Two 1GB cards in crossfire or one 2GB card?

bigolbig

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Hello all,

I recently had my Sapphire Radeon 6850 1GB 256 bit card fail so while waiting for the replacement to come in I bought another of the same model. Today I received the replacement so now I have two of these 1GB cards. My MB (Gigabyte GA-970A-UD3) has only one x16 PCI-E slot (the other is x4), so I don't think using crossfire with this MB is going to improve my system. The question is: which would produce better performance - the two 1GB cards running in two PCI-E x16 slots using crossfire or one Radeon 7850 2GB 256 bit card? (I'm thinking about getting this one http://www.newegg.com/Product/Product.aspx?Item=N82E16814131472&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&AID=10446076&PID=3938566&SID=) Either scenario would require me to purchase new parts, either a new MB or new card, so we don't have to take money into account here.

Thanks
 
Solution
You would want with 2 gigabytes over 2x 1 gigabyte cards. Because with a Sli setup you would still only have 1 gigabyte of video ram where as with the 2 gigabyte card you would have 2. If you could get either the 660 listed above or one similar or the 7850 you suggest with 2 gigabytes of ram it would be better for you. You run into far less issues by sticking to one card as well.

samuelspark

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You can run at x16 and x4. It won't be good as x16, x16 or x8, x8, but there will still be a significant improvement.

Normally, I would recommend one card, but since you have already bought them, there's no reason to get another.
 

bigolbig

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So even though one card is running at x4, I will still see improvement? I was under the impression that this would not improve performance and could in fact degrade it.
 
You would want with 2 gigabytes over 2x 1 gigabyte cards. Because with a Sli setup you would still only have 1 gigabyte of video ram where as with the 2 gigabyte card you would have 2. If you could get either the 660 listed above or one similar or the 7850 you suggest with 2 gigabytes of ram it would be better for you. You run into far less issues by sticking to one card as well.
 
Solution

MC_K7

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Increasing the amount of memory on a card won't necessarily give you better performance. Most people don't need more than 1 GB so the extra memory would just be a waste in most scenarios. Unless you're playing on 2 monitors at the same time or have 1 monitor with a very high resolution (2560 x 1600 or higher).

Also, Crossfire doesn't work like that, if you put two 1 GB cards it won't give you a total of 2 GB, your games will still see that only 1 GB of memory is accessible.

Assuming you're using only 1 monitor with a standard 1080p resolution, in that case Crossfire will give you a very significant boost vs. probably no difference at all compared to one card with 2 GB of memory.

Finally, even though you already have purchased the card, it might not be too late to send it back to the store and get reimbursed.
 

devilofdeaths

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bf3 at 1080p uses 1.5gb of VRam http://hardforum.com/showthread.php?t=1664929
 
The paired 6850's would generally outperform the 7850 at stock speeds *if* you game at less than 1920x1080 or @1920x1080 on medium settings. however, with textures (and some other graphic settings) turned up, or at resolutions at or beyond 1920x1080, the 2gb on the 7850 will put it in the lead. Also, the 7850 is a beastly overclocker so if you tweak you cards, the 7850 is a clear winner.
 



being as nice as possible I totally disagree with most of what you stated. I found in the past that 1gig of vram at 1600 resolution or above isn't enough. Add DX10/11 into the mix and/or higher resolutions than that and adding more of what's available in most newer games control panels, .........making that statement is mind boggling. Totally inaccurate.

 
I don't understand why people think that by people saying 2 GB is better that it means that we are saying it will improve performance. There are plenty of games that go over 1 gigabyte of memory. BF3 being the most common of those examples. A 7850 will offer better DX11 support will supply more memory granted you get the 2 gigabyte model and if you experience stuttering with crossfire well a good chance is you wont with a single card. Same goes with the gtx660 which outperforms the 7850 at stock.
 


There's more to gaming performance ( video card performance ) than just how many frames you get. Somehow that always seems to get lost. Whether it's from people who post on forums or by the staff that does benchmarks and posts the just numbers. Very often misleading.
 
Right, people normally leave out the quality of life things out of reviews certainly. Like I tell people normally all you get is what people consider to be the best. You see it all over the forums. Very misleading. If a game uses more then a gig of ram surely you will notice more stable play while playing a game doesn't mean it will be more frames as a result but more stable.
 

samuelspark

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i would take the 7850 2gb over 2 x 6850's any day. I had 2 6850's, bought a second one cheap off ebay for crossfire, found myself selling them both within a month due to crap performance and microstuttering. As has been mentioned many games use more than 2gb vram these days, BF3, Crysis 2, Skyrim, and when that happens you get jerky gameplay, as the system has to load from system memory instead of your graphics cards faster vram, causing slowdowns and stuttering. My single gtx660 offers a much smoother playing experience.
 
Right if you wanted to handle say Skyrim with a ton of mods or GTA IV with a ton of mods you would want a higher end card with more ram like a 670 with 4 gigabytes or a 7970 stock with 3 possibly with 2 cards in tandem. There is just more stability like you said crowe from using 1 card. You have a more stable experience, you have a cooler computer, and you use less power more often then not.