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Bottlenecking my xfire 6850s?

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a b K Overclocking
June 2, 2012 1:30:37 AM

Is a Phenom II x6 1065t Stock at 2.9 ghz; now over clocked to 4.1ghz bottle necking my games?

I find that in CPU dependent games I am consistently limited to 39-45 FPS regardless of settings and according to benchmarks on crossfired 6850s I should be able to do way better than that.

So is it this cpu which is bottle necking them?


Second question; is there an am3 or am3+ CPU which will not bottle neck these cards? I don't want to drop 300$ on a 2500k setup right now.
June 2, 2012 3:45:54 AM


What apps or you speaking of?

First thing, just speaking on terms of a single GPU, that Phenom II, especially at that clock, should not bottleneck your 6850. I assume you have a 890 or 990 chipset, and they are pretty damn fast and play well with CPU - GPU combinations. My 1045t with a 6850 on an 890 chipset ran very well together, although it seemed there was a slight bottleneck at stock clocks. Right now, I have a FX-6100 @ 3.9 (on stock air) with a HD 6850, and they work VERY well together. I definitely run CIV 5 better, and by that I mean awesome, and that is super CPU intensive, so you should have no problems with your current set-up. Don't know how much of a difference the chipset would make for you in that regards, but the 990 was made for the 6XXX and 7XXX GPUs.

Second, I ask what apps, because some make much better use of you six cores than others. Even the good ones rarely access more than four, but most CPU intensive software is pretty good about CPU utilization.

Just a note though, something I don't see mentioned a lot in these forums, one of the best performance upgrades you can have is a second Hard Disk. That would greatly help you in the realm of CPU intensive apps, which are generally ram intensive. Allows your computer to read and write to page file at the same time without waiting really helps overall performance on the system level, and makes windows a lot happier, you just have to make sure you have pagefiles on both disk.

Lastly, you have two 6850s man, I know there are much more powerful enthusiast cards, but the 256 bit processors are no joke man ( they are 1.5 TFLOP chips, the first 1.5 TFLOP machine on the planet was in 1996 at the Sandia National Laboratory, and it was HUGE, so that thing in the back of your machine is as powerful as the most powerful massively parrelled computer in 96), so your not going to find a cheap processor that can keep up with 2 of them. I was thinking about getting a second 6850 for my 6100, but I know that on CPU intensive things, I can expect performance close to what I have now. Wouldn't really call that bottleneck though, it's just the limit of your processor.
a b K Overclocking
June 2, 2012 4:04:11 AM

Here is my compete setup:

CPU: AMD Phenom II x6 1065t @ 4.1 ghz/1.51250v
CPU Cooler: Cooler Master V6 GT
Mobo: Asus M5A99x EVO Ram: 8 Gigs RAM
PSU: Cooler Master Silent ProM 850
GPU:2xCrossfireX Asus 6850
Case: HAF 912

My motherboard is a 990

As for the applications almost any game which is PC exclusive is stuck rendering in that 40-35 FPS range regardless of settings (bare minimum or full max) some games have a plateau which is usually due to AA and shadows and Post processing but I can basically play any game maxed but at 40 fps max.

Console ports often run at 60 fps on max.
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June 2, 2012 12:36:22 PM

It sounds to me that 40fps is about as fast as your cpu can feed your graphics card. Just as an experiment: drop your overclock a bit and post your frame rate. Also, your graphics cards are running at stock?
a b K Overclocking
June 2, 2012 3:57:32 PM

The 40 fps barrier happens at 2.9ghz and 4.1 ghz

My cards are OC'd to 900/1170 right now but even at stock 790/1000 the fps is around 33-35 i get about 5 fps OCing them in most applications but I think I'd get more with out the bottle neck.

My main question is; with out going to a 2500k setup is it possible to get an am3 or am3+ CPU which should /could alleviate my issue or should i just save a little longer and buy the intel set up.
June 2, 2012 6:10:36 PM

If the barrier exists regardless of cpu speed, I would look elsewhere for a bottleneck. Maybe your gpu overclocks are unstable?
a b K Overclocking
June 2, 2012 8:51:35 PM

Happens regardless of stock or OC, some games are locked to about 40 and others run free. One that really confuses me, is most ARMA 2 (Dayz) servers Im locked to 40 fps but some i can do 60 and others nerf me completely down to 20. I watch gpu usage and some servers utilize 100% gpu and others dont use more than 2%
June 3, 2012 2:39:39 PM

yeah, an x6 at 4.1 GHz i doubt would bottleneck even 6850's. astjs4ever said, id look at other bottlenecks.you said it happened on just SOME ARMA2 servers. ive never played arma2, so IDK, but maybe youre having network errors that could cause it? ARMA2 is also very intensive, so it might possibly be a VRAM limitation. HMMM. it might be a stretch with an 850 Watt, but that MAY be be a PSU problem. thats a big maybe, though. i doubt that the CPU is either getting too hot, nor do i think its unstable at that voltage, but hey, who knows.
June 3, 2012 5:39:05 PM

Try over locking CPU only. Some gpu's show OC instability in the weirdest ways (especially when OCing the gpu RAM: they don't always like that). Can you run GPU-Z and verify your graphics adapter is running in full PC express x16 v2 mode?

