Graphics 1 5970 or 2 5870's? (and power to drive them)

I'm in the middle of building my dream pc after saving up for a good long while. Overclocked i7 930, ssd to be determined, 6 gb ram, and a Seasonic X-750 for the psu. Also just got a dell 2711 monitor with a native res of 2560 x 1440 so now I need to purchase some serious graphical horsepower. I have come down to either a single 5970 vapor x(850 mhz, 4GB) or 2 5870 vapor x's (850 mhz, 2GB each), and was wondering which was the better buy. The price is similar but right now it looks like the 2 5870's would come in about $100 cheaper. So...

-I saw somewhere that 2 cards in x-fire is better because they each get the full 16 lanes, but I don't know if that makes a difference.

-I don't know if driver wise a single card, even with duel gpu's is more stable, or if it shows up as x-fire just the same.

-Power and heat wise I'm guessing that the 5970 would run on a little less juice, but I may be mistaken. I'm not too worried about heat because they are the vapor x models, but power is a concern. With this setup I won't have much headroom with my 750 watt psu. I'm pretty sure this psu is good to its rated power, as it is a quality unit, but does anyone think I will have a problem with power, and would choosing either graphics setup over the other make a difference?

-I plan to overclock the card or cards either way up to the clocks the toxic editions come at, would either setup be more conducive to overclocking?

So, which way should I go. All things equal I would go for the cheaper option, but I'm spending a grand on graphics cards (which hurts me to think about, but I've been working 11 hour days for the past 6 weeks to finance this), so I will go with the better option if there is a difference.
Thanks

-Joe-

 

from the benchmarks ive seen it looks as the 5870 xfrie has the edge, my guess is a good quality 750w psu would be ok

 

You can run duel 5870s on a decent 600 watt pse if not overclocking anything as a friend of mine does it no issues at all

5870s in crossfire are faster than the 5970, so 750 with overclocked CPU should be good enough

recomend seasonic psu

5970 is a waste of money for the price if duel 5870 vapor x is cheaper makes it look even worse

anybody with a crossfire board should use duel cards vs duel gpu on a single card alot less driver related issues

 

I thought the 5970's still relied on good crossfire driver support?

In terms of raw grunt; two 5870's are more powerful as the 5970 is two 5850's stuck together.

Two 5870's should be cooler than the 5970 so should allow better overclocks; providing there's decent airflow.

If it was my money; it'd be on the two 5870's.

 

Oh and get the Voltage tweak Asus ones that allow higher core voltages for better overclocking.

 

Performance terms yes, technically no (its two fully fledged Cypress cores running at HD5850 clocks to meet the 300w power envelope of the PCI-E spec).

In the ops case (who is looking at the Vapour-X HD5970 4GB model) it is 2 Cypress cores running at full speed (850/4800) and thus will perform within ~5% of 2 x HD5870 2GB in CF.

Given that the op has mentioned he can get 2 x HD5870 2GB cards for $100 less than the HD5970 the choice is simple; HD5870's all the way.

In general the HD5870's will be cooler running and should overclock a bit further. They may however be slightly louder (there are two of them afterall) and will possibly use more power although given the system specs I doubt this will be a major issue.

 

Guru 3d benches show a good case for saving cash and getting 2x GTX470 for SLI rather than HD5870cf..substantually cheaper route.

Seems to keep up with xfire HD5870 and even surpass it in some games. (from these results)
http://www.guru3d.com/article/inno3d-geforce-gtx-480-ichill-black-series-review/1

 

Cards from any manufacturer are capable of voltage adjustments through software. Just buy whichever is the cheapest/best warranty.

 

Or do what I intend to do. Buy a 5970 and then add a 5870 later on

 

Thanks

Looks like for once the cheaper option and better option are the same. 2 5870's it is, and I will overclock them. It looks like with the vapor x cooler people have had no problem getting a fair overclock with them. The seasonic psu is the one I have btw. Thanks for the help. Any ssd suggestions for around 300? Right now I'm probably going with the 128 nova the buyers guide suggested.

-Joe-

 

Don't worry about power consumption. I come to realise that after getting a fan controller that measures power draw of my computer.

When not overclocked an i7 920 + 5970 stuggles to break 250W most of the time and never breaks 300W. When overclocked to 4ghz CPU and 1000/1300 GPU, it stuggles to break 550W and never goes beyond 600W.

In terms of power consumption the 5970 uses less energy than two 5870s at load and idle which wouldn't impact performance but you might not like a computer that is producing so much heat. I personally think my computer is a space heater when overclocked, not really proud of it.

 

intel x25- 160gb ssd for that price.
Did you not concider 2x GTX470 instead of 2x HD5870.
Just as fast and even faster than the xfire, but £70 cheaper. (£130 cheaper than getting the ones you are looking at) and with physx etc

Power consumtion and heat will be more than the HD5870 xfire solution though.

 

Even just with the overclocked i7 the thing produces some heat. Although after optimizing the overclock to run on less voltage it's better. I went to 4.1 ghz, then dropped all the voltages as low as possible to be 24 hour prime stable. With the 2 cards it's going to be crazy, especially in a small dorm room.

I'll take a look at that drive, is it about as fast as the nova?

I haven't really considered the current nvidia cards because I'm just not willing to put up with the noise and heat they put out. Even the 2 5870s would be to much for me without the vapor x cooler. I also plan to hackintosh this, so when the new mac pros come out thy are more likely to have ati 5800 series cards, so I could use one of these cards. It would also put me even closer to 750 watts.

-Joe-

 

+1 I never knew that. Get two 470's

 

Hmzz the results from different places show it differently.

Hexus, for example shows a much closer speed - in all their benchmarks (with the FPS values summed) across all games GTX470 SLI only gives a 4fps advantage. Remember that that is across 4 different games, so you aren't seeing much, on average a 1fps advantage in each game at 1920x1080. The 5870 cf rig is faster at ultra-high resolutions.

Furthermore, it's much noisier - the subjective analysis done by Hexus (not all noises are equal and that) clearly rates the 470s as making a lot more noise whilst running hotter (and that's not even talking about power consumption).

Price wise, since nVidia finally wised up and dropped their prices, 470s are more attractive than they were, but the price difference is only £10 now depending on where you shop.

(I'm ignoring the ScanFX one since the warranty is awful).

http://www.hexus.net/content/item.php?item=24263

 

Two years is terrible?
Fair enough on the noise though, that's the reason i don't own a 480 right now.

 

What I'm saying is that RMAing to Scan often does not lead to good results. If they don't have the right card in stock (ie if the line has been discontinued) they often just give you a partial refund. I've seen people RMA 9-month old £130 4870s and get refunded £70, which to me just seems cheap on Scan's part.

 

I remember moans about that a couple years ago.
They didn't change policy?

 

http://forums.hexus.net/scan-care-hexus-after-sales-support/187579-xfx-warranty-issue.html
Nope

9800gx2, and they won't even give him enough to get a GTX260. Pitiful

 

Single Fermi 470/80vs a comparable single 58xx is generaly a win for ATI, deffinately on price/performance and sometimes even pure performance can an ATI card can beat a more expensive Fermi. But SLI scales much better in general than Xfire, so for dual and higher GPU setups Nvidia is perfectly viable. Though I do like my PCs quiet so for now Fermi is a pass for me regardless.