Which will perform better?

[pcpro178]

Which can I expect to perform better?

Two (2) of these:
XFX HD-677X-ZNFC Radeon HD 6770 1GB 128-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150560&Tpk=XFX%20Radeon%20HD%206770%20HD-677X-ZNFC%20Video%20Card

Or, one (1) of these:
XFX HD-687X-CNFC Radeon HD 6870 2GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150563&Tpk=XFX%20Radeon%20HD%206870%20HD-687X-CNFC%20Video%20Card

My system has these three monitors that I would like to use for an Eyefinity gaming experience:

Asus ML228H 21.5" 1920X1080 2ms Full HD LED BackLight LED Monitor Slim Design 250 cd/m2 10,000,000 :1 (ASCR)
http://www.newegg.com/Product/Product.aspx?Item=N82E16824236099

APPROXIMATE PURCHASE DATE: Not applicable.
BUDGET RANGE: As little as possible, obviously.
USAGE FROM MOST TO LEAST IMPORTANT: Gaming (Sword of the Stars II, Unreal Tournament), Office, Internet
CURRENT GPU AND POWER SUPPLY: Not applicable (new system)
OTHER RELEVANT SYSTEM SPECS: AMD CPU, probably ASUS or Gigabyte motherboard
PREFERRED WEBSITE(S) FOR PARTS: Newegg.com
PARTS PREFERENCES: AMD or ATI
OVERCLOCKING: No
SLI OR CROSSFIRE: Maybe (What do you think?)
MONITOR RESOLUTION: 1920x1080 (three monitors)

 

[rolli59]

When crossfire is supported the 2x6770 will be more powerful.

 

[geekapproved]

I don't get the choices.

1 $225 card or 2 $125 card.

Why not 1 $250 card?

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=40000048%20600007782&IsNodeId=1&Description=6950&bop=And&Order=PRICE&PageSize=20

I'd go with this one:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814150550

 

[GreenDutchAlien]

I don't get the choices.

1 $225 card or 2 $125 card.

Why not 1 $250 card?

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=40000048%20600007782&IsNodeId=1&Description=6950&bop=And&Order=PRICE&PageSize=20

I'd go with this one:

http://www.newegg.com/Product/Product.aspx?Item=N82E16814150550

^+1

 

[pcpro178]

This is just an example. I'm trying to understand how to properly select a graphics card for my system. As far as performance is concerned, it looks like using 2 cards with half the processing power will generally win out over a single card with twice the power.

 

[rolli59]

This is just an example. I'm trying to understand how to properly select a graphics card for my system. As far as performance is concerned, it looks like using 2 cards with half the processing power will generally win out over a single card with twice the power.

Incorrect having two cards does not double the power, 90+% increase is good. A single card that is truly double the power will win over the dual card solution. You should be comparing the 2x6770 with HD6950

 

[pcpro178]

Incorrect having two cards does not double the power, 90+% increase is good. A single card that is truly double the power will win over the dual card solution. You should be comparing the 2x6770 with HD6950

Granted, but does that hold true if I want to spend no more than a given amount on graphics hardware? For example, let's say that I have $500 to spend. Would I be better off buying two $250 cards with Crossfire, or a single $500 card? For power for buck, it seems like the two-card option is better.

What it really comes down it is this. I want to drive my three monitors for an Eyefinity gaming experience. My monitors have a high resolution of 1920x1080. I do not want to spend $7000 on a graphics card. I want to get the best bang for my buck.

This is the card I'm looking at right now:

XFX HD-687X-CNFC Radeon HD 6870 2GB 256-bit GDDR5 PCI Express 2.1 x16 HDCP Ready CrossFireX Support Video Card
http://www.newegg.com/Product/Product.aspx?Item=N82E16814150563

Would I need two of these, or would one be sufficient?

