AGP Driving Force?

[Zerotech]

Hello again everybody!

I just upgraded recently from a socket A, nForce2-based motherboard to a dual-core system with a Via K8T800 chipset. I transferred my GeForce 7800 GS video card over to the new system and, I swear, it worked better in the five-year-old system!

A new thing in the dual-core board is the "AGP driving force" setting in the BIOS.
With it set to 'Auto', the setting defaults to 'DA' and performance sucks. If I change it to 'Manual' and adjust the setting to 'EA', performance improves greatly. But the performance improvement disappears after a reboot.

Does anyone have some experience with this setting? It would sure help to know the proper setting to get the most out of my videocard.

As a back-up plan, I'm bidding on an nForce3-based motherboard on eBay.

Thanks in advance for any help that can be provided.

[Platypus]

Hmm... is there any change to performance if you change the setting to manual, but leave the value as it is? From what little I understand of the significance of AGP Drive Strength, it's main use is for overclocking, like increasing voltage to memory & CPU core, except it sets the voltage swing on the AGP bus. But often mentioned seems to be that other AGP performance options may not be available until Drive Strength is set to manual.

So my first guess is that your previous board defaulted to agressive AGP performance settings, or let you modify them easily, the current board defaults to conservative "safe" settings unless Drive Strength is in Manual mode.

That doesn't explain why it reverts on re-boot, but some BIOS are smart (or out-smart themselves?) and refuse to hold a setting that is seen as incompatible with the hardware. That's why I wonder what happens if you select manual mode but don't change the setting. Will that hold across a re-boot?

[Ferrit]

It could also be a glitch in the bios on the board. Possibly a bios update will address such an issue. You will need to go to the manufacturers site and read what newer bios updates address if anything

[Zerotech]

Thanks for replying, guys. Sorry for the slow turn-around.

OK, some details:
the motherboard is an ECS KV2 lite (I know, but all in all , I haven't had any real trouble with ECS boards)

the CPU is an Athlon64 X2 4200+

the videocard is an eVGA 7800 GS CO Edition (256MB)

The BIOS was updated to the latest version (1/29/2007) before I loaded Windows (a few reviews I read highly recommended it).

The OS is WinXP Pro SP2 (still don't trust Vista).

The video drivers are nVidia's latest (v163.71)

With AGP driving force set to 'Auto' or 'Manual' with the 'DA' value, performance is low with missing or corrupted textures. In the 'Details' window of 3DMark03 or '05, fastwrites and sideband addressing show as "supported (disabled)".

Manually setting the value to 'EA' improves performance greatly (textures no longer disappear, corrupt or tear). Sideband addressing and fastwrites show as "enabled" after a cold boot, but are disabled again after a reboot.

I have been hesitant to set the value to 'FA' for fear of leaving myself with "FA" (a small chuckle for our British members). So I'm holding at 'EA' until I get more information.

I received a reply e-mail from ECS technical support, but it was pretty useless (imagine! ). Still waiting for a reply from eVGA tech support.

Hopefully I've provided a little better information here than in the first post.
Thanks for your patience.