CPU/ Memory OC Question!

[FearoftheNight]

Ok...I give. Whats this business of running fsb and mem synchronously? Plz...I know its running it same same speeds but what exactly does that mean? I know they says you run the 333 mhz fsb of bartons w/ pc2700 at 333 mhz. Since the true fsb is 166 x 2 do you set the fsb speed to 166 in bios? In that case w/ my Athlon Xp 2100+ w/ 266 mhz fsb. Do I need 266 mhz pc2100 ddr? But what if I have pc3000 ddr? Can I adjust fsb speeds in bios to make it synchronous? Someone clear this up for me please.

 

[petrek]

If what I understand is correct, you would start by adjusting the fsb in your bios to 183 (half of the pc3000ands ddr speed). From what I gather the major problem in ocing is the motherboard and thusly the bios revision contained therewith. Obviously a high end cpu (tbred B or the like) and high end Ram (preferably at this stage to be pc3200 or above) are also very important, but (again if my understanding is correct) if the motherboard doesn't support manual adjustments to the fsb, the parts, high end or not, don't really matter.

So as long as you have a decent mobo you should have no problem just going about changing the fsb to a sychronious 183, and then slowly increasing it until the comp becomes unstable, then lowering it back down a few notches (unless you want to up the voltage). At this point you would use prime95 to test the stability of the machine. If you can run it for a few days your good to go, if not, I suggest you lower the sychronious fsb until your able to run prime95 stable for a few days.

Another thing to watch for is the pci bus which you want to keep in the 33-36mhz range to prevent hdd failure. The newer boards (8RDA+, etc) allow you to lock the agp/pci speeds while fiddling with the fsb.

On the board I currently have (for about another week), all I did was go into the bios and find where the fsb options were hiding (most likely under a "default" setting) and up it, restart, up it, restart...until the comp couldn't load windows all the way. Then I set it back down two notches and worked on the Ram (cas latency, and speed: normal, fast, ultra, etc). The ram was crucial so it was able to take the most agressive settings, but the last few settings didn't really affect the sisoft scores (all of which I wrote down for ease of comparison), so I left it at cas 2 ultra 2/4.

Thus after adjusting the fsb, and the memory timings (which always reset after I changed the fsb :| ) I started prime95 and let er run a few days. No errors .

My fsb options looked something like:

1) cpu 133mhz ram 133mhz pci 33mhz
2) cpu 137mhz ram 137mhz pci 34mhz
3) cpu 140mhz ram 140mhz pci 35mhz
4) cpu 143mhz ram 143mhz pci 36mhz
5) cpu 147mhz ram 147mhz pci 37mhz

hope that helps
D