 

[rolli59]

For eyefinity which makes the resolution bigger I would recommend minimum 2 x HD6850 in Crossfire so to answer your question you will need 2 cards to enjoy gaming with 3 monitor eyefinity. Then again I would recommend as here 2 x HD6950 2GB for gaming in eyefinity http://www.tomshardware.com/reviews/gaming-performance-radeon-geforce,3018-5.html

 

[jyjjy]

The least you should consider for Eyefinity gaming at that resolution is a 2gb HD 6950. If you can afford it 2 for crossfire would certainly help.

 

[Friznutz]

I would strongly recommend two 6790's for gaming. They will perform considerably better than two 6770's. At newegg.com they are selling for $99 right now. I would choose that over any of your choices.
Take the cards quick before the rebate (if you choose to use it) goes away. Even if it does, [strike]it will only cost you $4 more than the 6770's.[/strike] With free shipping it will be $7 cheaper for both.



http://www.newegg.com/Product/Product.aspx?Item=N82E16814131397

 

[geekapproved]

Keep in mind 6770's are only 128bit, not 256bit.

I would still take a single 6950 2gb over any of the choices mentioned.

 

[jyjjy]

I would strongly recommend two 6790's for gaming. They will perform considerably better than two 6770's. At newegg.com they are selling for $99 right now. I would choose that over any of your choices.
Take the cards quick before the rebate (if you choose to use it) goes away. Even if it does, [strike]it will only cost you $4 more than the 6770's.[/strike] With free shipping it will be $7 cheaper for both.

The 1gb of memory on the HD6790 is inappropriate for the large resolution(5760x1080) the OP will using. Also the rebate on those cards is limited to one per person.

 

[Friznutz]

You make no sense.
There will be the same amount of VRAM all together. And 1 screen will get a full 1gb or VRAM. If you get a 2gb each one will get about 656ghz each monitor. And who cares about the rebate that much. It will only cost you $4 more than a standard 6770. You really must read my post before saying the stuff you say.

Here it is if you still dont understand.

Monitor 1-main gaming monitor which will display center view- supply by the 1 6790 (for $120) full 1g vram being pushed to that monitor....
Monitor 2+3- Side monitors both using 1 6790 each receiving 512mb vram ($99). Those monitors will most likely not be displaying the UI and you will most likely not focus stuff on them.

2 6790's will have a combined 1600 stream processes. With 2x840mhz combined GPU speed. (monitor 1 will get a full 800 stream processes and 840mhz core speed with 1gb vram and monitor 2+3 will get 400 stream processes each, 420mhz core speed and have 512mb of VRAM each (this is all theoretically separated ratio)

if you have a 6950 you get 1408 stream processes. With only 1* 870mhz core speed (each monitor will get (theoretically) 469 steam processes and have to share 2gb of VRAM (666mb each)


Therefore making you main display, which will most likely display most of the game data, have the most amount of power.
6790 (maybe lag in 2+3 screens)
6950 (if there is lag, will be on all screens)

 

[swifty_morgan]

for eye-finity you'll need a good card with 2gig of memory..... the 6950 minimum. put 2 cards that have 1gig of memory does NOT = 2gigs and will be worthless. This is big card territory. I have my doubts about that 68 series you posted. Different architecture than the 6900 series. Cross-firing 2 2gig6900 series cards should be the ticket if you can afford it.

 

[Friznutz]

http://forums.anandtech.com/showthread.php?t=2157093

In every review 6790 Crossfire is better than a 6950 1gb and 2gb. And why would you say cross-firing two 6900's. Why dont you read what he says again and not even recommend things that he did not ask for.


EX. If you ask a car dealer for a Honda Accord and he says "No. What you want is a Ferrari. Can you afford it?"
I would say "Um.... Are you an idiot? I am here looking for a well priced car that will get me places. Not something I didn't ask for!"
Then I would leave

I have noticed a ton of stupid people say that kind of stuff. Like ex.
"I am looking for a $100 video card that can run games."
Answer-"If you can get like a. 6990 get that. It runs all games at max settings."
I have seen stuff like that and it is extremely stupid

 

[swifty_morgan]

your immaturity and lack of knowledge about computer hardware is showing through.

