What should I set the CPU clock multiplier and frequency to?

[catback]

Hi,

I have an ASUS A7V133 board (VIA KT133A Chipset, 200/266 MHz Front Side Bus) with an Athlon 1.2 GHz chip. I also have PC133 RAM totaling 384 megs, two 7200 rpm ATA100 drives and an AGP 4x video card.

The system speed settings can be set using the BIOS instead of using jumpers. However, I’m not sure what I should set the CPU clock multiplier and frequency settings to. The manual is pretty detailed with other areas but seems to provide no help with these two. All it emphasizes is that these two settings multiplied together should be equal to the CPU chip speed or 1.2 GHz in my case.

The clock multiplier options in the BIOS range from 5.0x up to 12.5x, in increments of 0.5x. The CPU frequency ranges from 90 MHz up to 166 MHz in increments of 1 MHz.

Can someone please explain what exactly these two settings control and what I should set them to for optimal performance given the hardware I have? Thanks.

[chemmajik]

9x133=1.2ghz, I had a good write up but IE6 crashed, since you didnt tell us what your cpu tempatures where or what brand of memory you have & what your cas settings are, what cpu heatsink you are using, what your goals where quiet fast or loud fast? You increase the 133 up until the system is unstable 9x150=1.35ghz. But there are PCI bus issues(corrupting the hd), its best to do a search for your motherboard with it reviewed.
http://www.vr-zone.com/reviews/a7v133/
http://firingsquad.gamers.com/hardware/a7v133/default.asp
http://www.hardwareluxx.com/reviews/a7v13301.htm
http://www.amdmb.com/article-display.php?ArticleID=59
http://active-hardware.com/english/reviews/mainboard/a7v133.htm
http://www.overclockersonline.com/index.php?page=articles&num=61

http://overclockers.cssftware.com/cpudb/index.cfm
Use the database for the AMD 1.2Ghz cpu at www.overclockers.com

[catback]

Hi,

Thanks for the helpful reply and all the links.

Is it more effective, performance wise, to increase the multiplier or the bus speed? I currently have the multiplier set to 12.0x and the bus speed to 100 MHz for a total of 1.2 GHz.

[catback]

Hi,

Had another question that came up after reading several online articles about this topic.

My original BIOS setup, as mentioned earlier, was a multiplier of 12.0 and a bus speed of 100 MHz giving a CPU speed of 1.2 GHz. If I change the multiplier to 9.0 and the bus to 133 MHz as you listed, is this considered overclocking? I still get the same 1.2 GHz total but the bus speed has been increased in the process.

[TopHatTheater]

Increasing the FSB is more effective. Better memory bandwidth that way. But your system may not support it due to lack of dividers. You're running a 1/3 divider right now as your CPU is a 200MHz (100/3 ~33MHz PCI) At 133MHz, your PCI will be running at 44MHz and I believe this is high enough that your PCI cards will cause your system to fail to post. If your BIOS has a 1/4 divider, you'll be fine at 133MHz. Also, to change your multiplier, you'll have to unlock your CPU by connecting the L1 bridges with a pencil.

And yes, in a loose sense, you're overclocking.

[theReal]

Maybe the Athlon 1.2GHz is factory unlocked (but if it is one of the older 100FSB Athlons, I don't think so).
My Thunderbird 1.4GHz (133FSB) is factory unlocked, which is pretty nice (no pencil tricks and stuff).

Of course you're overclocking if you raise the FSB. You're overclocking your RAM, AGP, PCI...
Usually people aim for high FSB speeds first, then they look at how much the CPU can take.

In my case, the T-Bird 1400's default values are 133x10.5 - I set it to 144x10.5 first (1512MHz), then it could take nothing more. In the next step I found out that a memory timing of 8-8-6-2-4-2-2 was faster and more stable than 8-8-5-2-4-2.5-2, so I could set the FSB to 145. After lowering the multiplier to 10, I could suddenly set the FSB to 150 with no problems - the CPU had been limiting the overclocking at around 1530MHz.
Maybe I could get the CPU higher with even more aggressive cooling, but I really don't want to (that thing is already producing 82 Watts of heat...)

btw. you should always run a heat-monitoring program like MBProbe or Motherboard Monitor and run the Prime95 Torture Test after setting the FSB and/or CPU frequency higher.

Also, read the amdmb.com overclocking forum http://www.amdmb.com/vb/forumdisplay.php?forumid=4

[SpEeDaMiGo]

in your case 133mhz fsb (frontside bus) should be rock stable since the kt133a is a 133mhz fsb chipset and as result offers proper pci clocking ... I got the same mainboard too
thus, start at 133mhz fsb as previously said and increase in small steps ...
my config (gf256 ddr, isdn card, nic, scsi card, sblive 5.1, athlon B 1000mhz (10x 100mhz rated)) is running stable at 1350mhz with fsb 150 and ram timing 2-2-2 ... never really tried going higher
thus, as you can see there is a lot of overclocking potential ... just make sure you got proper cooling

and regarding whether fsb 133mz is overclocking or not: if you've got an athlon b (rated 12x 100mhz) then yes .... you'll loose warranty :devil: :D
if you've got a C version (9x 133mhz) then no

hasta luego

[diji1]

Hi,

theReal : run the Prime95 Torture Test after setting the FSB and/or CPU frequency higher.

good advice - though i would suggest running the sisoft sandra burn-in test with all modes on at the same time as prime95. running sandra will hopefully reveal any case heating problems caused by hdd or ram usage. if you plan on using ur overclocked system for gaming might i also suggest running a graphics benchmark as well to stress ur video card for the same reason - should know if ur agp interface can handle the higher speeds/heat that way as well.

[theReal]

If you want your cpu to produce all the heat it can, use CPUBurn:

http://users.ev1.net/~redelm/cpub4gi.zip

I couldn't believe it at first, but this little program heats your CPU so much like no other software, not even games can do. If the temperatures are ok with this one, you're safe forever.