ATi 4870 X2 (R700) previews thread

[SSChevy2001]

Originally posted by: taltamir

Originally posted by: uclaLabrat

Originally posted by: taltamir
that is a lot of watts to take from the wall... i am thinking a 700 or 750 watt PSU would be the min for that card.

Are you banking on 50% efficiency or what?

Actually the "efficiency" rating of the PSU has the opposite factor here. A 50% efficient PSU Would waste half the power it draws. So drawing 500 watt at the wall means its only providing 250 watts to the PC, which would be a specific percent of what it is rated for. Ofcourse, a 50% efficient PSU will be utter crap so it will be able to provide even a smaller percentage of its rated capacity.
Firstly companies flat out LIE on these, then there is the "peak power draw" instead of "sustained power draw without frying"... Quality sellers use the sustained figure, crap ones use peak.

Also, no PSU can provide the figure it is rated for, firstly the figure is if ALL the various voltage rails are maxed out, bur realistically your system will be overburdened on one area, like the V12 rail for example. Depending on your components. It is impossible to have components take EXACTLY the amount of power your PSU can push on the 3v, 5v, and 12v rails1 and 2 (and even 3 and 4) all at once and perfectly balanced.

I would assume he was talking about 50% usage, not efficency. HardOCP was able to run 2 4870x2 in Crossfire X with only a 800watt PSU. So your min requirements PSU are a little high. Even tomshardware specs showed 650watt PSU, which is a little high because of some low quality PSU.

The biggest problem is not how much this card draws on load, but the idle power. That even a bigger problem than microstutter, as far as I'm concerned.

 

[taltamir]

chevy... my min requirements estimates were 700 or 750 watts... which is very close to 650watts... I am also account for low quality PSUs. it takes 450 watt at the wall, that means on a high end 80% efficient PSU that it delivers 450 x 0.8 = 360 watts to the computer. yet it requires a 650watt PSU, maybe 600 watt if it is high quality, to deliver those 360 watts in a stable consistent manner.

Min power draw and microstutter are ALSO issues.

 

[SSChevy2001]

Originally posted by: taltamir
chevy... my min requirements estimates were 700 or 750 watts... which is very close to 650watts... I am also account for low quality PSUs. it takes 450 watt at the wall, that means on a high end 80% efficient PSU that it delivers 450 x 0.8 = 360 watts to the computer. yet it requires a 650watt PSU, maybe 600 watt if it is high quality, to deliver those 360 watts in a stable consistent manner.

Min power draw and microstutter are ALSO issues.

Not to be a pain, but high quality PSU delivers the full rated power continuous, and have a higher peak wattage. ( 650w PSU = 650w continuous - peak in the 700-750w range ). Still way over that 360watt.

 

[taltamir]

they deliver it on all the rails combined
The chances of you maxing out each and every line / rail of the PSU at the same time is astronomically low.

 

[SSChevy2001]

Originally posted by: taltamir
they deliver it on all the rails combined
The chances of you maxing out each and every line / rail of the PSU at the same time is astronomically low.

My Corsair is rated for 52a / 624w on a single 12v rail. Also I would check the noise level for the PSU, which in my case 455w DC is about 26dBA, which is the max I want even though it will take more. The next level 520w DC is 30-31dBA.

 

[Nathelion]

Most high-end power supplies have higher max ratings on individual rails than they could sustain if all rails were being used at max all at once. For example, my Silverstone Zeus 750W can supply something like 700W on the 12V rials alone, but it can also supply something like 300W on the other rails combined. Obviously, the total of all that is higher than 750W. So there is a good chance that a rig can actually max out a power supply's total capacity without overburdening any specific rail.

 

[chewietobbacca]

Idle power will be fixed on the 4870X2's anyways so I don't think its a big issue. And others have covered the PSU issue.

As far as Microstutter goes, PCGH is the only one that had issus and it was with Grid, a game they didn't patch AFAIk since the recent one fixes the issue. Sampsa @ the Finnish website and XS tested before and after tests with the patch and had no issues with the most recent update. Also, no one else really tested those cards. I'm not going to bother talking about whether PCGH is negative towards Radeon cards as some users have suggested since I can't read German so I don't know context or tone of reviews or whatever to make a judgment though.

Anyways, we will seen soon enough how the card does when more users begin actual use rather than the spattering of tests.

 

[bryanW1995]

Originally posted by: SSChevy2001

Originally posted by: taltamir
they deliver it on all the rails combined
The chances of you maxing out each and every line / rail of the PSU at the same time is astronomically low.

My Corsair is rated for 52a / 624w on a single 12v rail. Also I would check the noise level for the PSU, which in my case 455w DC is about 26dBA, which is the max I want even though it will take more. The next level 520w DC is 30-31dBA.

you must have the TX 650. my hx 620 has 51a on the single 12v rail and would likewise be more than sufficient for a 4870x2. corsair is very conservative with their ratings, however, as most manufacturers would list both of our psu's as 700w+.

 

[BFG10K]

Originally posted by: chewietobbacca

As far as Microstutter goes, PCGH is the only one that had issus and it was with Grid, a game they didn't patch AFAIk since the recent one fixes the issue.

