Friday, April 8th 2011

AMD Gaffe Has AIBs Ship Radeon HD 6790 with Too Many ROPs

A possible miscommunication between AMD and its foundry or board partners saw some, if not all partners ship AMD Radeon HD 6790 graphics cards with more ROPs enabled than specified. The HD 6790 SKU is originally specified to have 16 of the 32 ROPs on the 40 nm Barts GPU enabled, however, batches of GPUs shipped have 24 out of 32 ROPs enabled. While not a bad thing for the user at all (since the GPU ends up with more geometry crunching power at its disposal), it has AMD red faced, as it disturbs the product lineup.

The issue surfaced when GPU-Z started reading ROP count of our samples as 24, even as AMD press deck and subsequently the product page on AMD website mentioned HD 6790 ROP count as 16. We initially dismissed it as a GPU-Z bug, but as it turns out, HD 6790 indeed has 24 ROPs enabled, if GPU-Z reads so. An ROP (raster operations processor) handles a key part of the GPU's geometry rendering. ROPs process final shader output pixels and put them into memory. 24 ROPs theoretically gives these few HD 6790 cards 50% higher geometry processing power. This isn't the first time AMD fumbled with specifications. Some of the first AMD Radeon HD 4830 graphics cards shipped with 80 stream processors less than specification; more recently, some initial Radeon HD 6850 samples had all 1120 stream processors of Barts enabled. They're supposed to have 960. AMD said that it is investigating into the matter, and could make an official statement soon.

We have asked severals AIBs to test their production boards and they all have 24 ROPs so far.

Update: We have discussed this with AMD and it looks like this was our mistake and the cards really have 16 ROPs.

The register GPU-Z looks at to calculate the number of active ROPs indicates the number of disabled ROP units using set bits. For the case of HD 6790 two bits are set, which means two disabled units. The Barts GPU has a total of 32 ROPs in 8 units, which would leave us with 24 ROPs based on the register data: (8 [total ROPs] - 2 [disabled ROPs]) * 4 [pixels per clock per ROP] = 24.

If you look at the architecture diagram above (look for the thick black box or the red box), you can see that the shader units of the GPU are split into two shader arrays and the ROPs (yellow squares next to "L2 cache") are independent from these. In reality the ROPs are located inside these shader arrays, too. As a result "two deactivated ROPs" really means "two deactivated ROPs per shader array". So the correct shader count is (4 [ROPs per shader array] - 2 [disabled ROPs per shader array]) * 2 [shader arrays] * 4 [pixels per clock per ROP] = 16 !

Thank you AMD for clearing this up.
Add your own comment

52 Comments on AMD Gaffe Has AIBs Ship Radeon HD 6790 with Too Many ROPs

#1
theJesus
That would suck if you got one with 24 ROPs, but needed to RMA it and they sent you the normal 16 ROP one instead.
Posted on Reply
#2
btarunr
Editor & Senior Moderator
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
Posted on Reply
#4
btarunr
Editor & Senior Moderator
by: Jonap_1st
good news or bad news?
Mixed. It's good if you already have a 6790 or are going to get one and it turns out to have 24 ROPs. It's bad if you go on to buy a 6790 in hopes of getting 24 ROPs, and it has 16. AMD specifications say 16.
Posted on Reply
#5
mtosev
I like. So which brands have 24 ROPs? someone pls make a list
Posted on Reply
#6
Trackr
by: btarunr
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
That's not true.

The HD 6950s have a 98.6% chance of unlocking, and the CPUs are known to unlock almost as well, albeit with more effort.

And we have no idea what percentage of HD 6790s have 24 ROPs.

It's more of a "Shh, this card can unlock, but don't tell anyone", rather than a "Hey kids, come try out our GPUs and see if you get lucky".
Posted on Reply
#7
20mmrain
by: btarunr
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
Thought the exact same thing!!!
Posted on Reply
#8
slyfox2151
by: Trackr
That's not true.

The HD 6950s have a 98.6% chance of unlocking, and the CPUs are known to unlock almost as well, albeit with more effort.

And we have no idea what percentage of HD 6790s have 24 ROPs.

