Via K8T800 Pro

We take a sneak preview at AMD's new processor and the chipset that supports it.

Manufacturer: Via

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Verdict

Verdcit:
Both the processor and chipset look interesting, but we'll reserve judgment for final products.

Simon Crisp, Personal Computer World 28 Jul 2004

There seems to have been a ceasefire in the processor war of late, but this is all set to change in the next few months when the main adversaries, Intel and AMD, both bring out new Socket formats for a new line of processors. Just to stir things up even more, Intel will bring its new numbering system online and there are whispers that AMD may also have a new naming system.

While we have yet to see any of Intel's new 775-pin processors we have had the chance to look at an early example of AMD's new socket, which supports its 64bit processors. The new platform features a new 939-pin socket (PGA939), a 1GHz Hypertransport bus and, most importantly, dual channel unbuffered memory support.

The new processor will also only have 512KB of Level 2 cache instead of the 1MB of the current Socket-754 range, but its dual-channel 128bit memory controller should decrease the impact of this loss of cache, especially as it uses standard run-of-the-mill DDR400 memory. The Hypertransport bus is raised by 200MHz to 1GHz to make the most of the extra bandwidth provided by the new memory controller.

Eventually the new socket will replace both the current sockets - 754 and 940 - with the latter being the first to go. After the move to the new socket, the FX range of 64bit processors, which currently use the 940 socket, will continue to feature 1MB of L2 cache.

AMD has officially announced launch speeds for the new processors, with the Athlon 64s being the 3500+ (2.2GHz) and 3800+ (2.4GHz). The FX range is likely to expand to the FX-53 (2.4GHz) and FX-55 (2.6GHz).

We're also fortunate to be able to test a very early example of the new Via K8T800 Pro chipset, which supports the Socket 939. The new chipset will be available for all configurations of the Athlon 64; Socket 754, 940 as well as the 939.

Via's K8T800, the chipset of choice for AMD's Athlon 64 processors has also been updated to coincide with the new processors. First, the new Pro chipset supports upstream and downstream Hypertransport speeds of 1GHz. It's worth noting that the Athlon 64 doesn't have the traditional front-side bus (FSB). Instead, the processor talks to the northbridge via a Hypertransport link, which gives, in theory, at least a bandwidth of 8Gbytes/sec.

Secondly, and this is good news for overclockers, the AGP and PCI clocks now run independently of the Hypertransport link. Previous versions of the chipset had their overclocking potential stifled by the refusal of the AGP and PCI slots to work if the clock speed was altered. With the Pro, the AGP and PCI clocks can be set to 66MHz and 33MHz respectively, allowing both buses to remain stable while the FSB is ramped up.

The reference motherboard tested had the Via VT8237 southbridge but this will soon be joined by the new VT8251. The new southbridge will offer four integrated Sata (Serial ATA) ports, instead of the two previously, while the two ATA133 ports remain unchanged. There will be support for High Definition Audio (the new name for Intel's Azalia specification) offering support for eight-channel Dolby Pro-Logic IIx either natively or through Via's Envy 24PT chip. Also included is an interface for Via's Gigabit Ethernet chip and two PCI Express (PCX) channels.

Performance results from early examples of both the processor and chipset reveal that both show real promise. However, while the processor we had was rated at the correct speed, it's still a pre-production model and will be subject to architectural changes before it becomes available.

For this reason we haven't printed results. Needless to say, we'll get our hands on final versions as soon as they're available.

Contact:
Via www.via.com.tw
AMD www.amd.com

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