Sorry, no, that's incorrect. Let's quote them again and bold the games they mentioned:

In 3DMark Vantage the first bumpy situations appear in the Extreme preset. Race Driver Grid delivers microstuttering if the frame rate drops below 50 - the subjective frame rate lies between 30 and 40. NfS Carbon and Half-Life 2 (dt.) produce microstuttering at frame rates below 40 fps. Playing at this frame rate feels like it does on a single GPU that delivers about 20 fps.

I fail to see why people continually try to pretend the issue doesn't exist.

Sampsa @ the Finnish website and XS tested before and after tests with the patch and had no issues with the most recent update.

Sampsa also tested with a higher framerate, and therein lies the problem.

 

[QuadDamage2k]

http://www.zipzoomfly.com/jsp/...p?ProductCode=10008893

$240 bucks

buy 2 of them

 

[SSChevy2001]

@QuadDamage2k

The 4870x2 has it's advantages over a pair of single cards.

Crossfire X
Better performance
2GB ( only 1GB usable )
Lower idle and load power consumption
Less $

 

[MichaelD]

Originally posted by: SSChevy2001
@QuadDamage2k

The 4870x2 has it's advantages over a pair of single cards.

Crossfire X
Better performance
2GB ( only 1GB usable )
Lower idle and load power consumption
Less $

Why is only 1GB usable? OS 4GB total RAM limitation? I'm thinking about an X2 over a normal 4870. Thinking about being the operational phrase here; don't really want to have to buy a new PS too. But if the performance is going to be THAT good without the probably Crossfire headaches (and losing a PCI-E slot) than I'm going for it.

 

[unr3al]

lolz @ nRollo

ATi definitely caught nV with their pants down this round. And about time too; ATi hasn't had the performance crown since the X1950XTX!

The power consumption is an interesting point as well; over 100W less than SLi GTX280 and sometimes outperforming? Wow. And it also (understandably, but still) draws less power than CF 4870s. Not too shabby...

 

[SSChevy2001]

Originally posted by: MichaelD
Why is only 1GB usable? OS 4GB total RAM limitation? I'm thinking about an X2 over a normal 4870. Thinking about being the operational phrase here; don't really want to have to buy a new PS too. But if the performance is going to be THAT good without the probably Crossfire headaches (and losing a PCI-E slot) than I'm going for it.

No it has to do with the design. Each GPU only has 1GB to work with instead of sharing the whole 2GB. I could be wrong but the same data is copied each 1GB, making only 1GB usable.

 

[MichaelD]

Originally posted by: SSChevy2001

Originally posted by: MichaelD
Why is only 1GB usable? OS 4GB total RAM limitation? I'm thinking about an X2 over a normal 4870. Thinking about being the operational phrase here; don't really want to have to buy a new PS too. But if the performance is going to be THAT good without the probably Crossfire headaches (and losing a PCI-E slot) than I'm going for it.

No it has to do with the design. Each GPU only has 1GB to work with instead of sharing the whole 2GB. I could be wrong but the same data is copied each 1GB, making only 1GB usable.

Thanks. I didn't know that.

 

[Aberforth]

here's another:http://www.bjorn3d.com/read.php?cID=1317&pageID=5157

 

[thilanliyan]

So does the Crossfire GPU-to-GPU link actually do anything?

 

[MagicConch]

I have a question about this videocard. Does the motherboard need to support Crossfire if you are using this card (w/ no plans to add another)? Since the bridge is on the card itself I would assume it doesn't and the level of support (8x vs 16x) also would have no impact on performance of this card by itself.

 

[thilanliyan]

Originally posted by: MagicConch
I have a question about this videocard. Does the motherboard need to support Crossfire if you are using this card (w/ no plans to add another)? Since the bridge is on the card itself I would assume it doesn't and the level of support (8x vs 16x) also would have no impact on performance of this card by itself.

No need for a CF m/b but it would be best if you have one with a PCI-e 2.0 x16 slot.

 

[bryanW1995]

no need for xfire support on the mobo. should be no benefit to you having it.

edit: whoops, I need to hit "refresh" more often...

 

[Calculator83]

I"M Soooo SOLD.. OMG where are ze preorders.

 

[Eluros]

Hey, all!

This article claims to prove that the 4870x2 has a significant Microstuttering problem. Does this sound accurate? I really don't know much about the issue.

http://www.pcgameshardware.com...the_Radeon_HD_4870_X2/

 

[Nurn]

I dunno about "significant"....

"But not everyone notices the problem. A lot of people don't even recognize the micro stuttering and therefore don't see any differences to normal situations. The trick is not to see that the game stutters but how it does."

I run a couple of 3870's in Crossfire, and everything looks good to me.

 

[Calculator83]

Originally posted by: Eluros
Hey, all!

This article claims to prove that the 4870x2 has a significant Microstuttering problem. Does this sound accurate? I really don't know much about the issue.

http://www.pcgameshardware.com...the_Radeon_HD_4870_X2/

micro-stuttering = slightly worse than average frame dip. Thats all you need to know. And no one really cares.

 

[HumblePie]

Almost August.... just waiting to be able to hit that, "add to cart" button on some site.