i'm builiding a 1.2gig 266 t-bird system using the a7m266 mobo from asus. I intend on o/c'ing in the future. do i hae to open or close the l1 bridges, and if so how do i do that? no description makes kit very clear. and with the bridges modified can i run the processor at irts default level before i decide to o/c?
With the bridges modified you can run the processor at default speeds, but the A7M does not allow for multiplier adjustment manually. In order to change the multiplier, you'd have to modify the BP-FID and/or FID bridges as well, which may involve some bridge cutting, which is difficult. If you want to overclock in the future I suggest either getting a KT133A motherboard now, or, if you want DDR, waiting for the KT266 or wait and see if newer revisions of the A7M allow multiplier adjustment.
I've recently bought a new system similar to what you're going to build, namely 1.2Ghz T Bird 266 FSB on A7M266. My cpu is an AXHA and the level one bridges came connected i.e unlocked, however as one of the replies to your post said the A7M266 (my board is rev 1.04 ) does not currently provide any way of altering the clock multiplier. So your only easy overclocking option with this board is by increasing the FSB clock rate. This also increases the AGP bus and PCI bus and memory clock rate also. As standard the AGP runs at 66Mhz ( FSB / 2) and PCI runs at 33Mhz ( FSB / 4). The A7M266 does have quite good options for altering voltages which can be useful for overclocking. It allows the cpu core voltage to be changed, also 3.3V NB chipset and 2.5V DDR memory voltages to be altered