FSB and Processor Questions!

[davidkay]

I am about to build a PC for the first time. I was looking at an AMD 1GHz to build and want to buy a Abit Athlon Socket A motherbord (RAID one).

I have been told that i need to make sure that I buy a special type of 1GHz Processor and make sure its the 133MHz version and not 100MHz as my system will have 133MHz RAM.

I was looking at the Athlon Processors but there seems to be no mention of what FSB speed it runs at. The Intels however seem to have special type of Processors. There are two versions of the intel's a 100MHz FSB version and a 133MHz FSB version.

How comes the intel ones have different versions but the AMD's dont?

Please excuse my stupidness but I have not been researching recently in the PC field!

 

[Fardringle]

The 133Mhz version of the Athlon is a new development and is not yet available, although motherboards supporting this technology should be available before the end of the year. All Athlons and Durons currently in production use a 100Mhz FSB. You can use your PC133 memory with a computer running a 100Mhz FSB and just set the memory speed in the BIOS to FSB+PCI to have the memory run at 133Mhz.

 

[TheCorm]

Good choice with the Abit motherboard, I have a KT7 too, just the non-raid version, very good motherboard and the Softmenu III that allows you to clock your processor to a variety of speeds is excellent (be v careful when doing so of course though).

I have 100mhz SDRAM on mine, you can put wither 100 or 133 mhz memory, it supports both.

Both Athlon Thunderbirds and Durons have a 100mhz FSB that runs at DDR 200mhz (performence rated)

AMD are going to be releasing a Thunderbird with 133mhz FSB (or 266mhz DDR PR) but i'd go for the 1ghz Athlon, that will be a screaming fast system.

Corm

 

[WetSprocket]

David very good question. And good answers above I would just like to add something. The chipsets (motherboard chips) that run the Athlon CPU can run memory asynchronous(sp) with the cpu fsb. On the Athlon they do not have to run at the same speed. Even saying this I even doubt that you could find an Athlon(to buy) that was set for the 133mhz fsb right now.

 

[davidkay]

Thanks for such quick answers!

i am still unclear on a few things? Firstly by doing the 100MHz + PCI, is that overclocking it at all? or is that normal?

By the way, will my Motherboard detect that I have a 1GHz Athlon Processor and automatically set the values. If i have to do it myself, what do I put the multiplyer clock as? should I multiply it by 100MHz or 133MHz?

So would it be 10 x 100MHz or 7.5 x 133MHz?

Apart from the CPU settings is there any other settings i need to change? Please excuse me but i have never built a PC before!

Also, i will be ok having 133MHz RAM on a 100MHZ FSB Athlon?

Thanks so much for the help!

 

[Dravic]

david..

The abit board allows you to run the memory at a different speed then the front side bus. So you can run you ram at 133mhz(fsb+pci), while your FSB stays at 100mhz. You wont be able to run it at 7.5x133, the FSB on the athlon boards wont go that high. The FSB on the athlon motherboard is called the EV6 bus. Which means it can send data on both the up and down tick of the system clock, instead of just up or down. meaning.. A FSB speed of 100mhz runs effectively at 200mhz. So a 133mhz fsb would be 266mhz(just now coming out, and requires faster ddr sdram).

What you can do is set the core to run at 10x100, and run the memory at 133mhz. The 2 clocks dont have to be in synch, hence asynchronous.

For instance, I have my Duron 650@896(112x8). I have raised my FSB to 112(224 effective) from the 100mhz. One thing you have to remember is that the PCI runs at 1/3 FSB (112/3 = 37.3333 pci).

So my memmory is actually running at FSB+PCI or 112+37 or 149.

As for it auto-detecting the cpu speed, I'm sure it will, but you may want to do it manually for tweaking.

I could run mine at 9x100, but its much slower then the 8x112. 869 with at 224mhz FSB(effective) is fatser then 900 with a 200mhx FSB. But dont forget its increasing the speed of my memory doing this, since the pci bus runs a 1/3 the FSB no matter what. so I have 896 with a 224mhz FSB and memory ar 149 cas2..

