ASUS V8420/td Graphic card cann't run at 2x tranfer rate Why

Actually I have tried to said that my ASUS V8420/TD Graphics card can only run at 2x transfer rate, but cann't reach 4x level, the BOIS had update to be the latest one. and Graphic card drivers has also been updated.
In the BIOS setting section I had set the AGP Mode as '4x' and AGP Aperture Size as '128MB' then left AGP Comp. Driving as 'Auto'. But the Graphics card cann't reach to be 4x transfer rate. I don't not why.
Thanks anyway for the response.

The following configuing information tested by PowerStrip Software, it might be identified the problem:
Diagnostic report - generated on 2005-4-20
------------------------------------------------------------------------------
PowerStrip build - 438
Windows build - v.5.0.2195.2.Service Pack 4
DirectX build - v.5.3.0000000.900 built by: DIRECTX
OpenGL renderer - (n/a)

System board
------------------------------------------------------------------------------
CPU speed - 997 MHz
Type - VIA
AGP aperture - 128 MB
AGP transfer mechanism - DMA
AGP non-local memory - 124.4 MB
AGP driving value - ECh (N-ctrl=14, P-ctrl=12)
AGP revision - 2.00
AGP transfer rates supported - 1x, 2x
Current AGP transfer rate - 2x
Sideband addressing - Enabled
Fast write protocol - (n/a)
AGP texturing - Enabled

Graphics card #1
------------------------------------------------------------------------------
Identity - AsusTek Display controller
Memory clock - 445.50 MHz
Engine clock - 249.75 MHz
IRQ - 16, shared
AGP revision - 2.00
AGP transfer rates supported - 1x, 2x
Current AGP transfer rate - 2x
Sideband addressing - Enabled
Display driver - nv4_disp.dll, v.6.14.10.7181
DirectX driver - nv4_disp.dll, v.6.14.10.7181
Attached monitor - ???2????

According to power strip your motherboard only supports 1x and 2x NOT 4x. Have you looked at your motherboard specification???
Just realised your motherboard has the new PCI Express technology - which I know very little about - from memory a PCI express 1x can be equivalent to say a AGP 8x. But read these links - they may explain
http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=RNWE,RNWE:2004-28,RNWE:en&q=PCI+express
Regards,
Peter

Okay, I just reviewed your motherboard user manual online in pdf format from the Giga-byte website. You DO NOT have PCI-E technology onboard that mobo. The board and card are both 4X compatible. There's likely something in your bios holding the AGP transfer rate at 2X. Many bios' have a feature to manually tune the AGP slot speed. I obvioudly can't view your bios, but it's likely in the chipset config. Don't confuse it with your AGP aperature size, that's not it, the choices will be 2X or 4X for your board. I'll trace the thread via e-mail, let me know how you make out. James.

For some reason was looking at the "Asus A8n-SLi" mobo which has PCI express.
Regards,
Peter

I figured you'd browsed to another mobo by mistake.

Thanks for your help, as your said that the AGP Mode has been set as 4x transfer rate in Chipest Config section at first time. In fact I have tried update the board drive which driver is described as following:
__________________________________________________
VIA Service Pack (VIA 4 In 1)

About VIA 4 In 1:
VIA 4 In 1 driver includes four system drivers to improve the performance and
maintain the stability of system using VIA chipset. These four drivers are:
VIA Registry (INF) Driver, VIA AGP VxD driver, VIA ATAPI Vendor Support Driver
and VIA PCI IRQ Miniport Driver. For Windows NT users, VIA IDE Bus Mastering
driver is only driver to be installed to your system

VIA Registry (INF) Driver is to be installed under Windows. The driver will
enable VIA Power Management Controller.

*VIA AGP VxD Driver is to be installed if you are using and AGP VGA card.
*VIAGART.VXD will provide service routines to your VGA driver and interface
directly to hardware, providing fast graphical access.

VIA ATAPI Vendor Support Driver is used to fixed the compatibility issue for
IDE devices.

VIA PCI IRQ Miniport Driver is to be installed under Windows 98 only, it will
fixed PCI IRQ routing sequence.
_____________________________________________________

There are two components may effect to AGP controller.
but even I undate system by this VIA Service Pack. Win2k system alarm me one program is non reaction when windows try restart system, so the Graphics card still run at 2x.
No idea ...

A week ago I have also email to Gigabye Technic support Department, might get some sounds back to me.

Thanks anyway.