Ati HD 5970 running slower than ussual?

[Dent1]

Iv decided on not getting the HD 6990 as its not worth it. I have purchased a HD 7970, but its going to take upto 3 weeks to arrive.

The HD 5970 are working fine, I think its driver issues mainly as Crysis seems to work perfectly just some games that give stutter. But lowering the graphics quality does help but looks crappy lol..

I think ill wait for the HD 7970 and see how that goes.

The HD 7990 is 2x HD 7970's right? So crossfiring it later would be a good route to go?

Thanks

Crossfire is always hit and miss for some.

For me I've always had great luck with CF, good scaling, no stutter or driver issues. But then you get other guys on here whom will convince you it's plagued with problems. If you have a CF board and a second card becomes cheap in a couple of years sure why not.

Again. Keep in mind @ 3600x1920 is an unrealistic resolution. Most reviews don't even benchmark that high. Personally I'd settle for a less more humble resolution like 1920x1080 if it means the GPU will last a few years longer without constant upgrades. These cards are not exactly cheap.

Also keeping your Intel i5 2400 @ Stock is restricting a lot of performance. You'll get more from your 5970 or new 7990 if your able to clock it higher. These CPUs an hit 4-5GHz area with relative ease.

 

[chaseace]

The only issue is that I think HD 5970 crossfire would be too juicy on power, i dont know if my TX850W psu will be able to handle it. I mean on the website link below I think it said I required 799W, but obviously thats minimum and im just a little over it. Overclocking would probably burn out the PSU and my bills lol..

I was happy with 1920x1080, but then when I seen the eyefinity I went and purchased 2x 24" relatively cheap..thus why I thought if i can use these then it would be great. I doubt ill buy the 7990 but 7970 is a possibility as I can get around £300 for these two cards..

http://extreme.outervision.com/psucalculatorlite.jsp

I can easily overclock but I want to get a finalized system which is decent, then overclocking to give it that extra boost.

Thanks

 

[crazyeyesreaper]

even if you crossfire the 5970 with a5870 or another 5970

thats means going from 5970 = 2 gpus already to 3 gpus top 4 gpus scaling after 2 gpus is pretty much garbage your limited to 1GB of vram no matter what and sorry to say most games today use over 1gb at 1080p alone throwing more GPUs at that problem wont solve it Single 7970 is the best option

I had 5850 xfire 6950 xfire 6970 xfire and a 7970, 7970 is the only logical option in this regard.

 

[Dent1]

even if you crossfire the 5970 with a5870 or another 5970

thats means going from 5970 = 2 gpus already to 3 gpus top 4 gpus scaling after 2 gpus is pretty much garbage your limited to 1GB of vram no matter what and sorry to say most games today use over 1gb at 1080p alone throwing more GPUs at that problem wont solve it Single 7970 is the best option

I had 5850 xfire 6950 xfire 6970 xfire and a 7970, 7970 is the only logical option in this regard.

I agree with this but I think it needs to be taken with a pinch of salt.

I haven't seen much evidence to suggest 4 GPUs are garbage - although I would agree scaling would become less effective.

1GB of VRAM isn't the end of the world, as long as their is enough physical RAM and the throughput is reasonably fast.

For example @ 2560x1600, the 2GB GTX680 scores exactly the same as the 3GB 7970.

The 2GB GTX680 is only 8% slower than the 4GB 6990. This emphasises that VRAM is important but ultimately if the GPU is good it will perform well regardless.

http://tpucdn.com/reviews/ASUS/HD_7970_Matrix/images/perfrel_2560.gif

 

[crazyeyesreaper]

And yet games like Shogun 2 auto turn down in game settings automatically when a vram limit is hit, Some games like GTA IV without enough vram it doesnt let you max settings

Skyrim with mods without enough vram the game will drop to 1 fps then jump to 30-60 then back to 1 fps.

