The First Hammer Board Hits the THG Lab – THG.RU

Waiting for AMD…

Even though we’re currently unable to show you a complete Hammer platform, we nevertheless bring you the very first motherboard with the VIA K8T400M chipset. However, we still hope to present the first tests of the ClawHammer before Christmas. Most of the motherboard manufacturers have samples with a clock speed of 1.6 GHz, labeled unofficially as “XP 3200+.”

A big issue at AMD is the thermal behavior of the processor, whose core is based on the 0.13-micron process. Compared to the Athlon XP with the Thoroughbred B core, the die surface has increased nearly 20% to 104 mmІ. This allows for more efficient CPU cooling as a result of the better ratio between the thermal power dissipation and the die surface. Also, new manufacturer guidelines will be coming from AMD: the cooler will not be attached to the CPU socket, as has been the case, and instead will be attached to a clip, which in turn is clamped to the motherboard with two screws. This will automatically mean a new source of revenue for established firms.

The Motherboard with the VIA K8T400M chipset and Socket 754 for the AMD ClawHammer.

The AMD Hammer with 1.6 GHz, which is unfortunately not available for testing.

Other changes have to do with the voltage of the mainboard, which is now connected to the 12 Volt channel of the ATX circuit via an ATX12 connector. Accordingly, it’s to be expected that the thermal power dissipation will increase to somewhere between 80 to 85 watt. Gone are the days when this was a rarity: Intel’s processors in the next two years should also have a thermal dissipation of 100 watt maximum, according to internal sources. Because of this, thermal design, and above all the even distribution of heat generation, will be playing an increasingly important role.

The socket of the future at AMD breaks a new record in the x86 world with 754 pins. The Intel Xeon is based on 603 pins.

VIA’s Offering for the AMD Hammer

Overview of the structure of the VIA reference board, including the connections between the individual components.

Most likely, AMD will launch the ClawHammer for the desktop market at CeBIT 2003. In the beginning, there will be a platform with a chipset combination consisting of the AMD 8151 Northbridge and the Ali Southbridge. The technically outmoded Southbridge, the AMD 8111, only offers USB 1.1 support, which is why another chip was needed for the USB 2.0 functionality. In general, motherboard manufacturers are refraining from using a combination of the two AMD chips and turning instead to solutions from VIA, NVIDIA and ATI. At the moment, it’s not quite clear yet whether or not the Taiwanese manufacturer SiS will be sitting in the same boat.

The following differences are to be found between the individual chips: with VIA, communication between the Northbridge and Southbridge will occur through V-Link-533. By contrast, there’s the pure AMD solution, which is the combination of AMD Northbridge and Southbridge that uses Hypertransport protocol (533). Note: the two protocols are not compatible to one another. However the Hammer CPU exchanges data with the Northbridge via Hypertransport at 1600 MB/s. VIA offers a total of three different chipsets for the Socket 754 platform: the K8T400, K8T400M and K8M400, which are simpler models with integrated graphics.

The various voltage areas on the motherboard.

Motherboard layout for the first layer.

Motherboard layout for printing.

The division of the individual pins on the VIA Northbridge (underside).

The division of the individual pins on the VIA Southbridge (underside).

The dimensions of Socket 754.

VIA VT8188A: Details on Thermal Protection

This circuitry is used on the VIA reference board. The thermal protection is controlled by the Maxim chip.

The following images show the reference material for manufacturing the VIA VT8188A boards. The interesting part is how the thermal diode is controlled: an external chip of the type 6657 from Maxim (AD1032, or LM90/LM86) takes over the overload protection of the K8 CPU. According to Maxim, the chip can detect temperatures between 60 and 100 degrees Celsius, where the test frequency is 16 Hz (16 test per second). The results of the first tests will show whether or not the CPU has additional internal protection. In any case, the logic of the Maxim chip can be avoided with the circuit signal “THERMTRIP_CPU.” Just as with the Athlon XP, the motherboard is switched off through protection circuitry. The circuit diagram shows the fundamental structure.

Details on the Motherboard: Sockel 754 for the Hammer

A view of the Motherboard with Socket 754.

The Motherboard is the first board for the Socket 754 platform to arrive in the THG lab. It’s based on the VIA K8T400M chipset and is equipped with the VIA VT8235 Southbridge. Three memory slots can be fitted with DDR333 at the most. An interesting feature is the integrated vacuum tube amplifier for 5.1 surround sound. Here, three tubes (satellite, center and stereo channels) are responsible for processing the analog signal. The following images give you a basic idea of how motherboards for the AMD Hammer are built.

The Northbridge of the K8T400M chipset.

The “Tube” in the board name refers to the vacuum tube amplifier.

The table for the Front Side Bus. Settings ranging from 100 MHz to 200 MHz are possible.

Underside: the contacts for the three tubes.

Underside of the Motherboard.

Detailed photo of the underside of the CPU socket. The short distances to the Northbridge and to the memory are clearly noticeable. The holes and fasteners of the clamp for the CPU cooler can also be seen.

The three tubes of the Motherboard with 5.1 technology.

The Southbridge VIUA VT8235: Ultra-DMA/133 and USB 2.0 are integrated.

In the Planning Stages: Dual-Channel DDR333 from VIA

According to a few motherboard manufacturers, VIA is planning to offer a chipset for the AMD Hammer with Dual DDR333 support. To explain this: manufacturers have found out that an external memory interface with Dual-DDR could provide a solution for more performance than what AMD had internally predicted. Currently, it cannot be determined as to the extent that this information ultimately has to do with a future VIA chipset launch.

An Overview: The AMD Roadmap

Although it’s hard to admit for some vendors, AMD’s Clawhammer was originally planned for 2002, as this roadmap shows.

Roadmap from AMD with die sizes.

The latest picture on the launch of Hammer shows how the various model numbers and CPU cores are going to be targeted in the coming months. So, we expect to see Clawhammer debut at CeBIT in March, 2003. However this isn’t the newest roadmap from AMD.

Overview: VIA Roadmap 2003

Excerpt from the latest VIA roadmap.

An overview of VIA Southbridges for the Hammer.

Compatibility of the various Northbridges.

Comparison: All Chipsets for the AMD Hammer

The tables below give you an overview of the most important variations of the different chips for the Socket 754 platform.

Architecture of the AMD 8151 chipset.