AMD Overclocking for a complete NOOB

[Caviman2201]

Hey guys... I am currently running an Athlon XP 2400+ with the 266MHz FSB... I have a Via KT400-8235 chipset on a Biostar M7VIT Pro MoBo... I was looking around my CMOS today and I noticed there is a place where you can just dial up your FSB (i'm guessing it's the FSB) It's a typical Phoenix BIOS... It's right now at 133MHz which I assumed is normal because I'm running a 266MHz FSB... My question is, can I simply dial this # on up to up my FSB? How would I go about overclocking? I am a complete noob at overclocking but I know a fair amount about computers. I'm not trying to go hog-wild here with OC'ing... just get myself a little extra OOMPH... thanks guys :)

[Dragonprince]

Not a lot you can do with your current motherboard. I believe thats a KT400 chipset so you could unlock your processor and run it at the 166Mhz FSB setting to see a nice boost. You might be able to make 200Mhz FSB with a volt mod but I doubt the difference between 166 and 200 would be worth the effort.

I would run your ram as fast as possible (200Mhz DDR) if you have ram that will do 200 use it. Do not worry about keeping Ram and FSB in sync...thats a concern on nForce2 chipsets not VIA chipsets. Run the ram as fast as possible.

Be aware that changing the FSB setting requires some knowledge of what your doing. The VIA chipsets (unlike the nForce2 chipsets which have a PCI lock) are NOT PCI locked so you need to exercise some caution before making changes.

Most KT400 boards have a maximum 5/1 PCI divider, 6/1 if your lucky. What this means is when your FSB is at 166 your PCI clock is 1/5 as fast. 166 / 5 = 33Mhz. At your current 133 Mhz FSB the board falls back to a 4/1 divider to keep the PCI bus in spec.

33Mhz is the stock speed for all PCI buses. All PCI cards, AGP cards, and hard drive controllers on VIA chipsets run on this 33Mhz clock as a refrence for there internal timings. Remember this because it is important.

Moving your FSB speed to 180 would yield 180 / 5 = 36Mhz PCI bus which is the max that most PCI cards, AGP cards, and harddrives can handle, beyond this data corruption and damaged hardware is common. Proceed with caution and go slowly, at the first sign of trouble back off a notch and investigate if voltage increase to ram or cpu will help, if it does not help then you are at max for your board.

I would look around on Google for some articles on OCing KT333/KT400 motherboards and do some reading before you proceed.

Goodluck!

[c627627]

MHz speed = [FSB] x multiplier

You can increase either but the temperatures will go up and retail 2400+ heatsink is not meant for major overclocking.

[Caviman2201]

I know about the multiplier but I believe my CPU is in fact locked because I can't see it (Phoenix AwardBIOS calls it the CPU ratio) in CMOS... I have upped the FSB to 143 and the AGP bus is going 70 MHz and the PCI is running at 35 MHz. I'm not sure if i should go up another couple MHz in the FSB or not... right now i have a stick of 256MB DDR266, 256MB DDR333 and 512MB DDR400... I could pull out the stick of DDR266 and up the memory bus to 166... what do you think?

[c627627]

2400+ is [133] x 15 = 1995 MHz

[166] x 15 = 2490 MHz, your chip can't do that.

The best thing to do is take the PC2100 RAM stick out and hit
[166] x really low multiplier to see if you can do 166 FSB then find out ho much higher you can take the FSB, then up the multiplier.

Watch those temperatures!

P.S. multiplier locked doesn't mean "I can't see it"
It means you can select another multiplier but you can't post with any other multiplier than (in your case) 15.

[Caviman2201]

either way I can't change my multiplier without taking the heatsink off and modifying the chip, right?

[c627627]

No, the multipliers are changed in BIOS or on older mobos with jumpers on the motherboard.

The first thing you need to do is download your mobo manual or if you already have one, the first thing to do is read up.

The mobo manual will tell you how to change these things. It's different for different mobos, especially older ones.

[Dragonprince]

Originally posted by Caviman2201
I know about the multiplier but I believe my CPU is in fact locked because I can't see it (Phoenix AwardBIOS calls it the CPU ratio) in CMOS... I have upped the FSB to 143 and the AGP bus is going 70 MHz and the PCI is running at 35 MHz. I'm not sure if i should go up another couple MHz in the FSB or not... right now i have a stick of 256MB DDR266, 256MB DDR333 and 512MB DDR400... I could pull out the stick of DDR266 and up the memory bus to 166... what do you think?


I would pull everything but the 512m DDR400 ram and run your ram at the full speed. Again VIA chipsets thrive on fast ram more than a maximum CPU speed. 2145Mhz is not bad for an XP2400 and running the 512m ram at full speed will definetly give you the best performance. I would not exceed your current FSB setting though because at 70 Mhz your AGP is maxed out.

Try running AquaMark3 (if you have broadband to download it) at your stock speed with all your memory (including the DDR266 and DDR333) and then OC the FSB back to 143 with only the DDR400 memory...I think you'll see a decent increase you can be happy with.

If you really want to go higher than 2145Mhz I would recommend picking up an nForce2 board and another stick of that DDR400 ram for some dual channel love ;)

[Susquehannock]

Originally posted by Caviman2201
Hey guys... I am currently running an Athlon XP 2400+ with the 266MHz FSB... >>>>

Are you sure you don't mean "133 mhz"? If you are truely
at 266fsb your RAM will be running at 532mhz.
The 266 is likely your BUS speed. Remember, we have
DDR RAM so the FSB speed is doubled.

[Dragonprince]

Originally posted by Susquehannock


Are you sure you don't mean "133 mhz"? If you are truely
at 266fsb your RAM will be running at 532mhz.
The 266 is likely your BUS speed. Remember, we have
DDR RAM so the FSB speed is doubled.

The Alpha EV6 bus on the Athlon platform works at DDR just like the P4 is "quad pumped" so lets not confuse the noob ;) He's right saying its at 266....

[Caviman2201]

I am not a complete noob to computers... just to overclocking... I'm well aware that the Athlons DDR doubles the actual clock rate of 133MHz to get an effective DDR clock rate of 266MHz... I know a great deal about computers... just not much about overclocking...

the other thing (about the multipliers) is that I have searched through my rather skimpy motherboard manual and they mention nothing about how to change the multiplier... I always thought that Thoroughbred processors were "locked" and you had to do one of the unlocking procedures to access the multipliers...

also... Dragon... you really think that 512MB of DDR400 RAM is going to give me better speed than 1GB of DDR266? Even though my FSB is only running at 143MHz (DDR286)?