Comments on: Intel server revamp to follow AMD

The chipmaker plans to launch an internal computer communications system that mirrors a technology central to AMD's gains.

[Dachi]

Poor Cray

I think Jan Silverman's comments at the end of the article are a bit unwarrnted. AMD has done their fair share of following too.

Cray has a contract with AMD so they are not exactly a neutral source, and I know people tend to associate Cray with "supercomputers" but these days they hold only a 3.2% share (and falling) on the top500.org list. AMD systems make up 3/4's of their 3.2%.

Looking here: http://top500.org/stats/27 under "proc family" you can see that Intel now powers > 60% of the systems on the top500. list.

Cray has every reason to skew Intels image.

[fred dunn]

AMD used to follow then Intel had to follow...

AMD for the very reasons Silverman stated. Intel had a 32/64bit project but scrapped it because they "knew" we all wanted Itanic instead of x86.
It turned out that they just flat bet on the wrong horse.
They "knew" we all wanted RAMBUS RDIMMs so that's all they supported in their first P4 chipsets, OOPs they bet on the wrong horse again!
Even after AMD gained market share in the server area for multi-processor systems becuase they had Hypertransport, they knew that we want higher latency and wait states implementing their HUB architecture, OOPs it looks like they are finally admitting that throwing cache at the problem is not the solution.
Also the Intel spokesperson indicated that AMD didn't put more cache on their chips because they weren't at the same geometry yet, That's bunk it's because they didn't need as much cache because they weren't in as many wait states waiting for the bus arbiter to allow it to talk.

I applaud Intel for finally figuring out that their FSB HUB architecture was inferior in multi-processor systems, but just as was the case for the preceeding scenarios they are always late to the party.
This wasn't always the case but they got the "Not Invented Here" syndrome and if if wasn't then we (the consuming IT public) didn't need it. This is whay AMD gained share and Intel lost share.
Also Intel has sold more processors than AMD in all cases but the issue was not that, it was that AMD was gaining ground and Intel was not only starting to lose sales to AMD but the informed IT public knew it was a superior technology.
I will say that Intel has come a long way for their single processor systems with the Core architecture, good for them.

But throwing 16MB of cache at a server processor is admission in itself that their multi-processor architecture is nothing but a big bottleneck. What a waste of 65nM technology and die space. For the space they are putting that cache on they could probably put another two cores, L1 cache and arbitration logic.

[Hardrada]

big cache is still good

locality of reference is a good thing, but more difficult when the individual references consume more of the cache. To go to a 64-bit architecture with larger binaries and maintain similar levels of locality, the cache has to grow at the same rate as the binaries. Optimizations such as instruction bundling increase fetch sizes too, increasing the need for larger cache to maintain locality.

Additional hardware, cores, etc. is a brute force mechanism for improving perf that typically comes with increased production cost, lower yields (due to complexity) and higher power consumption.

Frankly, I can't believe AMD has limped along with tiny little caches as long as they have. Once they transition their register file completely, they'll have to make this change. When they do, their codegen will be simpler and their perf will improve.