It seems Battlefield actually has better image quality with more vram available to a certain extent/ at max settings at 1920x1080 for example many games may report 1500mb of usage in reality they may only need 1000mb to run fine. however you will experience texture pop in on occassion, FPS drops as data loads into the GPU etc. These all come into play

and sorry to say scaling on the 5000 series was just plain OKAY it wasnt stellar.

2x 5850x = 5970. scaling on average was around 50% scaling with a 3rd GPU was less than 25% and a fourth GPU added 0% unless running insane resolutions. heres the problem Eyefinity on those older cards was a complete joke. and 1GB of vram is not enough to run the OPs resolution that hes looking for which is 3600x1920

at that resolution 1GB of vram is not sufficient end of story and 4 5800 series GPUS in tandem wont be enough.

5970 Quad Crossfire

Crysis

So again adding more 5800 series GPUs to the mix wont magically improve his GPU performance It will just add a bunch of headaches
because the games hes trying to play dont even support Crossfire properly in the first place when comes to Assassin Creed so 4x GPUs = 600-700w power draw on the GPUs alone for Zero benefit, Then there NFS which is a terrible port Crysis runs well enough but 4x GPUS vs 2x GPUs offered next to nothing performance wise and at higher resolutions or multiple screen had crashing issues.

So overall the 7970 is the only possible option thats current and isnt a complete waste of money.

Also 4GB 6990 did you forget VRAM isnt ADDED TOGETHER the 6990 = 2gb usage vram each gpu gets a buffer of 2GB marketing calls it 4GB but its not.

 

[Dent1]

That is because some games hit a frame rate wall, crossfire or no crossfire.

You have to keep in mind the 5790 was a high end card on release, still faster than a lot of cards today. A lot of games including Crysis was unable to stress out a single 5790 let alone two in CF. You'd have to start benching more modern and demanding games to see how CF fairs.


That relative performance chart is misleading too. Because on half of the titles the 5790 in CF was getting between 40%-100% boost. It just seems lower because it's averaged with the other half of the results where CF didn't help. So there is a 50% chance CF won't help and 50% chance you'll get a 40-100% performance boost. Those are great odds if you're picking up a second hand card. Bear in mind this is with immature drivers and on old games that couldn't stress out a single 5970.

On single PCB cards the memory total is the total.

The 6990 should be 4GB total, understandably the 6990 in CF wouldn't be 8GB. But its definitely 4GB as advertised.

But I agree it probably isn't the best idea PSU wise. These things are just too power consuming!!!!!

 

[crazyeyesreaper]

no the 6990 is 2x 6970 GPUS each gpu as 2gb of vram the usable amount of vram is 2gb thats it. Thus games can only use 2gb out of the 4 thats on the card.

In marketing they go by the amount ON the PCB not the amount the GPU can use.

so the 5970 is marketed as 2GB but only 1GB is usable
6990 is marketed as 4GB but only 2GB is usable.

 

[Dent1]

no the 6990 is 2x 6970 GPUS each gpu as 2gb of vram the usable amount of vram is 2gb thats it. Thus games can only use 2gb out of the 4 thats on the card.

In marketing they go by the amount ON the PCB not the amount the GPU can use.

so the 5970 is marketed as 2GB but only 1GB is usable
6990 is marketed as 4GB but only 2GB is usable.

That can't be right because that is false advertisement. It's like saying here is a 20" screen but only 10" is viewable.

I understand that 2GB is split between two GPUs, but on a single PCB card I don't think the data is mirrored or duplicated as per traditional CF. Otherwise wouldn't it be cheaper not to put the extra 2GB on the card and save on production cost?

 

[crazyeyesreaper]

It is mirrored because xfire etc isnt special to the 6990 or 5970.

It is what it is and its the truth.

 

[Dent1]

no the 6990 is 2x 6970 GPUS each gpu as 2gb of vram the usable amount of vram is 2gb thats it. Thus games can only use 2gb out of the 4 thats on the card.

In marketing they go by the amount ON the PCB not the amount the GPU can use.

so the 5970 is marketed as 2GB but only 1GB is usable
6990 is marketed as 4GB but only 2GB is usable.

