Intel Socket-370 Celeron 366

Instead of completely admitting defeat and crawling back to Socket-7, Intel produced an entirely new interface design for their new Plastic Pin Grid Array (PPGA) Celeron processors based on the P6 bus (the same bus protocol used in Slot-1 systems) and called it, Socket-370.

As the name suggests, Socket-370 is a 370-pin Zero Insertion Force (ZIF) socket that will bring back memories of bent pins, voltage tweaking, and other such enjoyments from the days of the Socket-7 motherboard as the chip itself is the same size as the good ol' Pentium MMX.

The PPGA Celeron was released in two different flavors, a 366MHz version running at 66MHz x 5.5, and a 400MHz version running at 66MHz x 6.0. This release complemented the release of two identical Slot-1 Celeron processors, also clocked at 366MHz and 400MHz, however they are Slot-1 processors and not Socket-370 chips.

To put an end to all rumors, Socket-370 is not an inferior interface to the Slot-1 interface in any way, you can pretty much consider Socket-370 to be a physical variant of Slot-1, as that is the only real difference. A 300MHz Celeron in a Socket-370 board will run just as fast as a 300MHz Celeron in a Slot-1 board.

Socket-370 motherboards will only support Socket-370 processors, meaning you can't purchase a Socket-370 motherboard with hopes of upgrading to a Pentium II processor eventually (without a full motherboard replacement that is). On the other hand, although Socket-370 CPUs can't physically fit into Slot-1 motherboards, many companies such as Microstar International and ABIT will be offering Socket-370 to Slot-1 adapters that will allow you to use a Socket-370 Celeron in a Slot-1 motherboard (LX, BX, or Apollo Pro boardsnot older FX based boards though).

Socket-370 motherboards will generally fall into two categories, 66 and 100MHz FSB boards. Boards that support the 66MHz FSB will bring back memories, since they will most likely also support the 68MHz turbo frequency of the 66MHz FSB, in addition to the 75/83MHz overclocked settings. Boards that do not support the 100MHz FSB will generally be weaker in terms of expansion as they will be designed to be the most cost-effective solutions possible.

Here is where you'll see the return of the short-lived Intel 440LX chipset. Since the Socket-370 Celerons don't require the 100MHz FSB, the LX chipset is the ideal platform for a low-cost Socket-370 Celeron system while retaining most of the benefits of the current Pentium II market. Although Intel recently announced the release of their 440ZX-66 chipset (a toned down version of the Intel BX, made specifically for socket-370 boards), the ZX chipset doesn't offer any improvements over the LX or BX chipsets that would justify its positioning in the market. It looks like Intel has too much out at one time, since the ZX isn't cheap enough to compare to the LX, and it isn't great enough to compare to the BX.

Those boards that do support the 100MHz FSB will be much like today's top Pentium II motherboards, you can expect most of them to ship with a 5/2/1 (PCI/ISA/AGP) expansion slot configuration, 3 DIMM slots, and most of them will feature the ability to manipulate the core voltage of the CPU.

You can also expect jumperless configuration utilities to pop up everywhere, ABIT doesn't seem to be the only unique one any more, as even the Microstar and Shuttle Socket-370 engineering samples AnandTech tested had fully functional jumperless CPU setups. The CPU AnandTech tested wouldn't boot at any core voltage setting greater than 2.05v (2.1v would not post), this could be an indication that the newer Celeron processors are much more picky about the voltages they are set at, or it could simply mean that AnandTech got stuck with a bad chip, once again, a more extensive study of the CPUs on the market must be made before any analysis can be concluded.

VIA's recently released Apollo Pro Pentium II chipset has also been adapted to the Socket-370 arena, and you can expect the Apollo Pro to make a commanding presence among the Socket-370 chipsets, as with the Slot-1 market, performance is rarely an issue as all the chipsets perform within a reasonable margin of one another.

Overclocking was a big issue with the Celeron A when it made its debut on the Slot-1 platform, and very similar to their "slotted" brothers, the Socket-370 Celeron processors are clock-locked but not frequency locked as once anticipated. A clock-locked processor is one that only recognizes a single clock multiplier, such as 5.5x, while a frequency-locked processor is one that only recognizes a single frequency range, such as 495 - 505MHz. As of now, there have been no frequency locked processors released on the market.

As far as AnandTech's tests have shown, the new Socket-370 Celeron processors are only clock locked, and not frequency locked, this may change in the future, however AnandTech's retail sample of the processor seemed to work fine when overclocked. Cooling the processor wasn't a problem either, while AnandTech did use the retail heatsink/fan combo for the tests, due to the size of the Socket-370, most Socket-7 fans will fit directly on top of the processor and latch on fairly securely.

The 366MHz PPGA part AnandTech tested made it up to 458MHz reliably (83.3MHz x 5.5), unfortunately the part did not hit 550MHz reliably enough to be considered an option. One thing must be taken into consideration, this is a single processor, and there are quite a few out there. Once Intel's manufacturing process matures, the Celeron 366 may even grow to be the replacement for our beloved 300A's running at 450MHz. From the reports of Celeron 366 users all over the world, the chances that the 550MHz Celeron will become the next big thing to hit the tweaking world are good, for you Slot-1 users out there, don't worry, the Celeron 366 and 400 are both supposedly availabe in slot-1 formats as well, so keep your eyes peeled (although preliminary reports suggest that overclocking the 400 is about as useful as overclocking the first Celeron 333's, it could work, but chances are, it won't to the degree you want it to).