CPU bottleneck - 6990 & 6950 Trifire

sparx1981 · Post by **sparx1981** » 27 Dec 2011, 11:10

Hi guys and girls,

I'm currently running an i7 870 (Oc'd @ 3.52ghz) (1156 chipset) with 8gb of Ram, 6990 + 6970 in trifire.
I can get most things running at full settings and gaming at 6256 x 1152. I do think that my CPU is causing a bottleneck though. e.g. playing Arkham City I'm only getting 50% GPU utilisation.

Does anyone have any suggestion on ways to ease this problem without upgrading my CPU or alternatively... if I did have to upgrade, what chip would be best?

Sadly money is a barrier so I dont want to go up to a new 3930k chip... although that would be nice.

I've also taken a look at 2500k and 2600k chips... these are newer but I wonder if they are much different in performance compared to my i7 870.

Please note that my i7 870 is on the 1156 chipset so I think that this is generation one i7.

Post by **Delphium** » 27 Dec 2011, 13:20

Hi, what drivers are you using and have you got the latest CAP releases?

When you say 50% is that 50% across both cards, or a single card running at 100% and the 2nd at 0%?
Have you tried monitoring your CPU load also, does this cap out at 100%?

sparx1981 · Post by **sparx1981** » 27 Dec 2011, 18:24

Batman Arkham City has 50% utilisation on each GPU. My CPU usage does spike highly though. All I get at the moment while playing this is between 10 and 20 fps on max settings. Looking at the forums though I know this game has problems with Direct X 11 at the moment though.... I dont know if a new CPU will boost performance in these games or not though? E.g. Crysis 2 only uses 2 GPU's no matter what I do but I think that's down to the game. Also I know the i7 870 is a little old now so not sure if an 2500 or 2600 chip would make much if any difference.

sparx1981 · Post by **sparx1981** » 27 Dec 2011, 19:58

It might be worth noting that my RAM is running in single channel mode. Unfortunately 1156 chipsets only allow single channel when running 1600mhz ram. The below link goes directly to the manual for my motherboard.

http://support.asus.com/download/download_item_mkt.aspx?slanguage=en-us&model=P7P55D-E+PRO

On page 2-11 it states "Due to Intel Spec definition X.M.P DIMMS and DDR3-1600 are supported for one DIMM per channel only"

Would this make a massive impact on performance? If so how can I get around it? when I try to run this memory in dual channel it detects 8gb but in windows it says that only 4gb is usable.

I imagine that my other alternative is to get 1333mhz and run this in Dual channel but would this make much difference considering the drop in speed?

sparx1981 · Post by **sparx1981** » 27 Dec 2011, 20:01

NOTE - conversation is also taking place on other forums to maximise expertise involved. Many thanks to all

http://www.tomshardware.co.uk/forum/forum2.php?config=tomshardwareuk.inc&cat=15&post=337771&page=1&p=1&sondage=0&owntopic=1&trash=&trash_post=&print=0&numreponse=0"e_only=0&new=0&nojs=0#t2519031

http://forums.overclockers.co.uk/showthread.php?t=18356231&highlight=cpu+bottleneck

sparx1981 · Post by **sparx1981** » 27 Dec 2011, 23:29

Just to keep this forum up to date it is currently believed on Toms Hardware that the single channel issue could be whats causing the lower than expected performance? What do people on here think?

Will 1333mhz ram be worth investing in? Is it better for me to change motherboard / CPU?

sparx1981 · Post by **sparx1981** » 28 Dec 2011, 10:25

morning guys,

Ok, I've tried getting the ram to work in dual channel again and managed to get it working if I up the voltage to 1.65v. I did have to press the mem ok button to start with but hopefully this was a one off due to the change of config.

So... in short I now have 8GB of Ram in Dual Channel mode.

Sadly this made no difference to my gaming speeds and therefore my orginal question.