It is mirrored because xfire etc isnt special to the 6990 or 5970.

It is what it is and its the truth.

Again, wouldn't it be cheaper not to put the extra 2GB chip on the card and save on production cost? Surely AMD don't like wasting money on unnecessary components?

Also I've hunted through the official AMD Radeon HD 6990 specification page and it says 4GB GDDR5 Memory. Surely if 2GB was unusable it would say so in the small print otherwise they'd get sued or investigated by trading standards?


Sapphires, Gigabytes and MSI website don't state only 2GB is usable in the small print. So I'm going on a limb and saying you are wrong unless you have a good source which says otherwise.

http://www.amd.com/uk/products/desk...6990/Pages/amd-radeon-hd-6990-overview.aspx#3
http://www.msi.com/product/vga/R6990-4PD4GD5.html
http://www.sapphiretech.com/presentation/product/?cid=1&gid=3&sgid=1041&lid=1&pid=1114
http://ee.gigabyte.com/products/page/vga/gv-r699d5-4gd-b/specs/

 

[crazyeyesreaper]

God I hate dealing with morons that dont understand multi gpu tech.

just because theres a single PCB doesnt mean its addative

a 5970 is two 5870s end of story just as the 6990 is 2x 6970s

its 2x GPUs on a single PCB thus why review specs always show 2x XXXX for the specs

Bit Tech review

As with previous AMD dual-GPU cards, the basis for the card is two top-end GPUs – it uses the same Caymen XT GPUs found in (single-GPU) HD 6970 2GB cards. However, the two GPUs operate at lower frequencies than the HD 6970. With the HD 6990 4GB, this means the 3,072 stream processors run at 830MHz rather than 880MHz. Similarly, the 4GB of GDDR5 memory (2GB per GPU) is clocked at 1.25GHz (5GHz effective); roughly 9 per cent lower than the 1.375GHz (5.5.GHz effective) memory clock speed of the HD 6970 2GB.

TPU review:

In comes the Radeon HD 6990, the very peak of AMD's Northern Islands family of GPUs. It carries the codename "Antilles", and is a dual-GPU graphics card making use of two of AMD's "Cayman" graphics processors. Cayman in its single-GPU board designs make up for the rest of the HD 6900 series, namely HD 6950 and HD 6970. On AMD Radeon HD 6990, the Cayman chips have all 1536 of their stream processors based on the VLIW4 design enabled. Each GPU is backed by 2 GB of fast GDDR5 memory over a 256-bit wide memory interface each, totaling to 4 GB of total memory, the highest for a reference consumer graphics card launch.

http://www.techpowerup.com/reviews/ASUS/Radeon_HD_6990/

Litterally even tho everything is on the same god damn PCB its still 2 seperate friggin GPUs it has 0- difference between it and 2x single gpus in crossfire the only difference is the use of a PLX chip that acts as link between the GPUs on the single PCB.

Did you not find it odd that if the 5970 was truly 2 usable gigs and the 6990 was usable 4gb that people would keep opting for 2gb cards which bought in tandem cost the same?

6990 has only 2gb usable memory this limitation applies to every GPU in Crossfire or SLI it is VRAM IS NEVER ADDED UP you are limited to the amount per GPU.

7990 = 6gb but its 3gb per GPU 2x 7970 = 6gb but only 3gb is usable
6990 = 4gb but its 2gb per GPU 2x 6970 = 4gb but again only 2 is usable
5970 = 2gb but its 1gb per GPU 2x 5870 = 2gb as well but again only 1 is usable


I mean it should be rather obvious you can Crossfire mixed memory cards but are limited to the vram of the card with the least amount so a 7850 1GB can Xfire with a 7850 2GB but only 1GB is usable. This has been true since the dawn of modern Crossfire and SLI.

aka total Vram is limited due to data being mirrored so just as you have 2x 5850s in crossfire if you load GPU-Z and load a game its only gonna use up to 1GB you dont add the memory to get the total. The same holds true to single PCB dual GPU solutions.


