Intel Pentium Extreme Edition dual-core CPU

Taken at the most basic level, a dual-core processor works much like a dual-processor computer, except that it only has one processor socket. The big difference is that in a dual-Xeon workstation or server the two processors have to communicate with each other, as well as with the system memory, so there's inevitably a performance hit as the processors negotiate which data they will each work on.

In a Pentium 4 PC you already have two 'virtual' processors thanks to Hyper-Threading (HT), which mimics a second core by giving work to under-utilised execution units. That's fine if there are under-utilised execution units to work with - if not HT doesn't bring any benefit. HT won't ever deliver the same performance boost as adding a second, fully functional processing core will.

Intel will make its first stab at dual-core later this quarter, perhaps earlier than it would have liked. To pave the way for the launch, it recently began seeding pre-release dual-core test systems, and we got our hands on one.

Naturally, a new processor requires a new chipset, so the 955X steps in to supersede the 925X, while the 945P takes over from the 915P, but other than dual-core support it's steady as she goes with support for DDR 2 SDRAM and PCI Express. The Southbridge is ICH7R. Intel also decided that the new processor needed a new name.

Out goes 'Pentium 4'. In its place we get two flavours of dual-core processor for the desktop: 'Pentium Extreme Edition', which has twin cores each with Hyper-Threading, so one physical processor appears as four virtual processors. This will inevitably be the $999 part that looks good on paper but doesn't get bought. Hence the dual-core part called 'Pentium D' that doesn't have Hyper-Threading. It runs on the same 800MHz FSB and has the same cache but it appears as two processors. No doubt Pentium Extreme Edition (PEE) will move to a 1066MHz FSB, which will allow Intel to enable HT in Pentium D (PD) but for now it all looks like a bit of a marketing nightmare.

It's quite clear that Intel appreciates its predicament as it sent us a complete white box, rather than a regular press kit of processor and motherboard, along with a stack of documentation six inches thick. It insisted we should recognise that this is pre-production kit intended to give us a flavour for the PEE 840, rather than being a rock-solid retail-ready set-up.

From the outside, the PC looks quite conventional, and if you peer through the window in the side of the case you can't see anything out of the ordinary either. The motherboard is an Intel 955XBK with a 955X Northbridge and an ICH7R Southbridge, integrated Pro/1000 PM Ethernet, HD Audio and Sil3114A RAID controller. There's 1GB of dual-channel DDR 2 clocked at 667MHz (PC5300) memory running 5-5-5-15 timings, a 160GB Seagate 7200.7 hard drive, a Plextor PX-716A DVD writer, Sapphire Radeon X850 graphics card and an Enermax EPS 12V 550W power supply.