AMD's Bobcat and Bulldozer

[ajaidev]

Or they dont have a clue ^^
I explained it above what AM3+ probably is about .. only a new package, not a new socket (besides higher RAM clocks).

It must be something like that otherwise the AM3+ should be called AM4. More info is needed on the bulldozer and its socket, i did not see anything about it on anandtech.

Its very sad if bulldozer is not compatible with simple AM3 socket because it will force people to buy new mobos and force them to choose between Sandy bridge and Bulldozer.

[mAJORD]

Agree that's not good for a AM3 actual board.

But C32 and G34 will be working.

i don't understand fully this part in anandtech review :



Why a 2 Alu core could be faster than a 3 ?




WTF if there is not 4 alu and 3 agu per core, where is integer performance ?

I'm afraid about this too :

Core 2 through nehalem (not sure about SB) has 3 ALU , 2 AGu, does it have less performance than K10? At this point, without more details I think it's hard to say if this is really an 'issue' or not. for single threaded performance

[Opteron146]

You don't need to tell me what AM3+ is about.

Maybe not u, but them

I think it's very unlikely that their knowledge about AM2/+ and AM3 is so limited that they honestly believe that an AM2 processor will work in AM3+.

Then they would not have written it ...
For a type that kind of error is too big. They definitely mixed up some facts.

Instead of:

AM2 and AM3 processors will work in the AM3+ socket, but Bulldozer chips will not work in non-AM3+ motherboards.

It should be:

AM3 processors will work in the AM3+ socket, but Bulldozer chips will not work in non-AM3 motherboards like AM2.

Not much difference, but more than a typo

[superrugal]

[ajaidev]

http://www.tomshardware.com/reviews/...hips,2724.html


Another one

[-Boris-]

Lost Circuits :



ExtremeTech :



I don't understand what Lost Circuits's words means

It just means that a AM3+ CPU won't work in an AM3 board. But an AM3 CPU will work in an AM3+ board.

And that both sites are claiming the same thing. It suggests that extremetech do have a clue, but typoed about the AM2 part.

[onethreehill]

"Bulldozer" 20 Questions, Round One

You’ve sent in your questions and we’ve begun to sort through them to pull out the best. There were plenty of common themes that were arising, so we’ll be grouping some of the bigger categories together. I am going to tackle some of the easiest ones first because some of the more technical questions will need to go to the engineers.

We’ll handle this blog in four rounds, with 5 questions each.

http://blogs.amd.com/work/2010/08/23...ons-round-one/

[-Boris-]

Maybe not u, but them

Then they would not have written it ...
For a type that kind of error is too big. They definitely mixed up some facts.

Instead of:
It should be:
Not much difference, but more than a typo

You don't need to add "like AM2" at the end, just delete the AM2 in the beginning of the sentence and it makes perfectly sense.

We have two sources saying that Bulldozer won't work in non-AM3+ motherboards. What's the problem?

[Opteron146]

You don't need to add "like AM2" at the end, just delete the AM2 in the beginning of the sentence and it makes perfectly sense.

No you also have to delete the second "+" in my opinion, because it makes no sense otherwise ;-)
Otherwise, as ajaidev said, it should be named AM4, not AM3+.

The "like AM2" is then there to stress the difference to current AM3 CPUs, which are able to work in AM2 sockets.

[Opteron146]

We have two sources saying that Bulldozer won't work in non-AM3+ motherboards. What's the problem?

Oh, where is the 2nd one ? Did I miss a post, while writing ?
The problem is that the sources are not logically, and that you can find more misinformation on the net than real information ...

Before I believe something I am very critical and questions the reasons.
In that case: I dont see a reason, and the 2nd site (havent checked it yet), probably just copy/pasted from the first one. That is typical for the internet ;-)

Just wait a bit, and there may be even a 3rd or 4th site. However, the argumentation is not any better.

[-Boris-]

No you also have to delete the second "+" in my opinion, because it makes no sense otherwise ;-)
Otherwise, as ajaidev said, it should be named AM4, not AM3+.

