AGP port OCing

[Serra]

I've spent a good amount of time looking for exactly why AGP port OCing is bad and I'm hoping someone here can tell me, every other OC-related site just says that "it's not recommended". Is it discouraged because most mobos don't OC the port stabily, or is it actually hazardous to your system in some way? Personally, I seem to be able to run it stable (only 1hr of stress testing so far) at 86.67/43.34 without a vmod and thought I'd ask if it is a bad thing before I tested further and/or vmodded.

Currently I'm running a BIOS-flashed and OC'd ASUS Radeon 9550 (466MHz core, 266MHz [512MHz DDR] memory) on a P4P800-E Deluxe board.

~ Serra

[STEvil]

overclocking AGP can lead to graphical corruption as well as data integrity loss. Some P4 boards and Dothan boards will exhibit slow desktop and 3d performance as AGP frequency rises beyond a certain point or if the AGP lock is not working correctly past a certain FSB frequency...

The PCI frequency is usually generated by the AGP frequency (hence it is 1/2 of agp) and as PCI rises it can cause data corruption and/or system stability problems depending on the system setup.

BUT.. increaseing AGP frequency has also been proven to stabilize overclocks when certain FSB frequencies are reached... on P4 and Dothan setups ;)

[Serra]

Between the two posts so far I'm of the understanding that increasing your AGP port speed (and hence PCI speed as well) isn't usually suggested because of the possible negative effects on the lifetime of your video card as a result of higher stress conditions. Am I right about that, or did I miss something?

My queries from that point would be:
1. What level of additional risk are we talking about here [high/low]?
2. Would a good long stress test on my video card (approximately 8 hours) identify any issues that would come about as a result of this increase frequency?
3. Are there any noticable gains at higher AGP speeds for such a cruddy (but highly OC'd) video card?

~ Serra

[STEvil]

cant say i've ever seen a card die as a direct result to running the AGP bus faster.. i'd say there is little or no risk there.

Stability issues due to agp frequency will show up as: slow windows operation, random lines on a portion of the screen you are scrolling or in games when you are playing. Sometimes the video drivers will fail to initialize or will fail while in use and you will be dropped from the game or you will suffer a black screen with no video signal.. stessing the system by gaming will only help to test if the driver is going to "fail"..

Sometimes you can gain some performance by running the AGP bus faster depending on the card and system or drivers etc, but its not usually a significant gain noticeable in games.

[Den Leiw]

had my agp bus running @ 70 mhz and my radeon aiw 9800 pro died

I dunno if that's the cause cuz the vendor where I bought my card said many of these cards made by sapphire die after a while

[Rix2357]

I thought that people don't overclock the AGP/PCI was simply because there are no gains to doing so. Instead, all you get from it is instability from running out of spec.

[craig588]

Nope, you do get real performance increases, they are in the half of a percent range, but they definatly and consistantly are there.

[blinky]

going from 66mhz to 75mhz gave me around 50-80 points in mark01

[reject]

my CL jumped from 324 to 334fps which got me about 300 points at 80mhz
but i only do it for benching and mostly for 3d2001