EDIT found it finally:
http://support.amd.com/us/kbarticles/Pages/ATICrossFire_comp_req.aspx

Q: Does ATI CrossFire™ technology double the memory?
A: No, ATI CrossFire™ technology does not double the memory, If you have a 512MB card, adding another 512MBcard will not increase your total memory to 1GB; it still will be 512MB.

thus the 6990 thing being close to a 680 has nothing to do with memory its just pure GPU grunt. the 680 and 580 were not a huge performance jump it was big but not as big as say 2x cards same holds true for the 6990 and 7970 2x older cards still did very well depending on the title. thus why the 590 / 680 6990 / 7970 are fairly close depending on the benchmark because the GPU performance increase from that gen to now is roughly the same as the overall average scaling of a great deal of games.

Anyway this is a pointless waste of my time to provide accurate information.

 

[Dent1]

Everything you said just proved my point.


Quote:

As with previous AMD dual-GPU cards, the basis for the card is two top-end GPUs – it uses the same Caymen XT GPUs found in (single-GPU) HD 6970 2GB cards. However, the two GPUs operate at lower frequencies than the HD 6970. With the HD 6990 4GB, this means the 3,072 stream processors run at 830MHz rather than 880MHz. Similarly, the 4GB of GDDR5 memory (2GB per GPU) is clocked at 1.25GHz (5GHz effective); roughly 9 per cent lower than the 1.375GHz (5.5.GHz effective) memory clock speed of the HD 6970 2GB.

All Bit Tech says is it runs 2GBs per GPU, 4GB total. It doesn't say only 2GB is useable.



TPU review:

Quote:
In comes the Radeon HD 6990, the very peak of AMD's Northern Islands family of GPUs. It carries the codename "Antilles", and is a dual-GPU graphics card making use of two of AMD's "Cayman" graphics processors. Cayman in its single-GPU board designs make up for the rest of the HD 6900 series, namely HD 6950 and HD 6970. On AMD Radeon HD 6990, the Cayman chips have all 1536 of their stream processors based on the VLIW4 design enabled. Each GPU is backed by 2 GB of fast GDDR5 memory over a 256-bit wide memory interface each, totaling to 4 GB of total memory, the highest for a reference consumer graphics card launch.

Again, the TPU review supports what Iam saying too. 2 GBs of GDDR5 per GPU. It doesn't say 2GB is unusable.

http://support.amd.com/us/kbarticles..._comp_req.aspx

Q: Does ATI CrossFire™ technology double the memory?
A: No, ATI CrossFire™ technology does not double the memory, If you have a 512MB card, adding another 512MBcard will not increase your total memory to 1GB; it still will be 512MB

AMD are referring about ATI CrossFire™ as a patented technology in the context of two separate physical cards on two bus lanes. It doesn't specify multi GPU PCB. So this quote can't be applied to support your cause.

Think of it logically. AMD are there to make money. Why would they put 2x2GB memory chips on a 1x card, when they could put just 2GB and save money. Obviously that extra 2GB is working and fully functioning.

 

[Deleted member 24505]

If they just put 2gb on the card, each GPU would only have 1gb to use. The memory on the card is the frame buffer, each gpu needs its own frame buffer. that is why with 2x2gb each GPU has a 2gb buffer, not 4gb in total.

If it was a single card with 4gb on t, it would have a 4gb buffer.

 

[Dent1]

If they just put 2gb on the card, each GPU would only have 1gb to use. The memory on the card is the frame buffer, each gpu needs its own frame buffer. that is why with 2x2gb each GPU has a 2gb buffer, not 4gb in total.

If it was a single card with 4gb on t, it would have a 4gb buffer.

So if your saying the memory is a frame buffer, that the memory is being used? correct.

