OC'ing a T-Bird 1.2 on a Abit KT7A-RAID can someone please explain?



New Member
i was reading a post on oc'ing a Tb 1.2 with the new abit kt7a and i have a few questons.

First off i guess i need the basics, like what is the multiplyer clock? and how does the multiplyerclock*the FSB speed affect the speed of the CPU?

second, how does the speed of the memory bus work with the FSB? does the speed of the memory affect the FSB or CPU at all? is having pc150 (kingmax) gona give you a faster system than pc133(mushkin rev2) memeory?

third, the post i was reading said you could buy a TB 1.2 that came "factory unlocked", is this a special chip? or do all TB 1.2's come factory unlocked?

i read another post that said this:
"As of right now I don't see spending $350 for a 1.2Ghz 266, $400 for 256MB of DDR 2100, and $200 for the board.($950 total) When you could get a 1.3Ghz guaranteed overclocked for about $250 and a KT133a for about $160 and run that chip at 133fsb. (Total $410 assuming you already have ram, $530 if you don't)"

does anyone know what chip would be guarenteed oc'd to 1.3? (1g, 1.1g. or 1.2g tb?) and also does anyone know of reputable sites one could find these deals?

Im new a OC'ing, so i apolagize for the probobly trivial questions.

thanx for any help you can give me.

outside looking in

Bah. Erm... Eh? Bleh!
PC150, PC133, and PC100 ratings are just telling you what the maximum rated speed of the RAM is. Kind of like a speed rating of Z on a tire. Doesn't mean it has to go that fast, just that it can.

The speed your memory actually operates is dependent on what speed you set the FSB to. Buying memory rated for a higher speed just means you have a greater chance of overclocking (of course, you want to at least buy the minimum neccessary to run in your motherboard at default FSB). I should add that many motherboards let the memory run at 133MHz while the rest of the FSB operates at 100MHz. Any new mobo should, so you want to at least get PC133 memory. I should also point out that some PC133 memory is much better than others, in that it can be ran faster than it's rated speed, but you pay for the increased quality.

My 1.2 Tbird is 'factory unlocked', and I would guess they all or at least most of them are. If you get one that's not, no big deal, it's easy to unlock.

I can only run 1.3GHz under win2k and retain 100% stability, but other chips might vary. I would guess my chip in win98 would have no problem at 1.35-1.4 with very few crashes.

Now, the basics. The FSB (front side bus) of the motherboard is the frequency of data communication between processor, ram, I/O, chipset etc. For AMD systems, the chipset talks to the memory at 100 or 133 MHz. The CPU talks to the chipset at 200 or 266 MHz. However, the clock multiplier in the CPU uses the 100 or 133 speed, not the 200 or 266 (not really sure why). So a 1.2 GHz Tbird has a default multiplier of 12 for the current 200FSB CPU's (12 * 100 = 1200). The new 266FSB Tbirds will have a default multiplier of 9 (9 * 133 = 1200) for the same speed CPU.

Now for the overclocking. Notice that there are two ways to increase the CPU speed: (1) increase the clock multiplier (13 * 100 = 1300), or (2) increase the FSB (12 * 108 = 1300). These two methods can be used independently or in conjunction in AMD systems.

Raising the FSB generally gives more increase in total system performance, since the memory speed and I/O speeds are also increased with the FSB. However, you run into more problems with memory failing at high speeds, or video cards or other cards not agreeing with the overclocked bus. Those problems are fairly uncommon now, as long as your memory is of good enough quality.

Raising the clock multiplier is easier and less risky, since only the CPU itself is overclocked. The down side is that you don't get the reward of increased memory speed and bandwidth from FSB overclocking.

In previous AMD systems, the KT133 chipset prevented the FSB from reaching speeds much above 110 MHz. Most people used primarily the multiplier to increase the CPU speed. In the new KT133a boards (and possibly the DDR boards), the FSB can be raised to 133MHz+ (some people reaching 150-160MHz). This opens up an overclocking possibility previously unavailable to AMD customers.

BTW, FSB overclocking is the only option availble for Intel systems.

Hope that helps some.

Those who fear the facts will forever try to discredit the fact finders. - Daniel C. Dennett

Soul Apathy

New Member
just a side note...If you are using a raid 0 configuration & overclocking be careful! if you have a little system instability it can trash your entire OS because there is no redundancy in a Raid 0 configuration

Abit KT7-R 1 GHz (Tbird) @ 1.210 100x11.5 1.800v
105 MHz FSB
384 MB SD-133
2 30 GB ATA-100 (RAID 0)
60 GB ATA-100 @ 66 (IDE)
Voodoo 4 4500 AGP
TV/FM Card
Poineer 12x DVD
8x4x32x CD-RW
TB-Santa Cruz Dolby 5.1