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6850 CF

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a b U Graphics card
October 31, 2011 5:02:10 PM

So I've been mulling over this a'lot lately. And I've heard a'lot of biased opinions on the matter.... But is the 6850's micro-stutter really that bad? And would my monitors refresh rate be a problem, here's the link: http://www.newegg.com/Product/Product.aspx?Item=N82E168...

Also my system specs,
Amd 1100t
3gigs ddr2 1066 mhz (Oced)
500watt ocz psu (Yes it is a good enough psu)

Thanks for reading,
Eli
:bounce: 

More about : 6850

a c 143 U Graphics card
October 31, 2011 5:33:30 PM

More simplified article and review than Tom's
http://hardforum.com/showthread.php?t=1317582

In short, it's a phenomenon happens with most of multi GPU setups but you'll experience it more with low end & mid range GPUs configurations.
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a c 169 U Graphics card
October 31, 2011 5:34:16 PM

First of all,you can't use 2 6850s on that PSU.(you have to upgrade it)
As for micro-stutter,well multiGPU setups have this issue in some games.Sometimes it is solved by a driver update or a fix from the game makers and sometimes it isn't.
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a c 125 U Graphics card
October 31, 2011 5:58:12 PM

It seems like the 68xx cards are getting a bad rep for micro stutter. I haven't used them myself, but with my 5850s I've not noticed the phenomenon at all. I mean, I've noticed framerate drops but that can happen no matter what if some intense *** is going on.

I'd say it's worth trying, just make sure whoever you buy from offers a 1 week return policy :) 
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a c 143 U Graphics card
October 31, 2011 6:01:18 PM

The problem is most of users don't feel the Microstutter or even know what Actually it is, this is the only case i recommend 2 HD 6850s if FPS and smoother games what matters.
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a c 106 U Graphics card
October 31, 2011 6:32:33 PM

When micro stutter does appear yes it is a little annoying, but with vsynch enabled you don't really have to worry about microstutter. Microstutter annoyed me more when I was using two 3850s in CF but then I often didn't enable vsych because I needed every fps I could get ^_^.

Your PSU is enough, but considering the OCZ units are only of decent quality I would think about getting a better one in the future

http://www.guru3d.com/article/radeon-hd-6850-6870-cross...

Also make sure you have decent case ventilation as adding that second card for CF really does increase the temps of everything else.
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a b U Graphics card
October 31, 2011 6:44:02 PM

in my mind, microstuttering is like compression on mp3 files, most people don't notice the affect of it.