I've re-run a test on Arkham City and all three GPU's are using 50%. My CPU doesn't seem to be at 100% either though. Is this a CPU bottleneck or something else (AKA bad programming) causing the game not to use all available resource.

I'm currently running 11.12 and Cap 2 I think.

sparx1981 · Post by **sparx1981** » 28 Dec 2011, 14:23

Just re-done my test with Arkham City both with and without crossfire enabled. I get the same FPS in both tests. So the addition of the 6970 does pretty much nothing. Any ideas?

sparx1981 · Post by **sparx1981** » 28 Dec 2011, 19:04

To clarify this a bit more, Battlefield 3, ultra settings at 6256 x 1152... 40 fps. I'm happy with that. But Arkham City, Metro 2033 and Crysis 2 at max settings get around 15 fps.

Post by **Haldi** » 29 Dec 2011, 18:26

That shows once more that TriFire isnt that much supportet -.-

So you've asked in ArkhamCity if other people have the same problem?

Maybe its because AMD cards have some Problems with Physx?

PwrUsr · Post by **PwrUsr** » 29 Dec 2011, 20:34

99% pretty sure only Nvidia cards run PhysX, not AMD; CPU handles the physics using software PhysX when AMD video cards are used.

To be honest with you it really doesn't sound like a CPU bottleneck, especially if you're getting better framerates at the same settings with the same hardware in other games, as you mentionned. If it was indeed a hardware bottleneck at the CPU level you would probably be seeing similar performance in all games, which you are not.

This sounds more to me like software issue, either driver related or that the games in particular where you're seeing lower performance just aren't coded as well or as efficiently.

Those newer chips you mentionned are faster than what you have but only marginally so, and past that point generally don't make such an impact on gaming performance compared to raw GPU muscle, which you already have. Speaking of which, I seriously suspect an issue with tri-fire implementation, even more specifically seeing as the GPUs aren't seeing high utilization this may be more related to a motherboard PCIe bandwidth limitation. What board is that, and how are the PCIe lanes arranged?

sparx1981 · Post by **sparx1981** » 30 Dec 2011, 18:57

You're completely right about AMD not running Physx. I think the CPU does this if an Nvidia card isn't present.

As for the motherboard its a 1156 chipset and the model is an Asus P7P55De-Pro.

2 x PCIe 2.0 x16 (single at x16 or dual at x8 / x8 mode)
2 x PCIe 2.0 x 1(5GT/s, blue slots)
1 x PCIe 2.0 x 1(2.5GT/s,gray slot)
2 x PCI

I dont know if there is a better motherboard that is actually worth investing in. Seeing as this one work I mean.

valyard · Post by **valyard** » 17 Jan 2012, 10:44

I got similar problem but with 2 6970 cards and 3xFullHD displays. Crysis 2 is fine with eyefinity and crossfire. But Skyrim runs at 10fps at crossfire. Both GPUs are used on 50-70%, CPU is not maxed either. Turn off crossfire — getting 25-30fps. Where's the bottleneck? o.O

I guess 5760x1080 is too big and crossfire bridge/PCIe might be the bottleneck. I checked both cards run on PCIe 2.0 8x.

Post by **Haldi** » 17 Jan 2012, 21:40

AFAIK Crossfire Bridge only transfer the timings, all data is transferd over PCI-E !

I'd say its a problem with failing Crossfire drivers for Skyrim! Try out Skyboos Acceleration Layer. Might help with CPU limit!

Widescreen Gaming Forum

CPU bottleneck - 6990 & 6950 Trifire

CPU bottleneck - 6990 & 6950 Trifire

Hi, what drivers are you

Batman Arkham City has 50%

It might be worth noting that

NOTE - conversation is also

Just to keep this forum up to

morning guys,Ok, I've tried

Just re-done my test with

To clarify this a bit more,

That shows once more that

99% pretty sure only Nvidia

You're completely right about

I got similar problem but

AFAIK Crossfire Bridge only

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