Overclock the AGP bus?

[Jeff7181]

Just wondering how overclocking the AGP bus effects performance. How much above the 66 Mhz default is safe, and what kind of performance increase would I see by going from say 66, to 75. Anyone have experience with this?

 

[DAPUNISHER]

IIRC certain Intel boards that Thugs and some of the other guys reviewed get over the hump when overclocking by increasing the AGP speed but mostly I've read it just causes instability with no real benefits to be found.

 

[frantadr]

Hi,
I run on ABIT BE6-II MoBo, PIII-1GE, AGP bus at 88.7 MHz, ATI Radeon 8500 video card. Rock stable.

 

[Jeff7181]

Originally posted by: DAPUNISHER
IIRC certain Intel boards that Thugs and some of the other guys reviewed get over the hump when overclocking by increasing the AGP speed but mostly I've read it just causes instability with no real benefits to be found.

I guess it would only help if the 266 MB/s (it is 266 right?) data transfer rate of the AGP bus is bottleneck... and since I'm running 4X AGP, that means it's effective able to transfer 1064 MB/s, correct? So maybe overclocking the AGP bus is kinda like going from 4X AGP to 8X AGP... only beneficial on the top of the line cards right now that are starting to reach the limit of a 4X AGP bus.

 

[Abzstrak]

cranked my agp on my a7n8x to 100MHz without a problem... I wonder if its really clocked at that though since it works so well... not too mention its running 8X AGP.... for reference the video card is a gainward ti4200 golden sample

 

[Corporate Thug]

does it help to change it at all when ocing?

 

[Wurrmm]

This is a really good question. I have always wondered if jacking the AGP clock would get more FPS in games.

 

[Tetsuo]

Originally posted by: Wurrmm
This is a really good question. I have always wondered if jacking the AGP clock would get more FPS in games.

I highly doubt it would, you would end up frying the card before getting the performance you want

 

[Jeff7181]

I decided to test it out... I had a saved game in SoF2 that I was using for some other testing purposes (linkage), was in an area with a couple light sources and some rain, so I thought hey, good place to test it.
If you want to know what hardware I'm running this on, chech my rigs.
Test is with 4X AF and nVidia's Quincunx AA (between 2X and 4X)

@ 66 Mhz
74-75 FPS... dropped to 68 FPS when I emptied the clip in my gun

@75 Mhz
75 FPS... dropped to 70 FPS when I emptied the clip

@85 Mhz
77 FPS... dropped to 71 FPS when I emptied the clip, then it locked up and rebooted by itself


... so... I guess the answer is, you can gain a few FPS if you sacrifice a ton of stability.

 

[pspada]

You are much more likely to get greater gaming performance combined with stability if you were to overclock the AGP video card (processor and/or memory), rather than the AGP bus itself.

 

[Jeff7181]

Originally posted by: pspada
You are much more likely to get greater gaming performance combined with stability if you were to overclock the AGP video card (processor and/or memory), rather than the AGP bus itself.

Of course... but aren't you the least bit curious if that would help at all? (before you saw my tests anyway)

 

[pspada]

I've never found the AGP bus to be very overclockable. I've tried it on numerous motherboard, with various types of AGP cards (mostly nvidia, tho), and never see anything 70 or above run with any reasonable stablility.

 

[MatthewF01]

I have a Chaintech 7NJS Nforce2 and a Leadtek Ti4200 128mb @ 320/590... and i have my AGP bus clocked at 77mhz...

i guess its stable...

 

[Lonyo]

Someone had a load of tests.

Found link: THUGSROOK did the tests: THUGS tests

 

[Desisuperman]

it makes a differnmce but only by a few fps, that ain't worth it at all escecially since it'sa not even a noticable change ! you'll just end up with a unstable card and yur increasing your chances of frying it.