The LambCutlet Disorganisation

The watchword for 2005 on the CPU arms-race between AMD and Intel will for once not be about MegaHertz (well, GigaHertz really) but about multicore CPUs bringing to the mass market what us dually PC users have been known for ages… 2 are better than 1! The guys at X-bit labs have the lowdown on these new beasties from AMD, Intel and VIA.

In AMD’s case, this new technology will come to market in the 2nd half of 2005 via it’s server/workstation line of processors branded as “Opteron”, currently codenamed “Egypt”, “Italy” and “Denmark” and will arrive as the 800, 200 and 100 series respectively. Then filtering down to the desktop market, “Toledo” will probbaly be first marketted under the “Althon 64 FX” brandname. The mobile market isn’t left out in the cold either, and that segment should see “Roma” and “Albany”. The infrastructure is pretty much in place as the chips will use HyperTransport for inter-chip communications plus they will use exisiting sockets, with only a BIOS update required so that motherboards can detect the new CPUs correctly.

Intel’s is a little more interesting as it’s current Pentium4, previously codenamed “Prescott” is one very hot potato with it’s specification stating it consumes a stonking 115W, whilst just a little bit hotter than 72°C when clocked as 3.8GHz, falling way short of the 5GHz Intel had hoped for that generation. It’s initial successor, “Tejas” would ultimately suffer the same issues of monsterous power consumption and how to keep the damn thing cool, so the new Intel roadmap for 2005 brings a curious dualcored item under the codename “Smithfield”. It turns out that this desktop CPU would be based on the exisiting NetBurst architecture, as used with all current Pentium4’s albeit with extraneous transistors removed to save power and have HyperThreading disabled.

However, this still means that the new “Smithfield” processors will still have a total power envelop of about 130W, about 65W per core and will be branded as x20, x30 and x40 for 2.8GHz, 3.0GHz and 3.2GHz models respectively. Clockspeed is unlikely to go much higher till Intel moves these from their initial 90nm process, to the finer 65nm one as lower voltages and smaller transistors usually mean lower power consumption. What is interesting though, is that “Smithfield” will support Intel’s “Vanderpool” technology, which is a virtualisation technology and allows a single CPU to run more than one operating system as any given time. Intel’s own demonstration showed such a media PC where one instance of the operating system was being configured with setting changes, driver updates and finally a reboot all whilst the other instance of the operating system carried on humming along showing some digital video. Admittedly, this probably won’t be officially announced till Microsoft release their next version of Windows, codenamed “Longhorn”.

The x86 server/workstation front, the Intel Xeon brand, is rather bland with more or less the same type of thing what is to come on desktop. “Dempsey” will be the vanilla Xeon, targetted for 2-way configurations whilst “Paxville” will be the Xeon MP and targetted for 4-way or more. Virtualisation technology will again be supported, but will be called “Silvervale” and these cores, unlike their “Smithfield” desktop counterparts, will support HyperThreading which means “Dempsey” and “Paxville” will be able to execute 4 threads per core. Other differences include the support for FB-DIMM which allows server class systems to be configured with vast amounts of RAM (excess of 8GiB) without the need for motherboards to have masses of copper traces and/or many conductor layers, reducing cost and improving performance. The new memory type will also make the processors agnostic to exactly what type of memory they are using and thusly allows new types of memory to be used without the need to design a new memory controller, which currently resides on the core logic on the motherboards themselves. Dual Independant Bus will also be new for these future Xeon’s and is a point-to-point interconnect topology between the chipset “North Bridge” and each of the physical processors. This innovation alone could bring significant improvements to Intel’s multi-processor systems, as the current implimentation is a single shared bus which isn’t able to provide the bandwidth required by data hungry CPUs, hence the need to strap large amounts of expensive L2, and sometimes L3 cache.

Though for technological marvels, Intel have left the best two till last. First up is “Montecito”, the first dualcored processors of the Itanium 2 family and has an absolutely stupendous 24MiB of L3 cache which takes the transitor count of the core to an amazing 1.72 billion transitors, all packed into a space of 580mm². Even for it’s huge die size and clocked at a swift 1.7GHz, it still only consumes around about 100W making it a little less power hungry than the first generation of Itanium 2’s, yet increase performance by 2 to 3 times depending on the workload by virtue of a modest increase in clockspeed and having 2 cores where each one is able to execute 2 threads via a HyperThreading like technology. It all works as Intel have already showcased a 4-way “Montecito” system able to process 16 simultaeous threads!

The next ace up Intel’s sleeve would be of the mighty little Pentium-M family, a respin of the trusty Pentium3 core designed specifically for the low power consumption needs of the mobile market, yet not completely cripple performance whilst doing so. For example, the current signle-cored “Dothan” consumes at peak, 27W at a clockspeed of 2GHz giving similar performance to a Pentium4 clocked up to 50% higher. In the mobile market, only VIA has similar power consumption figures yet doesn’t have the performance and though AMD has similar performance clock-for-clock, those cores consume 35W which is some 30% more which in the real world means hours less battery run-time… Not cool! The dualcored Pentium-M codenamed “Yonah” by the looks of it will be quite a multimedia monster as it’ll be sporting massively improved SSE2 and SSE3 instruction units and it’s dual cores will only have a peak power consumption of less than 40W. During most of the time, one core will be disabled taking power consumption to below 20W yet clockspeed will exceed 2GHz. As the guys at The Inquirer say:

Other improvements, especially to IDIV will only add to this, you can probably encode a DVD on a flight, and still have battery life left over to watch the movie because this all will only consume 31W. Yonah, you go Grrl! Sorry about the lack of decorum, but it will be that good.

Now if only Intel would make say a 6-cored “Yonah” and market that as the ultimate desktop/workstation/server CPU… :D However, I’m sure some variant of “Yonah” will probably be used in single processor configurations as per “Dothan” now, in the blade server market.

Last of this processor roadmap crystal-ball gazing for what’s due to be released is VIA. It’s forthcoming Esther certainly isn’t going to win the performance crown as even when clocked at 2GHz, it would only be about the same as a Celeron 1.2GHz. However, it’s trump card is that it’ll only consume a tiny 15W peak. It also supports SSE2 and SSE3 though more curiously appears to use Intel’s 800MHz Quad Pumped Bus, and theoretically could be “drop-in” compatible to the existing Pentium4 infrastructure. In any case, it certainly sounds like a good CPU for the embedded, low-cost blade or cluster market.

Roll on 2005! :D