If you can find a place that offers returns, you can always try it out, and if it is really noticeable then return it. If you don't notice, then blissfully play your games while being ignorant of the fact that some frames are getting chopped short.

~~~~

As for the PSU, AMD suggests a 500W or higher. You have a 500W PSU, but I don't think it is going to cut it. You have a 125W CPU, and two 125W GPUs, which is 375W on the 12V line assuming you aren't overclocking (and not including other devices). You'll need roughly 36A peak, and if I got the right PSU yours can put out 36A, but on two rails. Since each rail is 18A, you may overdraw one of the rails, of if you are "lucky" the real over current protection isn't until you hit 20A or a little higher. However, a quick search says that isn't likely to happen especially when the unit is hot.

Hardware secrets says the rails are set up like so:
+12V1: The cables that are permanently attached to the power supply.
+12V2: The cables from the modular cabling system.

They also say that the over current protection kicks in at 20A at cold, and at 18A when hot.

Sounds to me like you need a new PSU, but you might be able to get it to work. Personally I'd try it, but I'm guessing your system is going to shut off to protect itself and you'll have to upgrade either to a single rail PSU, or a 550-600W dual rail PSU. (either way, I'd step up to at least a 550W PSU)
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a b U Graphics card
October 31, 2011 7:38:29 PM

Thank you guys for your replys. I do have a second psu just kicken around and i'll use that. The airflow is not a problem - because i have a test bench. But my monitors refresh rate does make me a little disconcerted. The link is at the top! I don't know if a vertical refresh of 55-70 is good.
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October 31, 2011 11:02:11 PM

I believe that Vsync locks your frame rate to the refresh rate of the monitor. My monitor refreshes at 60 Hz (or 60 times/sec), so Vsync would lock my framerate at 60fps (frames per second).

Someone please correct me if I am wrong.
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a c 125 U Graphics card
November 1, 2011 4:19:57 AM

That's a very odd way to display the monitor refresh rate...

Anyway that doesn't have anything to do with microstutter. I would think, if anything, a low response rate like 2ms might show microstutter more than 5ms. My monitor is 5ms so maybe that's why I don't see it where other people do.

Fact is, at least as far as I'm aware, nobody really knows how come some people will notice it a lot and others don't, unless it's actually just an anomaly between certain cards. Might be all cards do it the same and some people are more sensitive to it, or maybe the monitor makes it more apparent. I don't know.

Like I said, might as well try it. The higher the FPS, the faster the frames go by and the less likely it is to see the stutter. CF 6850s can easily hit your max refresh rate in most games so I wouldn't really worry about it.

And yes, VSync will cap your framerate to your monitor's refresh rate (probably will be 60 or 70 with that monitor). Due to the cap it can cause worse performance, as it will often dip below 60 and never exceed it. This will happen even if with VSync disabled you can hit 80fps. It's just a... flaw... with VSync and a main reason a lot of gamers don't use it unless they really need to.
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a b U Graphics card
November 1, 2011 4:29:42 AM

Just my 2c,

i was running 2 6850s for the last 6 months. The ONLY time i encountered a problem was with BF3. (minor problems with crysis 2 also, but that's kinda gimped with crossfire anyway)

There were 2 or 3 games with very minor stuttering, but enabling triple buffering in the display drivers always fixed it for me.
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a c 171 U Graphics card
November 1, 2011 4:46:02 AM

as has been said, its only really noticeable at lower fps, things like vsync, tripplebuffering and apparently locking the fan speed can help reduce it.
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a c 106 U Graphics card
November 1, 2011 2:57:34 PM

hispeed120 said:
I believe that Vsync locks your frame rate to the refresh rate of the monitor. My monitor refreshes at 60 Hz (or 60 times/sec), so Vsync would lock my framerate at 60fps (frames per second).

Someone please correct me if I am wrong.


You are correct. Basically a frame is not pushed to your monitor until your monitor is ready to accept it to prevent things like screen tearing, which happens when a frame is still being drawn when it is pushed to your monitor partly with the new frame and partly with the old frame. When it's consistent the top portion of the screen will look slightly different than the bottom one and the line of this difference may move during the course of game play.

As long as your GPUs can push at least a consistent 60fps (or 120fps if you have 120hz monitor) you won't be missing any frames.
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a c 106 U Graphics card
November 1, 2011 3:03:25 PM

I should add of course that if your GPU(s) push out less than 60fps then your monitor will display the previous frame if the next frame isn't ready rather than drawing a partial frame to the screen. That will slightly delay near future frames, so if your card has trouble maintaining that 60fps you may get smoother play by disabling v-synch. One thing I like about my big ol 19" CRT was that it had an 85hz refresh rate, but I'm pretty share it shaved off a bit of my vision with all that gaming :D .
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a b U Graphics card
November 1, 2011 4:48:07 PM

You guys have helped a'lot in my decision. And i have already started looking for a good deal for a 6850; MOBO; RAM. (DDr3 ram of course). Can you guys help with this? My budget is around 250...... It'll be around December when i buy this....
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a c 125 U Graphics card
November 1, 2011 5:52:37 PM

What do you need a mobo for?

IMO just get a 2x4gb RAM kit like GSkill Ripjaws for $50, get a 64 bit OS (Windows 7), and a GPU.
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a b U Graphics card
November 1, 2011 5:59:52 PM

I already have windows 7....... And a 6850; so that isn't the problem :p ........ I also have a Amd 1100t.
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a c 125 U Graphics card
November 1, 2011 9:41:18 PM

Oh ok, I guess your 3gb of RAM through me off, figured you have a 32 bit OS.

So yeah, seems to me like new RAM and a GPU and you should be a-ok. Maybe a PSU, and if you can give that CPU a little OC I'm sure it'll help as well. Might need a cooler for that, like a Hyper 212 Plus (it's the cheapest good one at only $30)
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a c 171 U Graphics card
November 2, 2011 1:29:24 AM

Quote:
As for the microstutter complaints.
I got it on a single 4870.
I have no clue why as i was using a 955 BE with a 790FX-GD70, but it was very noticeable.
Microstutter is a game breaker in the sevear cases and is totally devistating.

no, you didnt get microstutter on your 4870, you just got stuttering. there is a difference.
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a b U Graphics card
November 2, 2011 2:43:28 PM

iam2thecrowe said:
no, you didnt get microstutter on your 4870, you just got stuttering. there is a difference.

What would the causes of regular stuttering be?
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a c 106 U Graphics card
November 2, 2011 3:25:04 PM

You'd get stuttering if your system simply wasn't fast enough for your given settings causing sever drops in FPS. It's annoying. Micro stuttering happens when the frames are not being rendred in regular intervals. For example if you had 45 fps and every 2nd or 3rd frame took longer to render than the other frames that would be micro stutter. Of course if you have a min of 60fps and v-synch enabled that doesn't matter because frames are pushed to the screen in regular intervals and only when they are completed (to prevent tearing).
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a b U Graphics card
November 2, 2011 3:58:48 PM

Could the hard drive be a cause of stutter?
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a b U Graphics card
November 2, 2011 4:05:15 PM

Sorry, i'm a noob! But what is a BSOD?
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a b U Graphics card
November 2, 2011 4:17:40 PM

Mine does that occasionally D:
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a b U Graphics card
November 2, 2011 4:18:09 PM

I think i'm just going to get an SSD and wait for crossfire!
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!