No, AM3 cpus work in AM3+, besides, the number at the end suggest what typ od memory it uses. Bulldozer must be some kind of AM3, not AM4. And since two sites claims that Bulldozer won't work in AM3 boards I think that there is something to it.

[Olivon]

http://www.tomshardware.com/reviews/...hips,2724.html


Another one

Thanks ajaidev

The company has already confirmed that it’ll maintain socket compatibility with existing Magny-Cours-based Opteron processors. Thus, you can expect to see Bulldozer-based CPUs dropping into existing server boards and, likely, Socket AM3 desktop platforms as well.

[ajaidev]

Bulldozer: One of two new x86 architectures, Bulldozer will be used in performance desktops and servers. Bulldozer-based modules will serve as the basis for AMD’s next generation of processors. The company has already confirmed that it’ll maintain socket compatibility with existing Magny-Cours-based Opteron processors. Thus, you can expect to see Bulldozer-based CPUs dropping into existing server boards and, likely, Socket AM3 desktop platforms as well. AMD’s target power use for Bulldozer-based chips is between 10 and 100 W.

http://www.tomshardware.com/reviews/...ps,2724-4.html

My god now they say drop in's for "Socket AM3 desktop platforms" not only AM3+. People are confused and confusing others

[fellix_bg]

WTF if there is not 4 alu and 3 agu per core, where is integer performance ?

I'm afraid about this too :


Core 2 through nehalem (not sure about SB) has 3 ALU , 2 AGu, does it have less performance than K10? At this point, without more details I think it's hard to say if this is really an 'issue' or not. for single threaded performance

K8 and K10 arch could never reach the full potential of the 3-issue pipeline due to fundamental limitations. Bulldozer is simply streamlining the concept and optimizing other parts to gain efficiency -- i.e. more with less, relatively speaking.

[Opteron146]

No, AM3 cpus work in AM3+, besides, the number at the end suggest what typ od memory it uses. Bulldozer must be some kind of AM3, not AM4. And since two sites claims that Bulldozer won't work in AM3 boards I think that there is something to it.

I found the 2nd source now. That one is bogus, too. Lostcircuit wrote:

Backwards Compatibility

All Bobcat and Bulldozer enabled motherboards based on the AM3+ socket will be backwards compatible with earlier AMD AM3 CPUs but AM3 CPUs will not be a drop-in replacement for existing processors in existing motherboards.

They wrote AM3 .. not AM3+
So literally, they mean that I cannot use my X4 965 in old AM2 boards.
Surely, that is probably not what they meant, but that is what they wrote.

All in all we now have two sites which both seem to have hurried to get their articles online in time and therefore didnt check them thoroughly. Hence I dont take any of them for granted and I will wait for an updated / clarified version.
I agree on Olivon's view, I also dont get what Lostcircuit is saying. Maybe they want to say that AM3+ CPU are incompatible to existing boards ... but maybe they just misunderstood it, too.

[-Boris-]

I will be very disappointed at them if they misunderstood the compability so gravely. But it seems like some of them already are proven wrong, one suggests 4 Phenom II like ALU/AGUs, and some suggest 2 AGU and 2 ALU.

[-Boris-]

I found the 2nd source now. That one is bogus, too. Lostcircuit wrote:


They wrote AM3 .. not AM3+
So literally, they mean that I cannot use my X4 965 in old AM2 boards.
Surely, that is probably not what they meant, but that is what they wrote.

All in all we now have two sites which both seem to have hurried to get their articles online in time and therefore didnt check them thoroughly. Hence I dont take any of them for granted and I will wait for an updated / clarified version.
I agree on Olivon's view, I also dont get what Lostcircuit is saying. Maybe they want to say that AM3+ CPU are incompatible to existing boards ... but maybe they just misunderstood it.

The sentence don't make any sense at all if they actually mean AM3 (non+), since existing CPUs are AM3. It has to be AM3+ as replacement for AM3.

And I agree that they aren't clear, and are either wrong about the compability, or they have lousier grammar than me.

Old information says that BD will work in AM3. But we don't know if anything has changed.

[Opteron146]

The sentence don't make any sense at all if they actually mean AM3 (non+), since existing CPUs are AM3. It has to be AM3+ as replacement for AM3.

