely massive ammounts of power to run. we would be the first to say that a 1kW PSU was enough if it were -- but it is not.

Which is just HOGWASH...it makes me doubt that he has any idea what he is talking about where PSUs are concerned. They were obviously having a problem with that particular PSU.

Jonnyguru has stated that the GTX280 has some sort of power defect that has nothing to do with the PSU not providing enough power, and assumes it will be fixed with a BIOS flash.

 

[BigMoosey74]

There we go. I was actually wondering this too. Anand made it sound like the PSU wasn't able to handle xfire but it didn't make sense seeing the total system draw was under 400W.

"Our 1000W OCZ EliteXStream wasn't always enough for the dual-GPU setup and in Call of Duty 4 our system rebooted in the middle of our test at 2560 x 1600"

A little misleading....or like Hoofan says...mislead?

 

[dennilfloss]

Crap now I wonder if my Enermax Infiniti 720w could handle a 4870X2.

http://www.virtual-hideout.net...initi_720w/index.shtml

 

[VirtualLarry]

I'm personally going with an EarthWatts 650W PSU, for my Q6600s (OCed) and a pair of 4850s CFed. (That is, if I decide to CF. I have two rigs and two graphics cards, still trying to decide on whether or not to CF or not.)

 

[Pollock]

Hmm, 600W OCZ + 4850 CF?

 

[HumblePie]

I have the Coolermaster 850w real power pro handling a overclocked q9450, 4GB of ram and DFI x38 board, 4x raptors, 2x samsung f1's, SB x-FI card, and around 8x 120mm fans all with no problem.

Been playing Mass Effect all weekend long (picked it up along with the 2 cards from Bestbuy on friday) and been loving it!

 

[BigMoosey74]

If Anand's total system draw for 2x4850 was 335W there is no way a 600W+ PSU is not enough for xfire 4850 unless you are running a boatload of disks and are filling up USB ports with your USB coffee maker and what not. Someone confirm or correct me on this but I think the ATI recommended PSU for xfire 4850 is 550W and those are usually even over estimates.

 

[solog]

Derek Wilson posted this also:


RE: Power Supplies by DerekWilson, 3 days ago
all these tests have been done at Anand's place and at-the-wall power should not be a problem for any of these recent articles.

we did have problems with our 1kW thermaltake and our 1kW ocz PSUs with the GTX 280 in SLI. we couldn't get through a crysis run.

in testing 4850 crossfire, the 1kW ocz power supply (elite xtreme) failed during call of duty.

we had no problems with the 1200 W pcp&c turbo cool PSU we now have installed.

our peak power numbers were shown using one of 3dmarks GPU only feature tests. this is in order to isolate GPU power as much as possible for comparison purposes between different graphics cards.

power draw at the wall will be MUCH larger when playing an actual game. this is because the CPU will be under load and system memory will likely be hit harder as well. we will also see the hard disk active as well.

i do apologize for not explaining it further. knowing what app we used to test power would probably have done enought to explain why the PSU crashed under game tests but not under our power test with a 1kW PSU ...

4850 crossfire and up and gt200 sli and up will absolutlely massive ammounts of power to run. we would be the first to say that a 1kW PSU was enough if it were -- but it is not.


Now I don't know the powerdraw of his cpu, but 4x1GB of DDR2 should be less than 25 watts I believe and his one hard drive should be less than 20 watts. There is a big gap between that and one thousand.

 

[solog]

Originally posted by: BigMoosey74Someone confirm or correct me on this but I think the ATI recommended PSU for xfire 4850 is 550W and those are usually even over estimates.

Don't see anything over at ATI. Visiontek recommends 450W PSU for one and 550W for Crossfire in dual mode

 

[GlacierFreeze]

Originally posted by: solog
Derek Wilson posted this also:


RE: Power Supplies by DerekWilson, 3 days ago

4850 crossfire and up and gt200 sli and up will absolutlely massive ammounts of power to run. we would be the first to say that a 1kW PSU was enough if it were -- but it is not.

That's a load of BS. 1k isn't enough my ass.

 

[idiotekniQues]

im thinkin my corsair 620HX might not be able to handle two 4850's in CF down the road?

 

[Mucker]

Originally posted by: BigMoosey74
If Anand's total system draw for 2x4850 was 335W there is no way a 600W+ PSU is not enough for xfire 4850 unless you are running a boatload of disks and are filling up USB ports with your USB coffee maker and what not. Someone confirm or correct me on this but I think the ATI recommended PSU for xfire 4850 is 550W and those are usually even over estimates.

It could be close. Personally, I like a safety margin. If a system draws 600 watts, I go with an 800 watt psu. Don't like running them near the ragged edge. Also the efficiency will be better at about 3/4 of the max load on most psu's.

My system has the potential to pull 600 watts, assuming everything is maxed out 100%.

 

[HOOfan 1]

Just to further refute Derek's claim

The HD4850 uses a single 6 pin PCI-E connector.

The card can draw no more than 75W from the PCI-E 16x slot itself and no more than 75W from the 6pin connector.

That is no more than 150W total for a single card....300W for two in tandem.

They were trying to claim that an OCZ EliteXstream with a single 12V rail capable of delivering 960W was not capable of running that system.

Even if the cards were pulling every bit of that 300W (which they most certainly would not be) Then we have to assume that the rest of the components were pulling more than either 660 Watts of 12V or 900 Watts all together?

Again I say HOGWASH.

 

[MagicBoyUK]

The box for my Sapphire card states 450W for a single card and 550W in crossfire.

 

[Nathelion]

There was definitely something up with their PSUs, or possibly their wall power. There is just NO WAY that a properly functioning 1000W PSU wouldn't cut it.

 

[ChronoReverse]

Originally posted by: HOOfan 1
Just to further refute Derek's claim

The HD4850 uses a single 6 pin PCI-E connector.

The card can draw no more than 75W from the PCI-E 16x slot itself and no more than 75W from the 6pin connector.

That is no more than 150W total for a single card....300W for two in tandem.

They were trying to claim that an OCZ EliteXstream with a single 12V rail capable of delivering 960W was not capable of running that system.

Even if the cards were pulling every bit of that 300W (which they most certainly would not be) Then we have to assume that the rest of the components were pulling more than either 660 Watts of 12V or 900 Watts all together?

Again I say HOGWASH.

++

Honestly, I was quite disappointed in AT that they didn't test another PSU with similar power (or lower) before declaring such a problem.

 

[BigMoosey74]

Nice posts everyone. There were no system specs listed so I am not going to get too bent out of shape over this. On Wed some bona fide information will come out (full reviews). Since their PSU died there is NO evidence supporting their statement that a 1KW PSU isn't enough for xfire.

I doubt Anand reads the forums but it would be nice to have them extrapolate on this power issue since their preview article was not accurate and has left a lot of people in a state of confusion.