It's more of a "Shh, this card can unlock, but don't tell anyone", rather than a "Hey kids, come try out our GPUs and see if you get lucky".
they dont unlock..... they come with 24 ROPS already enabled. i would assume most if not all of the first stock of cards will be like this.


where did you pull the 98.6% number?

there is definetly a pattern with AMD releasing stunts like this.




"slyfox notices wizzard reading this thread and waits for his words of wisdom with anticipation."
Posted on Reply
#9
qubit
Overclocked quantum bit
Yeah, I'm with those who think that this is some unofficial marketing tactic from AMD. I think it's excellent and wish nvidia would make "mistakes" like this too. ;)
Posted on Reply
#10
slyfox2151
by: qubit
Yeah, I'm with those who think that this is some unofficial marketing tactic from AMD. I think it's excellent and wish nvidia would make "mistakes" like this too. ;)
acidently 3 GPUs on the GTX 580 :P

oh i can dream.
Posted on Reply
#11
95Viper
by: btarunr
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
yep:toast:

This marketing scheme works for the lottery here.
By a ticket take a chance, you may hit a winner.
People, love to gamble on a chance at being the winner.
So, why not draw on that characteristic.
I got a 6950 that unlocked... I am a winner!:cool:
Posted on Reply
#12
qubit
Overclocked quantum bit
by: slyfox2151
acidently 3 GPUs on the GTX 580 :P

oh i can dream.
And 800W power consumption! :roll:
Posted on Reply
#13
meirb111
by: btarunr
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
reminds me of joke about a man that find his wife with another man
the other man says it an accident i slipped and fell on her breast
Posted on Reply
#14
CharlO
Please back up that bios!

AMD lucky marketing is the best one ever!
Posted on Reply
#15
NC37
AMD is turning into one of those Japanese anime ball machines. Never know which one you'll get..."Ooo come on 24 ROPS!! Aww just a stock model..."

Only thing missing is they don't come with scantily clad top heavy school girls...yet *hint* *hint*

Actually that would put new demand into the GPU market. Buy a new AMD GPU, get a special collectors edition Ruby action figure! She overclocks high kids!! Collect all and trade with your friends!! :D
Posted on Reply
#16
Jonap_1st
by: btarunr
Mixed. It's good if you already have a 6790 or are going to get one and it turns out to have 24 ROPs. It's bad if you go on to buy a 6790 in hopes of getting 24 ROPs, and it has 16. AMD specifications say 16.
if AMD redesign it to "true" 16 ROPs , then it will be really bad news.. :laugh:

i'll stick my trust to reviewers.
Posted on Reply
#17
W1zzard
by: CharlO
Please back up that bios!
the rop config is not controlled by bios on these cards, i already checked
Posted on Reply
#18
unsmart
So if the first batch where all 24 then the reviews are all bunk, right:p now thats marketing!!
Posted on Reply
#19
mamisano
How much will performance suffer when the 16 ROP cards are released?
Posted on Reply
#20
mdm-adph
Seems to be par for the course for AMD/ATI -- what I wonder is: has Nvidia ever done anything like this (since back in the GF 6800 days)?
Posted on Reply
#21
Arrakis+9
by: btarunr
Now more people will buy HD 6790 in hopes of "getting what they're not supposed to get". Gotta love AMD's "accident marketing".

"Oops, some cards have too many ROPs, buy a card, and get lucky"

"Oops, some HD 6950 can be flash to HD 6970, get lucky"

"Oops, some dual-core/tri-core CPUs can be unlocked to quad-core, buy one, get lucky"

It doesn't take CIA to see a pattern.
that certainly does work for them. much better than any of intel or nvidia's marketing :laugh:
Posted on Reply
#22
antuk15
I thought AMD said that this core couldn't be 'Unlocked' like the 6950 can.

Looks like it might actually be possible on some cores.
Posted on Reply
#24
W1zzard
by: antuk15
I thought AMD said that this core couldn't be 'Unlocked' like the 6950 can.

Looks like it might actually be possible on some cores.
no, there is no unlocking potential. you could downgrade the rops to 16 or less in theory making the card slower.

but going from 24 to 32 rops is not possible, those are properly locked in hardware
Posted on Reply
#25
Bjorn_Of_Iceland
thats some psychological application in marketting right there. Already was having doubts even way back to amd quad unlocking.
Posted on Reply
Add your own comment