XFX 6950 2GB SERIOUS ISSUE *Everyone Read*

Well well... When I have Crossfire off and run 1 card I get 6.9GB max. With Crossfire ON I get the good ole 800's. Board is 16x/16x.

 

with 11.2's


Devices found: 1

===> Testing device 0 <===
Device type: Unknown
Max resource 2D width/height: 16384/16384
Total GPU memory size: 1024 MB
Total CPU cached space size: 1471 MB
Total CPU uncached space size: 1471 MB
GPU engine clock: 775 MHz
GPU memory clock: 1125 MHz
Number of timing loops: 100
[ 16 bytes] CPU->GPU= 68.357 KB/sec, GPU->CPU 125.750 KB/sec
[ 32 bytes] CPU->GPU= 567.605 KB/sec, GPU->CPU 324.935 KB/sec
[ 64 bytes] CPU->GPU= 1.317 MB/sec, GPU->CPU 1.466 MB/sec
[ 128 bytes] CPU->GPU= 3.018 MB/sec, GPU->CPU 2.979 MB/sec
[ 256 bytes] CPU->GPU= 6.124 MB/sec, GPU->CPU 5.998 MB/sec
[ 512 bytes] CPU->GPU= 11.966 MB/sec, GPU->CPU 10.581 MB/sec
[ 1024 bytes] CPU->GPU= 21.001 MB/sec, GPU->CPU 20.887 MB/sec
[ 2048 bytes] CPU->GPU= 41.584 MB/sec, GPU->CPU 41.972 MB/sec
[ 4096 bytes] CPU->GPU= 79.559 MB/sec, GPU->CPU 80.933 MB/sec
[ 8192 bytes] CPU->GPU= 163.108 MB/sec, GPU->CPU 155.277 MB/sec
[ 16384 bytes] CPU->GPU= 295.296 MB/sec, GPU->CPU 325.949 MB/sec
[ 32768 bytes] CPU->GPU= 878.200 MB/sec, GPU->CPU 831.699 MB/sec
[ 65536 bytes] CPU->GPU= 1.559 GB/sec, GPU->CPU 1.533 GB/sec
[ 131072 bytes] CPU->GPU= 3.150 GB/sec, GPU->CPU 2.892 GB/sec
[ 262144 bytes] CPU->GPU= 4.639 GB/sec, GPU->CPU 5.003 GB/sec
[ 524288 bytes] CPU->GPU= 4.944 GB/sec, GPU->CPU 6.599 GB/sec
[ 1048576 bytes] CPU->GPU= 5.288 GB/sec, GPU->CPU 6.826 GB/sec
[ 2097152 bytes] CPU->GPU= 5.553 GB/sec, GPU->CPU 6.967 GB/sec
[ 4194304 bytes] CPU->GPU= 5.474 GB/sec, GPU->CPU 7.026 GB/sec
[ 8388608 bytes] CPU->GPU= 5.506 GB/sec, GPU->CPU 7.070 GB/sec
[ 16777216 bytes] CPU->GPU= 5.526 GB/sec, GPU->CPU 7.087 GB/sec
[ 33554432 bytes] CPU->GPU= 5.521 GB/sec, GPU->CPU 7.096 GB/sec
[ 67108864 bytes] CPU->GPU= 5.532 GB/sec, GPU->CPU 7.098 GB/sec
[ 134217728 bytes] CPU->GPU= 5.546 GB/sec, GPU->CPU 7.101 GB/sec
[ 268435456 bytes] CPU->GPU= 5.537 GB/sec, GPU->CPU 7.102 GB/sec
[ 536870912 bytes] CPU->GPU= 5.514 GB/sec, GPU->CPU 7.102 GB/sec
[1073741824 bytes]

 

Do i win?

 

lol,yeah you win if you really want it

I actually found this topic kinda interesting, not because the issues but because I never gave it much thought.......

I'm certain this tool is not reliable, but didn't make much difference between 10.10's and 11.2's for me...

 

Ah, I totally think it is.. I ran it the first time and it came back at 4.7Gs... I was like wtf cause it should be well over 5 for this board cpu and gpu.. So i messed around with afew things, (knowing my nb is at 2700 and my HT is 2400) So i saw my PCIe was on auto in bios.. thought hmm... Switched it to 125, bam, well over 5.2Gs, Bumped it up to 135, then 145, and 150.. 150 is as high as it goes.. But omfg! Every game screams now and you can feel the difference.. I have always read leave it alone. dont mess with it, you wont see a difference... lmao! Those of you who have a lower number.. try bumping it to 110.. see if you can handle that..

 

Wait a sec.. Look at my GPU->CPU 4.8.. Im seeing everyone else around 5~6

what could be causing that. hmmmm.

 

don't run your pcie over 110 ish you'll fry your card.


