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Premium Computing - Gigabyte K8NXP-SLI and 3D1 together

By: Cameron Johnson | Editorials in Motherboards | Posted: Mar 8, 2005 5:00 am
TweakTown Rating: 9.0%Manufacturer: Gigabyte

Features of the K8NXP-SLI



Before we take a look at the video card, we fist need to look at the platform you have to run it on, why is that? The 3D1 is such a design that the only motherboard that currently works with the card is Gigabyte's own K8NXP-SLI motherboard since due to its SLI capabilities, running the card in other chipset boards results in the system refusing to post.


Due to the design of the K8 architecture, the K8NXP-SLI doesn't follow a specific reference design, which allows the manufacturers to design their own boards. Gigabyte placed the CPU socket in the dead middle of the upper part of the board with the DRAM sockets to the right. Four sockets are included to give Dual Channel DDR-400 memory support. With regard to component layout, Gigabyte has done a reasonably good job. This board makes use of the new Intel ATX 2.3 power specifications with a 24 pin E-ATX power plug and a 4 pin 12v P4 power supply to provide the CPU and PCI Express connectors.


Expansion wise the board supports two PCI Express x16 slots, two PCI Express x1 slots and two PCI legacy slots. Between the PCI Express x16 slots is a SO-DIMM connector with a special selector card. The card can be inserted into the socket in one of two ways, in Normal mode the top PCI-E x16 slot operates with all 16 lanes dedicated to the top slot and PCI-E x16 slot number two operates at only a x1 rate. When the card is inserted into the SLI mode, both PCI Express x16 slots are given 8 lanes each, allowing the use of two PCI Express video cards. When this happens, the PCI Express slot between the two video card slots is disabled.



The nVidia nForce4 (or CK804 as it's known in its reference stage) is the first chipset from nVidia to support their latest SLI technology. SLI allows two identical video cards (same type, size memory and manufacturer) can be inserted into two PCI Express x16 slots and linked with a special SLI link board to allow the two video cards to communicate, this allows one of the video card to do half the work while the other picks up the second half of the work.


Along with this the NF4 integrates support for three PCI Express x1 slots, four Serial ATA port and two IDE ports with nVidia's AnyRAID. This is definitely a first as this allows you to have the IDE and SATA drives linked together in one big RAID array, VIA have been working on this but nVidia is the first to bring it to market. Another good feature is the integrated Gigabit Ethernet controller that is connected using a HyperTransport link to the chip. nVidia uses a single chipset solution unlike SiS, Ali or VIA which use a Northbridge and Southbridge. With the memory controller being part of the K8 CPU, using a two chip solution is simply a waste of time, money and engineering.



You would think four SATA ports these days would be enough, however, Gigabyte has other ideas on their mind. With the every increasing amount of data that users want to store, having over four drives in a PC is not uncommon. To this end a Silicon Image 3114 4 port SATA controller chip is added to allow four additional SATA HDD or optical drives, deepening what the user requires.



With an already impressive lineup of features, it's hard to keep coming up with additional features to entice the end user. With the release of the new IEEE1394b standard, Fireire-800 is now going to take over where Firewire left off. Firewire-800 supports a maximum throughput of 800mbps, twice the amount of regular Firewire. This makes downloading raw movie data from Firewire-800 DV cameras a much quicker affair; however, the biggest benefit will come to Firewire-800 external enclosures. With 800mbps or 60MB/s transfer rate possible, external Hard Drives will find themselves freed of the link bottleneck that is common to USB 2.0 and Firewire.



Gigabit Ethernet was once only the dream of server and hardcore PC geeks, now it is a full blown desktop PC standard. The K8NXP-SLI has two Gigabit controllers. The first is built into the nVidia NF4 chipset using the VITESSE PHY controller chip. This allows the HT based Gigabit Ethernet controller of the NF4 chipset to communicate with Gigabit networks. The second controller is the Marvell Yukon PCI-Express x1 based NIC. This chip has been used on many of the Intel I900 series chipset boards, due to its seamless integration to the PCI-E bus.



As mentioned earlier, the board has a SLI selector card that you have to manually set in order to gain the SLI functions of the chip. The card itself if very simple in design, in Normal mode, the card routes all the trace wires of the PCI Express interface to the first PCI Express x16 slot. When this is done, the second PCI Express x16 slot is rendered down to a PCI-Express x1 slot which you can use for various other PCI-E x1 devices that are starting to emerge like TV and HDTV tuner/capture cards and SATA RAID controllers.


When the card is set to SLI mode, the traces on the card route 8 of the PCI Express lanes from the first x16 slot to the second, allowing you to use a second PCI Express graphics card. If you remove the card and don't re-insert it, the first slot is reduced to PCI Express x8 speed and the second slot stays at PCI Express x1.


After you do this you need to install the SLI link board. This board has simply two connectors and a bridge PCB. This is what you use in order to allow the two video cards to communicate with each other. The SLI link bypasses the need for the cards to use the PCI Express bus to communicate but rather a 2GB/s full duplex (1GB/s in each direction) link to communicate to each other exactly what part of the scene each card is rendering. Without this link you could end up with out of sync frames, not a very pleasant prospect when trying to play Doom 3 with the top half either ahead of behind the bottom half of the screen. In order to use the 3D1, you must set the SLI card to Normal, as both GPU's run off the one PCI Express x16 slot - more on this later.



Gigabyte has been pushing its Dual Power System or DPS as they have it labeled ever since the Prescott based Pentium 4's have come to market. What DPS does is adds an additional 3 or 4 phases to the voltage regulation system (in this case its 4). What this means is that stability when overclocking should theoretically increase due to a much cleaner voltage supply. The K8NXP-SLI has 4 phases already on the board itself, combined with the DPS module you get a full 8 phases to the CPU. This card is inserted in to a special VRM or Voltage Retention Module slot at the top of the board. This is then held in place by a metal brace that straddles the PCB.



Wireless Networking is also one of the biggest growing Ethernet standards. For their premium based boards that don't have a built in wireless option, Gigabyte supply a PCI based 802.11g wireless LAN card.


Now we have finished looking at the board, let's have a look at the card and what it has to offer.


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