Funny the Single Core 254 beats the new Dual Core Intel in more tests than the Dual Core 280.
It's hard to tell whether that should be something to gloat about. In any case, you have to take into consideration the circumstances of those results. For example when the 254 beats everything in the first charts of SPECfp_base2000 and SPECint_base2000 thats because those were run in a single-threaded environment. In such a circumstance, obviously higher clocked speeds would be better which is why the 254 and the 3.6GHz single core Xeon can outperform their lower clocked dual core cousins. Similarly, when SPEC_CPU2000 is run in multithread mode then the dual cores should obviously see benefits.
The 254 also wins in the first 64-bit Linux because it's single-threaded. When 8 threads are used, Dempsey's advantage becomes more clear.
Let's analyze this Mr. TDP:
Those Xeon's use FB-DIMM DDR2 533 w/ 1066MHz FSB. The FSB don't matter, that is irrelevant w/ DDR2 533, but that 533 is the main point, that's 8,528 MB/s Dual Channel compared to 6.4GB/s on the Opteron 64 using DDR400. And FB-DIMM's But wait...FB-DIMM DDR2 can be scaled perfectly to use Quad Channel and Six- Channel which is 17,056 MB/s and 23,456MB/s, using FB-DIMM DDR2533. Intel plans to use Quad Channel, let's look at some numbers:
800MHz FSB: 6.4GB/s
1066MHz FSB: 8.5GB/s
1333MHz FSB: 10.4GB/s <=Approximation
Well...as we can see, even a 1333MHz FSB isn't quite to par w/ their Quad Channel ability and Six Channel, well, let's not go there. Let's see the Dual Independent Bus (DIB) plan for Intel:
Dual 1333MHz: 20.8GB/s
That is if they would implement Quad Channel and have 2 Channels per FSB...and that would give 2 seperate CPU's 10GB/s Bandwidth each, but each Dempsey is Dual Core and now each Core gets 5GB/s Bandwidth w/ each CPU having a 1333MHz FSB. But what about just Dual Channel? 8.5GB/s total, would they give each FSB a Single Channel? But think about the logistics, is it possible to seperate the RAM channels going to each FSB w/ 1 Memory Controller? Maybe, Maybe not, I don't know, but we'll find out. What if you can't? That means only 1 CPU can use their FSB at a time for Memory...but doesn't that create another bottleneck? Hmm...interesting...something to ponder...and what about DDR2-800 FB-DIMM's? :O! 1333MHz just aint enough...
Let's look at the Opteron 64 Socket F using FB-DIMM DDR2:
According to AMD, all A64's and O64's access memory @ CPU Frequency and have a direct link back @ RAM speed (hence Direct Connect Architecture), so let's see:
Opteron 64 FB-DIMM DDR2-533 Bandwidth:
Dual Channel: Full 8.5GB/s per CPU w/ independent DIMM's
Quad Channel: Full 17.56GB/s per CPU w/ independent DIMM's
Six Channel: Full 23.4GB/s per CPU w/ independent DIMM's
WoW, from that, it would seem that the Opteron 64 Socket F is better suited for the future, let's take a peek at Six-Channel FB-DIMM DDR2 but this time, let's throw in DDR2-800:
Six Channel:: Full 76,800MB/s per CPU w/ independent DIMM's
Holy smokes, w/ just 2 way systems, you're looking at over 150GB/s Memory Bandwidth for Socket F Opteron 64's...man that's pretty good. Let's look hypothetical here...for an extremely High-End Server w/ FB-DIMM's and 1207 pins, AMD could easily put on Multiple Memory Controllers per CPU since FB-DIMM's only require 69 pins from the 240 on DDR2 to actually go to the CPU..uh oh..can you say hundreds of GB/s....:O TB/s! o darn, things don't look good for Xeon's. But what about the Xeon's? I think you're the nice person to say "Intel plans Quad Independent Bus's", but how come Intel isn't touting that like a monkey waiting for a banana? What about the problems I noted w/ using the DIB alone? Hmm...anyway you look at it, the Opteron 64 CPU's are looking like the better option for the future, but since everybody is saying it, so will I: Only time will tell.
If you think something I said is wrong, make sure to reply and let me know, but let's keep it civilized, I enjoyed my 24 hour vacation but that doesn't mean I want another one.
~~Mad Mod Mike, pimpin' the world 1 rig at a time