"Look at my GPU->CPU 4.8.. Im seeing everyone else around 5~6"

from what I read earlier in this thread the gpu>cpu is not important

 

Whether it even makes a difference or not, I've pin pointed the strange results on mine down to crossfire being ON or OFF. When using just 1 card (10.10e, 11.1a, 11.2) All spit out numbers of 6.9GB. When using both cards it drops back to 800MB. Wonder if this effects Multi GPU configurations or it is just a display error of some kind.

 

from:http://webcache.googleusercontent.c...&gl=us&client=firefox-a&source=www.google.com




PCI Express Bandwidth Issues

The bandwidth issue is a product of chipsets with too little peripheral connectivity and motherboard vendors pressured to include copious value-added functionality. As long as USB 3.0 and SATA 6Gb/s aren’t built into Intel's and AMD's core logic, those controllers remain add-on devices that require an interface with ample throughput. The interface of choice, naturally, is typically PCI Express, which currently spans two generations of technology. PCI Express 2.0 offers 500 MB/s throughput per lane, while PCI Express 1.x is limited to 250 MB/s. Clearly, a single-lane link cannot saturate the 6 Gb/s peak bandwidth of SATA 3.0 or 4.8 Gb/s ceiling specified for USB 3.0. Rated at up to 500 MB/s, a second-gen PCIe x1 interface is considered adequate.

Second-gen PCI Express is most often used in 16-lane links, giving the latest high-performance GPUs ample bandwidth. As far as we know, every mainstream platform offers at least 16 lanes, whether through the northbridge (AMD 785G, for example) or the processor itself (Intel's Core i3 and Core i5 CPUs). Enthusiast chipsets like AMD's 790FX and Intel's X58 Express offer (at least) twice this amount. Unfortunately, all other PCI Express lanes remain at 250 MB/s. There is an interesting difference, though, in how AMD and Intel handle this connectivity.

AMD vs. Intel?

For some reason, Intel's mainstream chipsets only support PCI Express 2.0 on the primary links that are used for graphics. This applies to both LGA 775 and LGA 1156 platforms. While Intel claims PCI Express 2.0 support for its LGA 1156 based PCH, it limits throughput to PCI Express 1.1-class performance. This is naturally a problem when we start looking at the latest high-speed motherboard-down controllers.

AMD, on the other hand, upgraded the link speeds on its 700- and 800-series chipsets, which means that current AMD mainstream and enthusiast chipsets don’t create bandwidth bottlenecks for high-speed add-on devices.

We took three P55 motherboards from Gigabyte and MSI that all come with different solutions to offer USB 3.0 and SATA 6Gb/s connectivity. We analyzed SATA performance using Crucial’s new RealSSD-C300 and a Seagate Barracuda XT with support for the third-gen standard and found that not all solutions deliver ample bandwidth.
Bottlenecks And Solutions For USB 3.0 And SATA 6Gb/s

All AMD 700 and 800 chipsets (both northbridge and southbridge) fully support PCI Express 2.0, while Intel’s PCIe 2.0 support is limited to the northbridge/processor-based interfaceThis is why it's unlikely you'll encounter bandwidth bottlenecks on AMD platforms.


once again AMD proves they are the only trustworthy pc hardware developer in existance.

and once again I bet this will never become mainstream info...

 

PCI Express 2.0 is pretty much unnecessary for anything but video cards. Devices like network cards, sound cards, video capture cards and other similar cards run just fine with a single lane of PCI-E 1.1 and could probably just run on normal PCI. Point is intel better tailored chiipsets that don't waste money and features they don't need, making it cheaper at least to produce (not sure if that actually means savings for consumers). I won't dispute the fact that it's NICE to have fully 2.0 lanes on AMD chipsets, but it hardly makes intel untrust worthy for making a difficult engineering decision.

Further more the article doesn't have any relevance to the issue at hand since PCI-E is full duplex, meaning each lane does the same speed down-link as it does up-link and can do con-current transfers. Although that may not have been why you posted that article, I feel like you're just trying to give intel a hard time.

 

Basicly you are accusing him indirectly as a fanboy, but instead of doing that, why don't you just prove him wrong? It is a more mature decision and will be informative for all the users here.

 

yeah sure cheaper to produce but not cheaper to buy, **** intel!!!!

 

I'm not taking cheap shots at intel, they have made choices in the past that hurt their name, I have no issue with them atm, but I sure as hell don't trust them.

I'm sick of being insulted and price gouged by greedy pos corp's.
I'll burn my money before I give it away to any company that can't live up to my standards F***them.


anyone notice how well that worked out for UBI ?insulting your paying customers, how out of touch with reality can they get?



the article I copied, I thought maybe offered some insight on this weird low bandwidth issue, that's my only agenda other than being wary of another rip off company.

I'm in no way a pcie expert, I'm no idiot either.

I think you seriously misjudged me, it's pretty freakin hard to not be offended.

side note: BTW I never have owned an AMD cpu.

 

Wow, did you stop reading directly at the red text or something?