 

[photonboy]

My two cents:

1) SLI and Crossfire. STAY AWAY! There are micro-stutter issues. Read the recent Tomshardware article. There are other issues as well.

2) Three monitors:
Read the details of hooking them up carefully to ensure your monitors have the required inputs. I'm not sure if you still require a DisplayPort to get the third monitor working.

3) I'd probably recommend gaming on your main screen but that's your choice and it will depend on if your gaming card can support three screens fast enough. I simply don't like the BEZEL issue, but three is much better than two because with two screens the bezels are right in the middle.

Example of recommended cards:
HD6950 2GB

HMMMM....

I have been investigating whether the internal DUAL GRAPHICS of this card has the same micro-stutter issues as Crossfiring two single-GPU cards and couldn't find any answers. I found crossfire of two HD6950's but that's FOUR GPU's.

Based on your needs I'd have to go with this card. I simply can't find a better solution for the price. If I recommend a similarly-performing single-GPU AMD card then it would require DisplayPort for the third monitor.

to be clear on cables:
1) 4x native, and
2) up to 6x with Displayport

That's a double (two cards integrated basically) of the previous 2xDVI + 1xDisplayport you needed for three monitors.

(NVidia supports only two monitors from any of its single cards but is changing this in Q1 or Q2 of 2012 with its GTX600 series).

Summary:
HD6950 2GB recommended.

 

[photonboy]

Great review on HD6950/6970:

http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/38899-amd-radeon-hd-6970-hd-6950-review.html

 

[Friznutz]

your immaturity and lack of knowledge about computer hardware is showing through.

And you lack of complete facts and stupid recommendations is absurd.
Yes I would agree 2 6900's would be IDEAL but doesn't me I would tell him that. Because he can only afford half of that.

I may be an asshole but I am not immature.

If I am wrong (which I probably am) please elaborate for future reference.
And please dont start off with "Yes. You are wrong"

 

[jyjjy]

You make no sense.
There will be the same amount of VRAM all together. And 1 screen will get a full 1gb or VRAM. If you get a 2gb each one will get about 656ghz each monitor. And who cares about the rebate that much. It will only cost you $4 more than a standard 6770. You really must read my post before saying the stuff you say.

Here it is if you still dont understand.

Monitor 1-main gaming monitor which will display center view- supply by the 1 6790 (for $120) full 1g vram being pushed to that monitor....
Monitor 2+3- Side monitors both using 1 6790 each receiving 512mb vram ($99). Those monitors will most likely not be displaying the UI and you will most likely not focus stuff on them.

2 6790's will have a combined 1600 stream processes. With 2x840mhz combined GPU speed. (monitor 1 will get a full 800 stream processes and 840mhz core speed with 1gb vram and monitor 2+3 will get 400 stream processes each, 420mhz core speed and have 512mb of VRAM each (this is all theoretically separated ratio)

if you have a 6950 you get 1408 stream processes. With only 1* 870mhz core speed (each monitor will get (theoretically) 469 steam processes and have to share 2gb of VRAM (666mb each)


Therefore making you main display, which will most likely display most of the game data, have the most amount of power.
6790 (maybe lag in 2+3 screens)
6950 (if there is lag, will be on all screens)

I'm unsure where you got all this from(did you just make it up?) but basically nothing you've said above is accurate. That is simply not how Crossfire works or how gaming on multiple screens is rendered. In crossfire the multiple GPUs are treated as a unit, each having its own memory which is redundant so that the cards all have the same information available and can properly work together in conjunction. The 3 screens would also be treated as one large scene by the GPU(s). There is no splitting of the cards memory/shader resources as you describe to render each screen separately.