I could also choose to run my memory at 112, by just setting it to the FSB(hstclk on the abit), instead of FSB+PCI

Try and run you FSB as high as you can. Memory throughput is by far ONE OF the biggest bottlenecks of today's PC

please ignore all typos and SP mistakes...

peace,

 

[itsmeeh]

hey dravic, what voltage are you running at? also, does the quality and the speed of the ram make a HUGE difference overclocking the fsb? How big would the differnce be if im just using pc100 generic ram? Text:Q

 

[TheWiseOwl]

Dravic (or other people in the know):

I have an Abit (KT7-RAID) with good memory (Mushkin PC133 Rev. 2 CAS2) with a Duron 600. I want to overclock to find the max I can push this setup. Am I thinking correctly in doing this one step at a time? I have in mind something like this:

1. First, push the memory up without touching anything else. Put it to turbo, CAS 2 and push up the speed of just the memory bus (not PCI yet).

2. After the memory is running as fast as it can go, then work on the CPU multiplier. Hopefully get it into the 8 to 9 range?? I guess I need to adjust the voltage in this step too.

3. Finally, push the PCI/AGP bus faster to see how fast I can put my GeForce2 MX and netword card.

So, is this the right approach or will step 1 effect something on steps 2 and 3? Or should I just change a bunch of stuff right away and then start pushing things up one by one?

Give me a direction please...

 

[kylebisme]

davidkay,
what everyone has said is totaly correct, however i would like to add that unless you are in a hury for the now computer it would be worth it to wait for the relase of all the new tecnology and either pick up the new stuff, suposably not much more expensive, or pick up the stuff that out now for even cheaper.



TheWiseOwl,
actualy you seem to have overlooked that your memory and your pci speeds are linked.
let me try to outline how these boards work for you:
the fsb runs at 100mhz
the fsb speed is divided by three to get the speed of the pci, 100/3 = 33.3
ram can be run at either-
fsb speed, 100mhz
or-
fsb speed plus your pci speed, 100 + 33.3 = 133.3

so like Dravic showed, when you overclock if you run your fsb at 112, then your pci would be 37 (112/3 = 37.3)
your memory would run at 149 (112 + 37.3 = 149.3)

as for wich to play with first, its realy up to you but this is how i would go about it with your setup.
memory should not be an problem so we'll worry about that later, but go ahead and turn on 4-way interlive and hostclock+picclock because those provide a masive prefromance boost and you always have those on if your ram suports it, and it does. you might as well turn on cas2 and turbo as they probably wont hold you back either. then up the multiplier untel you find the maximum stable speed of your cpu. set it back to default and now try the fsb untel you find the stable max for that. now that you now the max stable cpu and motherboard speed you can use any combonation of the fsb multiplier and ram bios settings, an test stablity. just rember that the more you up the multiplier the less you can up the fsb and vice-versa, so you probably won't get the max of both but you should find something sable in there somewhere.

 

[TheCorm]

davidkay,

Abit KT7 /KT7 Raid's Softmenu III is the best, you can adjust the settings of your CPU as much as you like (with special care I might add). I have a duron 750 mhz and if I had gone mental for a second, the board would have left me n it at 100mhz x 12 (1200mhz!!!) but that would be just silly.

When I went into the Bios the fiddle about with the settings, it was running my Duron at 600mhz, so I put it up to the CPU's default speed.

 

[TheWiseOwl]

Well, after your advice and more research, here is what I have come up with on my system. It started life as a week 29 locked Duron 600 at 1.5 volts. I'm running it on an Abit KT7-RAID motherboard with Mushkin PC133 Rev. 2 222 memory and a stock heatsink. It all seems to run fine with these settings:

Multiplier: 8.0
FSB/PCI Clock: 110/36
FSB Plus: +3
CPU voltage: 1.525
I/O voltage: 3.30
DRAM: HCLK+PCICLK
FAST CPU DECODE: FAST
DRAM Timing: TURBO
DRAM interleave: 4-way
SDRAM CYCLE Length: 2
Enhance Chip Performance: FAST

This gives a system running at 904mz (8x113) with memory at 149mz. The temps seem good too with the CPU at 42c (idle) and case at 30c. Not bad for a processor that cost about $80! So, a few questions:

The Mushkin ram ads says something about this memory being "222". I understand that one of the 2s is referring to running at CAS 2 (SDRAM Cycle Length on the Abit board). What do the other 2s mean and how does this translate into a BIOS setting on my Abit board?

The CPU voltage seems a little low for running at 900mz. During testing I had it up to 1.65 and then kept on dropping it until things got unstable. I was able to drop it all the way to 1.525, which is only .025 volts above the stock 1.5v setting for 600mz. Is this normal or am I just lucky?

What other settings should I play around with?

Thanks for the learning experience!