I think my comment was taken out of context, I was simply trying to understand why you posted the article. To be honest I don't really care if I offended you or not as I don't even see how that's possible, it's a motherboard chipset, not your first born child. How bout you all settle the **** down for a second and get to grips with reality. We still don't even know if this issue is legit seeing as the only evidence comes from some shoddy tool that had a narrow focus to being with and probably isn't designed for the hardware we're using it on now.

 

do you seriously believe because you have a better understanding of pcie architecture you somehow are actually smarter than everyone else?

you have a long way to go man.....trust me it's out of your reach....(frankly. don't trust me I couldn't care less)

you clearly have a negativity issue from this superiority complex, that makes you read everything in the worst possible context, you need some help man......

you are nowhere near the level you think you are.

 

No I just think you guys are getting worked up over nothing and you can't even confirm the the information you've got are the facts, or that they have a statistically valid effect on performance. Go outside man, chill out and breathe in something real for a change.

I have a basic understanding, but it's enough to know that what you posted is irrelevant. Even then isn't the PCI-E architecture the whole focus of this thread? And would it not help to have someone who knows something about Bus architecture and how video cards work to help resolve this issue (if there even is an issue)?

What are these 'levels' you speak of? And who made you the authority to judge who's on what level? Let me put it this way, my profession is in both IT systems (hardware and software, I'm the IT Manager for a small research lab) and I'm also a Software Engineer (for the same research lab building 3D engines for mobile devices). I require basic/Intermediate knowledge of the concepts to get my work done. It may not give me a full blown understanding like that of an Electrical Engineer but it's enough.

I would rather an expert (not me) comes into the thread and sheds some real light on this issue so I can learn something new that works to my advantage. If I'm proven wrong then so be it, that's excellent, my knowledge of computers deepens, if not then it simply confirms my understanding.

That's a question for philosophy. If by smart you mean 'has better understanding' on the subject of the PCI-E architecture then yes, I believe having a better understanding of PCI-E architecture does give me a better understanding of PCI-E architecture. This is a tautology. If by smart you mean 'intelligent' then no, I don't believe that is the case as intelligence has many definitions and measures. While there are incredibly stupid people in the world there are still a lot of intelligent people, but they are intelligent by different measures and contexts. I always give people the benefit of the doubt in that regard.

 

Hello to everyone.

I haven't read every post here, from some point and afterwards it has become a little too technical for me. At least for now.

I registered because I experience exactly the same problem with the topic creator.

I just installed my second 6950 and tried Crysis Warhead.

With one 6950 I have 90% -99% GPU usage and 45 - 60 FPS
With two 6950s I have 50% GPU usage for both cards and exactly the same framerate.

My system is:

i5-750 overclocked to 3.6GHz
MSI P55-GD65 ( 2 pci-e slots, 16x/0x and 8x/8x)
2x2 GB Kingston HyperX at 1800MHz
Thermaltake 750W Toughpower QF

The only test besides Crysis Warhead that I did is 3DMark 11 which scales pretty good.

1 card: 4290
2 cards: 8290

Do we know the cause of the problem? I don't think an i5-750 @ 3.6GHz can be a bottleneck...

The driver I use is 11.1a

The cards are the new Sapphire 6950s with 1GB RAM (they can't be unlocked to 6970).

 

Hi,
I visit this forum constantly but had no need for posting.
I registered,also to try to contribute to solving this problem.
Having the same problem. Bought 2x XFX 6950's and scaling problem appeared big time.
My mbo is GB EP45-DS3R, other component's in specs. The board has one 8x and one 16x pci-e lane. In game CF scaling is terrible -> no performance gain, even in some ruining the performance (crysis warhead, metro 2033...). Heaven benchmark gaind about 50% -> from 50.1 FPS to 74.4 FPS.3DMark11 terrible-> from 4404 to 5047
Let's begin with my kind of trying to solve this problem so other's can eliminate the possibilities for trying to solve the same.
So first i reinstalled drivers (for all of them -> 10.12, 11.1, 11.1a , 11.2)-> nothing happens
Second,took one card from x16 pci-e lane leaving the other on x8 pci-e lane-> same performance as one on x16, no improvement in CF scaling (same crappy performance)
Tried all 4 possibilites and nothing happens.So the cards actually work with CF off.
Installed all the newest mbo drivers(chipset)-> nothing happens.
I am contacting the xfx support team so i'll update here if i come to a solution. Very possible i will return the second one, beacuse this far from scaling in review benchmarks.
PS. The cards are not unlocked, working at stock speeds.
PPS. The pci-e test is resulting ~2.3GB/s both ways. I really don't know wtf is with this problem.

 

your cpu bottleneck , pretty badly those cards.

 

I would understand this if i have in-game CF scaling about 5-10-15% and not let's say theoreticly 100 % performance gain, but i have scaling of 0% or less than that. This problem persists in-game, but the only scaling of 20% i saw is in heaven benchmark. This is very aqward and mind-numbing.