It may be possible that your CPU OC is not 100% stable: run a blend test in prime95 and run a few Intel burn tests.
a b K Overclocking
June 4, 2012 2:06:47 AM

For Arma, it depends on the server.

Since the most recent dayz patch i am 60 fps all the time now.

Some other games are still limited though.

I've tried just the gpu just the cpu and no difference. It also happens with only one GPU installed in x16 v2 unfortunately in crossfire it drops to x8 and x8. That said all the reading i've done indicates it makes almost no difference.
June 4, 2012 2:14:50 AM

Can you post a futuremark score? And can you post heaven benchmark results? It sounds to me more a limitation of the specific games you are using, than a limitation if your machine. The lack of changes from CPU overclock suggest there isn't a significant bottleneck. Let me know if I can help further
a b à CPUs
a b K Overclocking
June 4, 2012 2:47:52 AM

bobusboy said:
The 40 fps barrier happens at 2.9ghz and 4.1 ghz

My cards are OC'd to 900/1170 right now but even at stock 790/1000 the fps is around 33-35 i get about 5 fps OCing them in most applications but I think I'd get more with out the bottle neck.

My main question is; with out going to a 2500k setup is it possible to get an am3 or am3+ CPU which should /could alleviate my issue or should i just save a little longer and buy the intel set up.



So... you already solved this 6 posts back then? When you overclock the CPU nothing changes. so the CPU is (and should be) plenty. When you overclock the GPU FPS go up. when you drop the overclock they go down. They are clearly not bottlenecked by the CPU.

You're running everything maxed. you're getting 40-60+ FPS like you should. I don't see the issue
a b K Overclocking
June 4, 2012 3:11:32 AM

unksol said:
So... you already solved this 6 posts back then?


No it's not fixed.


Some games are arbitrarily limited to 40 fps regardless of settings. Others are milted to 40 FPS depending on what server I'm connected to.

The CPU clock makes no difference.

And you mean to tell me that to spite all the benchmarks out there that two 6850s in cross fire with a 6 core CPU running at 4.1ghz shouldn't be able to hit 60+ fps in every game at 1080p.


I was hoping that some one else with xfire 6850s with a different CPU would chime in and let me know what performance in what applications they have. So that I could compare.
a c 283 à CPUs
a c 110 K Overclocking
June 4, 2012 3:16:28 AM

It sounds like certain games you're trying don't like CF (does happen). Have you tried disabling CF to see what happens?
June 4, 2012 3:17:07 AM

Best comparison would be run some popular benchmarks and POST your results. We can't go over to your house and do this for you. You have a decent setup, we need to establish that there is in fact an actual bottleneck before we can give a cause and solution. I need some data to work with.
a c 283 à CPUs
a c 110 K Overclocking
June 4, 2012 3:18:46 AM

I honestly think it's related to CF and a possible driver issue. There's no other explanation...
June 4, 2012 3:21:14 AM

I agree with DJ but without more information, we're just guessing.
a b K Overclocking
June 4, 2012 6:04:13 PM

I posted some specs in another thread a few weeks ago, I'll go dig it up.
a b K Overclocking
June 4, 2012 6:07:58 PM

Edit: Will post results of:

Furmark
Heaven 2.1
3d mark 7 lite
3dmark 11 lite
3d mark vantage lite.

If you want to see other benchmarks let me know what they are.
June 6, 2012 1:10:12 PM

In my opinion you have some other issues..My system is very similar and i don't have the problem you do..
Phenom II x6 1045T @ 3.8 ghz , 12 GB ddr3 1600,dual sapphire hd 6850 in crossfire...
at 3.9 ghz on cpu i get 7628 points in 3dmark 11
http://3dmark.com/3dm11/3714750
playing bf3 i get a low of 50 fps and a high of 120 fps on 64 person MP servers..all ultra settings 1920 x 1080 post AA max af no hbao..
I'd suggest running 3dmark 11 to compare..
!