 

[photonboy]

Multiple Displays:
http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/38899-amd-radeon-hd-6970-hd-6950-review-9.html

Same article as I linked above. I just wanted to say that if you don't have a Displayport connection you would likely connect like this:

Display #1: DVI->DVI
Display #2: DVI->DVI
Display #3: HDMI->DVI

*DVI-I is a set of wires containing both the wires for DVI (digital) and VGA (analog). A DVI-I->VGA "adapter" is simply connecting to the VGA connections.

The HDMI output is DVI+Audio. The audio is achieved through decoders on the HD6850/70 board and only work with audio formats for movies (no Windows or game sounds). There may be scenarios where this works but I just avoid the entire scenario.

However, I recommend the HDMI->DVI which just passes the video and get your audio straight from the motherboard's audio solution or an addon audio card such as a Creative or Asus card. With good quality speakers (at least $50 stereo or $100 surround) you would see a big difference in quality. M-Audio AV30 or AV40 are really great stereo speakers. You can get more base with a subwoofer setup (2.1) but that also carries throughout the house more by vibrating the floor. If in a basement I'd definitely go with a quality 2.1 setup and inexpensive, but quality addon sound card.

 

[jyjjy]

1) SLI and Crossfire. STAY AWAY! There are micro-stutter issues. Read the recent Tomshardware article. There are other issues as well.

Do you have actual experience with SLI/Crossfire or did you take something said in an article you read WAY too seriously?

 

[Friznutz]

I'm unsure where you got all this from(did you just make it up?) but basically nothing you've said above is accurate. That is simply not how Crossfire works or how gaming on multiple screens is rendered. In crossfire the multiple GPUs are treated as a unit, each having its own memory which is redundant so that the cards all have the same information available and can properly work together in conjunction. The 3 screens would also be treated as one large scene by the GPU(s). There is no splitting of the cards memory/shader resources as you describe to render each screen separately.

So it still completely evens out all data being sent to all displays though both cards?

So if GPU #1 is at %100 load (for now) and GPU #2 is at %50 load. Card #2 would boost up it speed and send data to card #1?

I used to crossfire some older cards and it was not like that.
If GPU #1 was at %100 GPU #2 did nothing about it.
Well. I am sorry if I misunderstood how modern crossfire works and I will admit a strange defeat. (even though this wasn't a debate)

Still in that case, 2 6790's will have more stream processes combined together than 1 6950. Or what he really wants, a 6870.

or do they not share their memory together for some strange reason? therefore making it only 1gb of VRAM usable if all displays are connected to card #1

 

[jyjjy]

Each card has and needs its own memory and own memory bus on its own PCB. Sharing memory through the Crossfire bridge would be slow and unworkable. Crossfire works by having each card render every other frame so they should consistently have approximately equal workloads. This is not new. I'm not sure what you are talking about with "If GPU #1 was at %100 GPU #2 did nothing about it" but perhaps you were looking at a game in which crossfire was not actually supported.
You cannot just add the number of stream processors on two cards in SLI/Crossfire and compare that to a single card. Crossfire does not scale perfectly and how much it does scale will vary from game to game.

 

[geekapproved]

http://forums.anandtech.com/showthread.php?t=2157093

In every review 6790 Crossfire is better than a 6950 1gb and 2gb. And why would you say cross-firing two 6900's. Why dont you read what he says again and not even recommend things that he did not ask for.


EX. If you ask a car dealer for a Honda Accord and he says "No. What you want is a Ferrari. Can you afford it?"
I would say "Um.... Are you an idiot? I am here looking for a well priced car that will get me places. Not something I didn't ask for!"
Then I would leave

I have noticed a ton of stupid people say that kind of stuff. Like ex.
"I am looking for a $100 video card that can run games."
Answer-"If you can get like a. 6990 get that. It runs all games at max settings."
I have seen stuff like that and it is extremely stupid

You my friend are not understanding the OP's needs. Your link shows 1920x1080, the OP is running THREE MONITORS IN EYEFINITY. That would be 5760x1080. You would need 2GB cards for that.