New to AMD, have some general questions

[sygyzy]

Hi,

I have never been an AMD fan but that changed quickly when AMD told me I won a motherboard and cpu. Anyways, I have plenty of questions since I guess I am forced to build a new system now to replace my primary (*grin*)

1. Where can I get a list of what the XP specs are. Like my Athlon XP 1800+ is really what speed? 1.x Ghz right?

2. Do all XP CPU's run at 133Mhz FSB and have different multipliers to achieve the different speeds? I am used to Intel which seem to alter between 100 and 133Mhz FSB so that's where my mindset is at.

3. Where do I get a list of default voltages, multipliers and FSB for each XP CPU?

4. How do you overclock them? I read somewhere that it's best just to leave the fsb intact (as to not disrupt the other components like PCI) and change the multiplier. Why would this approach be best? On my Intel overclocking, changing the FSB allows for more precise overclocking. It's alot more subtle when you move up 1 mhz versus a whole 1x multiplier, isn't it? Is this the standard way of doing it or are there competing schools of thought in the AMD crowd? If this is all wrong to begin with, please tell me, I probably read it wrong.

5. Do you need to increase voltage when o/c on XP cpus?

Thanks. I'll have motherboard questions in the appropriate forum. I appreciate any help you guys can give.

 

[Bobek]

Wow, you´re what I call lucky man.

1)
real clock if XP line is:
1500+ runs at 1.33GHz
1600+ @ 1.4GHz
1700+ @ 1.47Hz
1800+ @ 1.53GHz
1900+ @ 1.6GHz

some info will surely be in amd´s website, they´re playing this PR game carefully.
I´ve seen some formula somwhere like PR=clock*3/2 - 500

2) Yes, you´re right

3) All XP CPUs run at 133MHz DDR (266MHz effectively), so you can easily calculate the multiplier (10x to 12x, 0.5 increments I think). They also use the same core voltage

4) Overclocking is easy when you only set the FSB. If you want to change the multiplier, the situation is much more difficult - physical modifications of CPUs L1 bridges are required. The how-to guide is available at Tom´s hardware.
There are also some boards which support setting PCI clock divider (usually FSB/4, FSB/5, FSB/6) so you can try to set divider to 5 and run FSB at 166MHz (then PCI bus will stay at 33.3MHz and CPU wil try to reach ~1917MHz, thus being XP 2376+ ). Since AGP bus runs asynchronously, then only problem is how high frequency can your CPU handle.

5) Increasing voltage may help when overclocking, just when you try to overclock any other CPU.

 

[sygyzy]

You are what I call an informative man. That helped more than you know. Does anyone have anything else to add? I will have to bookmark this so I can refer to it.

Follow up question: If I don't feel like unlocking the multiplier, can I overclock via FSB only? Any cons to this?

 

[Egrimm]

Nope, there isn't any problems with oc'ing the fsb only. My Xp1600+ runs with a 160fsb and default multiplier quite well, that means it runs 1680Mhz (10.5x160). Up to 1,6Ghz I don't even need to increase the vcore.

 

[Wind]

Generally, FSB increment increase overall system performance as the entire system bus is O/C. The FSB increment normally being halt back by PCI components not being able to take the off spec PCI bus. But w/ the current set of XP mobo, reaching 150 FSB is not "hard".

 

[sygyzy]

<< Nope, there isn't any problems with oc'ing the fsb only. My Xp1600+ runs with a 160fsb and default multiplier quite well, that means it runs 1680Mhz (10.5x160). Up to 1,6Ghz I don't even need to increase the vcore. >>



Does that mean you have a.. 1680 * (3/2) - 500 = Athlon XP 2000+ ?

That is amazing that you can go from 1.6 to 2.0 (virtually!) I wonder how high I can get my Athlon XP 1800+

Also, if all the intel crowd just overclocks with FSB and tweaking the voltage, why is it such a big deal with the AMD crowd to go through all the trouble of unlocking the multiplier and o/c that way? It seems to me using FSB is sufficient?

 

[Boonesmi]

the advantage to multiplier overclock is that the rest of the system stays totally in spec (when you overclock the fsb that means your pci/agp buses are overclocked, which also includes hard drives) fsb overclock increases the whole system performance, but... it also can cause all kinds of system problems


multiplier overclock is nice if you just want a little "safe" boost, i run my 1ghz tbird at 1.33 ghz totally stable by just changing the multiplier from 7.5x to 10x...... essentially my system is running just like a stock 1.33 instead of 1.0

 

[Emo]

I think Egrimm's example is not the typical overclocking result. Look at the cpu database at overclockers.com and see that most XP 1600+ overclock in the 1530-1630Mhz range. Also, don't expect to overclock to a similar level higher clocked XPs, t.e. if an XP1600+ overclocks to 1600Mhz, an XP1800+ may not reach 1800Mhz, probably 1700-1730 max.

 

[sygyzy]

WOW! That fact hadn't dawned on me. Change the multiplier and you still have your entire system running in spec (at 133mhz fsb). Genius! So with that being the case, does it mean the only barrier to overclocking using the multiplier is heat? As opposed of course to chnaging the FSB, in which case we have 1) heat 2) memory o/c 3) pci buses o/c etc.

 

[sygyzy]

<< I think Egrimm's example is not the typical overclocking result. Look at the cpu database at overclockers.com and see that most XP 1600+ overclock in the 1530-1630Mhz range. Also, don't expect to overclock to a similar level higher clocked XPs, t.e. if an XP1600+ overclocks to 1600Mhz, an XP1800+ may not reach 1800Mhz, probably 1700-1730 max. >>



I just want to reach the equivalent of a XP 2000+. Which means I will only need to overclock to 1667 and I will be set.

 

[Egrimm]

I agree that my oc is a "special" case, I'm amazed that it will run at that speed and with air-cooling, imagine if I got a water-cooling system, this is one heck of a chip I've gotten.
The typical results of 1600+ is below 1600mhz, haven't heard about any other people getting it above in fact, so don't get expect to hit such speed. I just got lucky and got a very good chip.
To reach 1667 with your 1800+, you would only have to run 145mhz fsb (without unlocking it), that should be possible. My cpu ran 146fsb with a mediocre Molex Radial Fin with no problems.

 

[jcmkk]

Actually most people don't unlock their multipliers to overclock, they usually unlock them to underclock. If you underclock then you can push your fsb higher getting more performance.

 

[sygyzy]

How would underclocking your multiplier and overclocking your FSB help you? You are still running the FSB out of spec right?

 

[Doh!]

Look at it this way. Between the following setups, which one do you think will perform better?

1. 1.33ghz at 10x133mhz
2. 1.33ghz at 13x100mhz

In most cases, #1 will perform better than #2 due to a higher FSB. In this case, all spec stay the same since you can adjust the bus ratio to 1/4 versus 1/3 in the 100mhz setup. So basically if you have a 1.33ghz TB running at 100mhz, you just underclock the multiplier to 10 and overclock the FSB to 133mhz to obtain better results (assuming that your mb chipset and memory support such overclocking such as KT133A w/ a PC133 RAM). Even if the FSB was higher than 133mhz, causing the peripherals to run out of spec, the performance improvement will justify the added risk of instability at the hands of experienced overclockers (who can maintain the optimal balance between performance gain and solid stability).