Bottleneck with FX-8320 and 270X (crossfire)?

Andrew Buck

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I have a system with one R9 270X already and have $200 and am thinking about getting another. I have an AMD FX-8320 overclocked to 4.2 GHz (Cooled with H60) and an ASUS M5A99X EVO R2.0. I have one MSI Gaming R9 270X and am wondering if the dual X8 versus single X16 slots will bottleneck me in BF4, as well as the CPU at 4.2GHz. Also, what is the difference between X8 and X16 and will the Crossfire Bridge reach the other card when it is in the other slot? Thank you very much!
 
Solution
Dual 270X cards will not be bottlenecked by your processor. And the x8 slot @ 2.0 has more bandwidth than the cards can saturate. You're good.

The CF bridge that comes with the cards should fit the standard spacing of your board's PCIe X16 slots.

clutchc

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Dual 270X cards will not be bottlenecked by your processor. And the x8 slot @ 2.0 has more bandwidth than the cards can saturate. You're good.

The CF bridge that comes with the cards should fit the standard spacing of your board's PCIe X16 slots.
 
Solution

Andrew Buck

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Alright, thanks! Where can I find a Crossfire adapter for that size?
 

clutchc

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If you buy a new card, it will come with one. Didn't your first card come with one?
http://www.amazon.com/s/ref=sr_nr_n_0?rh=n%3A172282%2Cn%3A284822%2Ck%3ACrossfire+Bridge&keywords=Crossfire+Bridge&ie=UTF8&qid=1400946484&rnid=493964
 

Andrew Buck

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My first did not, might my second one?
 

clutchc

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Maybe they quit doing that. Used to be AMD always gave the bridge with the card, and Nvidia gave theirs with the SLI motherboard. I just bought a R9-280 for another machine. Checking the box, I see there's one in it. So I would think an R9-270X would have one too.
 

Andrew Buck

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Ah - I have looked stuff up - for some reason, MSI does not give the Crossfire Bridges. I see that the Fry's right around the corner does not have a bridge, but the one forty-five minutes away has it. I am not sure if it is worth it. Also, what brand would you recommend? I could get another brand that has a bridge included.
 

clutchc

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If you can match the card you have, that will be best. If not, I really have never had a bad gfx card yet, so all I can say is find one as close to the one you have now. Same size speed memory. I have an Asus Direct CU II OC 290X in this machine, and a Sapphire Dual-X 280 in another machine.

The bridge isn't necessary to run CF, but the performance will suffer at peak demand w/o one. W/o the bridge, all the data between cards has to flow via the PCIe interface.
 

Andrew Buck

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I am indeed getting bottlenecked. My GPU1 and GPU2 usages on BF4 maps (not China Rising maps) are around 30-35% usage at all times. Any suggestions? My socket temp gets to 65 C while playing BF4 @ 4.2 GHz @ 1.344 V. I do not know why it is getting this high.
 

Andrew Buck

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f4fuco.jpg


Something I noticed - cores being parked. I have tried multiple core unparking programs, such as ParkControl and CoreParkingManager, but the cores are still being parked.

ALSO - GPU2 usage at 50% - for some reason when I went windowed it did that.
 

clutchc

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Unless AMD made changes to Crossfire recently, CF shuts off in window mode. It used to only work in full screen.

I can't believe that the FX-8320 is bottle necking the pair of 270x cards. Let's see what your CPU usage is next to the GPU(s) usage.

Another thing, BF4 is still problematic in multiplayer. If I had a dollar for every poster with a problem getting smooth gameplay online with that game... I'd be a rich man.
 

Andrew Buck

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I tested with Mantle. In the beginning, I do admit, I got higher framerates and the GPU/CPU graphs in BF4 were smooth with GPU being higher. Quickly, it started to get jagged and then I had huge CPU values jump to 500, later 3000, correlated to massive frame drops. I used 2570 MB/2048 MB VRAM (I assume that it is probably out of 4096 MB because of Crossfire) and got drops as it increased. DX11 is steady and jagged with CPU/GPU close, GPU being higher. I still don't understand why on Shanghai, Flood Zone, Hainan Resort, and just about every other BF4 map besides Operation Locker and China Rising maps have sub-60 fps.
 

clutchc

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Here is a discussion on Core Parking with 8 core amd and intel cpus in BF4: http://pcrepairaugustaga.com/bf4-parked-multi-core-cpu-fix/
I don't have an 8 core and I don't play tag with guns, so I have no personal experience with the game.
 

Andrew Buck

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Thanks for fixing my core parking issue, but one remains:
16jrfy1.jpg


My CPU is high and I am still getting fps in the 35-50 range.