 

[crazyeyesreaper]

yes but no game can use the 4gb its still only 2gb

it mirrors it

think of it like Raid 1 just because you have 2 x 1TB drives in Raid 1 means physically you have 2 TB of space but its really only 1TB due to it being mirrored

This is kind ahow VRAM works in Crossfire there may be 4gb on the card but 2GB is usable because the other 2GB for the second GPU has to mirror the EXACT SAME DATA

essentially 2 x 2048mb GPU 1 cannot have 1 set of data while GPU 2 has another set of data. If that was the way multi gpu worked then yes all 4gb would be used. However due to the data needing to be an exact copy for BOTH GPUs means effectively only 2gb of vram is actually usable due to the data needing to be mirrored over

So in terms of Skyrim with mods for example you could never actually use 4GB of memory

a 6990 would hit the wall at 2gb and end up with purple textures and crashes and frame rate dropping to 1 FPS.
mean while a 7970 3GB or GTX 680 4GB could increase to 3072MB of Vram usage before hitting that limit while 4gb card could hit 4096 etc etc.

a Dual GPU card has an EFFECTIVE vram of half of its total

So the 6990 being 4GB = 2GB effectively used
5970 is 2GB = 1GB used

so on and so on

Thus a 6990 and a GTX 680 2gb would hit the same VRAM limitation in the same games.

 

[Deleted member 24505]

So if your saying the memory is a frame buffer, that the memory is being used? correct.

yes, there are 2 gpu's on your card, each gpu has its own buffer, so the total buffer is split into 2, 1/2 for each gpu. so 4gb would be 2gb for each gpu, not 4gb total.

 

[crazyeyesreaper]

Thus the 4GB number is not false marketing because physically the card HAS 4GB of memory on it they just don't specify how its used and again Crossfire isnt magically different between 2 physical cards or dual gpu card they function exactly the same.

 

[Sir B. Fannybottom]

It should be showing 4 gigs, maybe one of your cards is broken. You should try to RMA it

 

[erocker]

Unfortunately VRAM is linked to its GPU, even on dual GPU cards. It would be nice if AMD could get the GPU's to go through the PLX chip first so the system just views it as one "GPU" and combine the VRAM but that just isn't the case right now.

 

[Dent1]

yes, there are 2 gpu's on your card, each gpu has its own buffer, so the total buffer is split into 2, 1/2 for each gpu. so 4gb would be 2gb for each gpu, not 4gb total.

Thus the 4GB number is not false marketing because physically the card HAS 4GB of memory on it they just don't specify how its used and again Crossfire isnt magically different between 2 physical cards or dual gpu card they function exactly the same.

IMO, if there is 4GB physically installed for textures and frame buffer then it's a legitimate 4GB card.

The way the tasks are divided between the two GPUs for frame buffer and textures isn't my concern. The important thing its doing something and isn't a redundant piece of component which I thought you were implying earlier.

Unfortunately VRAM is linked to its GPU, even on dual GPU cards. It would be nice if AMD could get the GPU's to go through the PLX chip first so the system just views it as one "GPU" and combine the VRAM but that just isn't the case right now.

Do you think its in the works? Maybe they've worked out it would cause my issues and opted out.

 

[erocker]

Do you think its in the works? Maybe they've worked out it would cause my issues and opted out.

I don't have a clue. Wishful thinking I suppose.

 

[Stanley85]

Dedicated PCIe PSU Cable

Hi,

I am not sure if this may help you out, but I expierenced a heavy difference by changing the wires that were attached to my 7870. Before I had used the two 6pins (leaving the additional 2 pin spared) that were hard attached to my PSU - by now I guess these were reserved for the CPU or something else and are not capable of fully give power to a PCIe VGA adapter.

By changing to the output stating PCIe on my cable-select PSU with a dual 6pin adapter my problems were gone. The fans of my card were spinning before but now the temp control seems working the first time. I can hear the fans speeding up etc. The performance now is at the levels where I had expected them... also I guess the card before used to much power on the PSU line attached and that slows down everything and causes bluescreens, freezes adapter loss and recover etc.

I hope this may help
Greetings Stanley