AMD Details Upcoming Bulldozer Architecture

Vigile writes "AMD is taking the lid off quite a bit of information on its upcoming CPU architecture known as Bulldozer that is the first complete redesign over current processors. AMD's lineup has been relatively stagnant while Intel continued to innovate with Nehalem and Sandy Bridge (due late this year) and the Bulldozer refresh is badly needed to keep in step. The integrated north bridge, on-die memory controller and large shared L3 cache remain key components from the Athlon/Phenom generation to Bulldozer but AMD is adding features like dual-thread support per core (but with a unique implementation utilizing separate execution units for each thread), support for 256-bit SIMD operations (for upcoming AVX support) all running on GlobalFoundries 32nm SOI process technology."

Comments

Not much new information

[kg8484]

Compared to such articles as AnandTech's coverage of this in November 2009, I don't see much new information. Perhaps the key bit, and this is glossed over but you can tell from the slides AMD gave them, is the difference between the bulldozer and bobcat cores. The bulldozer cores contain the two integer units that have been revealed before, but the bobcat core only has one but it still implements hyperthreading.

Re:Not much new information

[Rockoon]

Just to be clear, when you say "integer units" you mean "integer schedulers" and not actual integer execution units, of which even the old Athlon's had 3 per core (and that hasnt changed since then.)

Unlike Intel design, with highly asymmetric execution units, AMD's have had 3 symmetric integer execution units per core since the original Athlons. Its actually a pleasant breeze to write hand-optimized integer code on AMD's.

This new design looks (in the diagram) like it actually has 4 symmetric integer execution units per integer scheduler, with the bulldozer having 2 schedulers per core while the bobcat only having 1 per core (I would guess that the logical cores are alternated on rise-and-fall states of the clock on the bobcat, and the diagram certainly makes it look like that is the case.)

Each seem to have two wide floating point execution units, so the floating point performance of both bulldozers and bobcat's are probably equivalent.

What I think AMD has done here is that with the bulldozer, in integer performance it is going to behave like it has 2x the number of real cores. So an 8 core (16 thread) chip will perform much like an 8 core CPU in floatng point work, but much more like a true 16-core CPU in integer work. This should give it a large advantage over Intel in integer work in equal-core comparisons, but the floating point performance will still lag behind Intel.

Re:Will it be compatible with AM3?

[WiglyWorm]

It will be drop in compatable with AMD server boards. At home, it will be AM3+.

Re:AMD's stagnant?

[blair1q]

"AMD's lineup has been relatively stagnant while Intel continued to innovate with Nehalem and Sandy Bridge (due late this year) and the Bulldozer refresh is badly needed to keep in step."

Likely another Intel fanboy trying to spread FUD about the company that he doesn't like and at the same time getting his username posted on the front page.

The facts in that quote were presented clearly. AMD is a generation behind on architecture, trying to get comparable performance by multiplying old cores, while Intel has been advancing architecture and multiplying cores at the same time. For about 4 years now, Intel has had 2-4 chips performing at levels above anything AMD could produce.

It remains to be seen if Bulldozer will put AMD anywhere near at-par on a performance/core basis, but it's not 2002 any more, and AMD has no hope of a performance lead.

Re:AMD's stagnant?

[ArcherB]

Intel's hexacore offering features hyperthreading technology, which allows each core to execute two threads simultaneously. This means that Intel's hexacore chips actually have twelve logical cores, while the AMD hexacore chips only have six logical cores.

I think you may be misunderstanding what hyperthreading is. A processor (or core) can only execute one instruction at a time, hyperthreading or not. All hyperthreading does is allow for two sets of instructions to be queued up, so if one thread (or queue) gets hung up for whatever reason, like waiting over a cache miss, the other instructional thread can proceed, rather than patiently waiting in line.

Think of it as one of those tumbling thingies you have to pass through to get into Six Flags or the subway. It's like that, but hyperthreading has two lines instead of one. If one moron has to stop to find his ticket at the front of the line, the other line may move until he finds it.

Your number of physical cores comparison is meaningless...

Um... no. I believe your "virtual" core comparison is meaningless. I'll take a quad core anything over a dual core hyperthreaded-anything-else any day, thank you. Virtual cores don't mean shit until a thread stalls.

and actual performance benchmarks show that the Core i7 980X is more than twice as fast as the AMD Phenom II X6 1055T. [1]

From the site you linked:

Intel Core i7 980X @ 3.33GHz: Score of 10,325 at $989.99*
AMD Phenom II X6 1055T: Score of 5,146 at $194.99*

Hmmmm... Twice the performance at over 5x the cost. Strange, I don't know why you chose that AMD chip. It's odd that you would choose the fastest Intel chip and a middle of the road AMD Chip. Why not this one?
AMD Phenom II X6 1090T: Score of 6,057 at $289.99*.

Oh, I know. Thenyou wouldn't be able to use the 2x faster line. I get it now.

Here, take a look at THIS chart and pay attention to the price/performace graph. You'll see that your chip performs about 2.5x less than the AMD Phenom II X5 965 when price is a consideration. Oh, and for nearly everyone that is not living off their mommy's credit cards, price is a consideration.