Yes it has to be, but as long as there is no confirmation, you cannot take that for 100% sure. Maybe they really gravely misunderstood it, because they are caught in a AM2, AM2+, AM3, AM3+ confusion

Let's wait and see and let's not panic for now. It will be probably clarified in a few hours anyways.

Edit:
To the performance discussion:
2 ALUs probably wont have the same INT performance as Sandy Bridge, however, they could clock higher ;-)
As long as the power consumption would not be as bad as Pentium4's, I wouldnt have a problem with that

Furthermore, if you mix in FP code, it becomes favorable for AMD, because of the additional 4 FP ports. Intel CPUs are sharing the INT and FP ports, i.e. the max. throughput is limited to 3 Ops, either pure INT or pure FP or INT/FP mixed. If there is only 1 FP instruction, or not more than 2 INT instructions, then the AMD approach has no disadvantage.

Hans de Vries once wrote that 9x % of code could be processed easily with a 2issue core. That fact is proven now by AMD's recent statement, that the 3rd INT ALU was not used often. Intel tried to use their 3 pipes by introducing SMT, AMD now just cut away the 3rd ALU and added in a 2nd INT core, dedicated to a 2nd thread.

Due to less complexity in every core, clocks could be higher (there are some scientific papers, found by Dresdenboy about that topic, check his blog if you want to know more), so all in all, it should be the better approach - well at least as long as we dont speak about Pentium1 class like performance for a single core

[Chrono Detector]

AMD pulling an Intel here, you buy a new CPU, you need a new board.

Guess its a way to make more money, I suppose, I would have bought a new board and chipset that fully supports Bulldozer anyway. I never really believed in the idea of putting a newer CPU in an older board, as there may be limitations.

[ajaidev]

I am speculating that n+1 module bulldozer vs n+1 core sandy bridge will be on the table this is because of two things:

I have not heard about anything above 8c for sandy bridge even in server space this was 3 months ago. The top line sandy bridge CPU is suppose to be a 8c with 16t and the top end bulldozer is suppose to be a 8 module 16t cpu. Now i know sandy bridge is super ultra flexible and more cores may be possible but on 32nm i dont think so.

The other thing is that the performance speculation "33% more cores and 50% more performance" is pretty good but this does mean that single module != single K10.5 core. The bigger picture is not the more core's but the die size. 50% more performance on same lower die size and you got a winner, if you look at it in a different angle you can say its really 8 modules vs 12 cores.

[xlink]

so basically we're in a core war and AMD is making a chip where each core is 2/3rds of what it used to be and shall be marketting by the number of cores...

this sounds like the GHz race all over...

[mAJORD]

K8 and K10 arch could never reach the full potential of the 3-issue pipeline due to fundamental limitations. Bulldozer is simply streamlining the concept and optimizing other parts to gain efficiency -- i.e. more with less, relatively speaking.

Sorry, that was not me who said that , I misplaced the quote tag.. Fixed, and I agree

[Kuroimaho]

http://www.extremetech.com/article2/...2368186,00.asp

waaa waa

Unlikely.
Phenom 2 works in my old mobo with 690 chipset, NB at 2400. I expect less tweaking options on AM3 mobos with Bulldozer but if the mobo maker makes updated Bios it will work.

[ajaidev]

http://www.techpowerup.com/129392/AM...hitecture.html

Another one

Because of this design change, Bulldozer processors will come in totally new packages that are not backwards compatible with older AMD sockets such as AM3 or AM2(+).

waaa waa

[-Boris-]

AMD pulling an Intel here, you buy a new CPU, you need a new board.

Guess its a way to make more money, I suppose, I would have bought a new board and chipset that fully supports Bulldozer anyway. I never really believed in the idea of putting a newer CPU in an older board, as there may be limitations.

I'm sure AMD wouldn't ditch AM3 compability without a good reason. Might have to do with turbo and power circuits. But as we already pointed out, we don't know anything yet, since not one of the previews mentioning ditched AM3 compability have been able to produce an intelligible sentence about the matter.