KT400A In Detail
The following table has been taken from VIA's website and lists the current chipsets and their features. Besides the improved memory interface, the KT400A can make use of VIA's new southbridge VT8237 with an integrated four-port Serial ATA controller. However, the test sample we received from Gigabyte comes with the old one (VT8235).
| Header Cell - Column 0 | KT400A | KT400 | KT333 | KT266A |
|---|---|---|---|---|
| North Bridge | VT8733A | VT8377 | VT8367 | VT8366A |
| Processor Support | AMD Athlon XPAMD Duron | AMD Athlon XPAMD Duron | AMD Athlon XPAMD Duron | AMD Athlon XPAMD Duron |
| Front Side Bus | 200/266/333 MHz | 200/266/333 MHz | 200/266/333 MHz | 200/266 MHz |
| Memory Bus | 200/266/333 MHz | 200/266/333 MHz | 200/266/333 MHz | 200/266 MHz |
| AGP Support | AGP 8X | AGP 8X | AGP 4X | AGP 4X |
| Memory Type | DDR200/266/333/400 SDRAM | DDR200/266/333 SDRAM | DDR200/266/333 SDRAM | DDR200/266 SDRAM |
| Max. Memory | 4.0 GB | 4.0 GB | 4.0 GB | 4.0 GB |
| South Bridge | VT8235, VT8235CE, VT8237 | VT8235 | VT8233, VT8233C, VT8233A or VT8235 | VT8233, VT8233C or VT8233A |
| North/South Bridge Link | VIA V-Link@ 533 MB/s | VIA V-Link@ 533 MB/s | VIA V-Link@ 266 MB/s | VIA V-Link@ 266 MB/s |
| Integrated Audio | AC'97 6 Channel | AC'97 6 Channel | AC'97 6 Channel | AC'97 6 Channel |
| Integrated Modem | MC'97 | MC'97 | MC'97 | MC'97 |
| Integrated Network Controller | VIA 10/100 Ethernet MAC | VIA 10/100 Ethernet MAC | 3Com (VT8233C) or VIA (VT8233 or 8233A) 10/100 Ethernet MAC | 3Com (VT8233C) or VIA (VT8233 or 8233A) 10/100 Ethernet MAC |
| PCI Devices/ Slots | 6 PCI | 5 PCI | 5 PCI | 5 PCI |
| IDE | ATA 33/66/100/ 133 Serial ATA (VT8237), up to 4 devices | ATA 33/66/100/ 133 | ATA 33/66/100 ATA 133 with VT8233A South Bridge | ATA 33/66/100 ATA 133 with VT8233A South Bridge |
| USB | USB 2.0 8 Ports | USB 2.0 6 Ports, 3 Controllers | VT8233 series USB 1.1 6 Ports, 2 Controllers VT8235 USB 2.0 6 Ports, 3 Controllers | USB 1.1 6 Ports, 2 Controllers |
| Super I/O | LPC Super I/O | LPC Super I/O | LPC Super I/O | LPC Super I/O |
| IO APIC | Yes | Yes | Yes | Yes |
| Power Management | ACPI/APM/PCI/ PM | ACPI/APM/PCI/ PM | ACPI/APM/PCI/ PM | ACPI/APM/PCI/PM |
The improvements inside the memory controller are called FastStream 64 technology, which is a side blow to NVIDIA's dual-channel interface that runs at 128 Bits. It's quite obvious that pure bandwidth is not always the key to high performance, a fact with which Rambus DRAM always had to contend. An intelligent prefetch buffer array has been integrated into the memory controller in order to reduce latency. This is, most of you might still remember, the main reason why KT400 plus DDR400 performed comparatively poorly in contrast to KT333/ KT400 teamed up with DDR333.