Athlon XP-M 2500+ Overclocking

[Fricardo]

Hello, I am new to these forums and was looking for some help on building a new system. Currently, the best overclocking CPU seems to be the XP-M 2500+ and i was looking to build a system around it.

From what I understand, every 2500+ (mobile or desktop) has a Barton core. Bartons have a 512k L2 cache and 333 fsb, right?

The thing is, every online retailer I have visited lists the XP-M 2500+ as having a 266 fsb. I knew that the voltage was lowered to 1.45 on the mobile version to save on energy consumption, but I was under the impression that otherwise it ran the same. Did they also lower the stock fsb? Nothing else I have read has mentioned this discrepency in the parts and I was wondering if I was missing something.

Is it simply that the fsb is easily raised? I have seen reports of people running this processor at 400 fsb. Is a 133 fsb overclock really possible? Any help would be much appreciated. This is the first hardware forum I've ever joined, so I don't have much forum experience. Sorry if I did anything wrong. Thanks for the help guys.


Current rig:

MSI KT3 Ultra MB
Athlon T-Bird 1.33 Ghz @ 1.47 stock HSF
1 Gig Ram @266 (2x256 PC 2100, 1x512 PC2700)
GeForce 3 OCed: 20 Mhz core, 60 Mhz memory
160 GB and 80 GB (Western Digital Special Edition 8MB caches)
330 Watt Enermax PSU

 

[kyparrish]

welcome to the forums, enjoy your stay

The mobile bartons and the desktop bartons are fundamentally the same chip. The mobiles show a 266fsb because they have to work in a laptop environment (which usually is only a 133mhz x 2 fsb) To make up for the lower FSB speed, the mobiles run with a higher multiplier.

However, the desktop Barton 2500's run with a higher bus speed (166 x 2 = 333mhz effective), but a lower multiplier.

Now, here's where it could get confusing. The desktop Barton's and mobile Barton's are the EXACT same chips. The mobile's are given a "mobile" label because they are the cream of the crop of the Barton's, and since they are the "cream of the crop," they can run their default clock speeds at LOWER voltages than all of the other chips coming off of the assembly line. A mobile 2500 can run 2500 speeds at 1.45 volts, where "normal" Barton's run that speed at 1.65 volts.

Obviously, a chip that can run default speeds with less voltage is a better chip. In the overclocking world, this voltage "headroom" means that you should theoretically be able to overclock a mobile chip farther than a "regular" desktop Barton.

Also, these mobile Barton's come multiplier unlocked. So, you can drop the multiplier and increase the FSB speed to increase your performance. Most everyone around here that has a mobile Barton starts at around 11x200 (2200MHz, or Athlon XP 3200+ speeds) and just goes up from there

 

[Verdant]

The biggest advantage, beyond the lower voltage rating is the unlocked multiplier

many people have been getting the mobile 2400+-2600+ to 2.4Ghz no problem, i have seen some people claiming 2.8 on air cooling.
my new one (2600+) is currently running at 2.6GHz for a week now, folding 24/7

i am running it at 200x13, (which for ddr peeps is 400mhz)
this is with a NF7 Abit MOBO

 

[kyparrish]

that's a heck of an OC Verdant...what voltage are you using to get that high?

 

[Fricardo]

Hey, thanks guys.

It had been by suspicion that they just lowered the fsb in order to up the multiplier. I just wanted to make sure that was the case before I blew my cash on a chip with the wrong specs .

I had another question about it actually. As you can see from my current rig, I have a 512 MB stick of PC2700 that I would like to use, at least until I have the money the spring for some new PC3200. I was hoping to just be able to get a new MB and CPU for now and salvage the rest of my old system. Its Kingston Value RAM that's rated to run at CAS 2.5 @333 DDR. Right now it hits 2.0 whithout a problem @ 266 effective on my T-Bird system.

Do you think I could run the CPU at 166 for a while and still get good performance? I figure the RAM would overclock a bit beyond that speed anyways. Would this still provide a good overclock if I just kept the multiplier up a little higher?

Also, I was planning on getting these new components, tell me what you think .

Motherboard: ABIT NF7-S Revision 2.0 (nForce2 Ultra 400)
Power Supply: Antec True Power 430W
Heatsink: Thermalright SLK-947U (is it worth the money to upgrade to the SP-97?)

Fan: (Here I need some help) Vantec Tornado
A lot of people say that this fan makes quite a bit of noise. Noise is not my first consideration - performance is - but I would like to keep it as low as possible. Do you know if this fan or another good fan has speed scaling so that the RPMs won't be through the roof if I lower the Vcore a little bit?

Thanks again guys, I appreciate the help

 

[Fricardo]

I've just been looking over fan controllers at newegg.com

The Vantec Nexus Fan Controller Panel looks pretty good and seems like it would help control noise when the computer wasn't under full load. Are these things actually helpful?

 

[hytek369]

Originally posted by: kyparrish
that's a heck of an OC Verdant...what voltage are you using to get that high?

that is sweet

 

[hytek369]

Originally posted by: Fricardo
I've just been looking over fan controllers at newegg.com

The Vantec Nexus Fan Controller Panel looks pretty good and seems like it would help control noise when the computer wasn't under full load. Are these things actually helpful?

i use a brand called sunbeam that is pretty good. i think it handles more watts than vantec.

 

[JnPrather]

Fricardo,

Regarding your ram being able to do Cas2 no problem. Do yourself a favor and take out the stick and look at the chips. I also have a stick of Kingston ValuRAM PC2700 (Cas 2.5 rated) (1x512)... When I upgraded to my current Athlon XP 2500+ system, I took a look at my ram and realized that it has Winbond BH-6 memory in it... Check your stick out, you might have the same thing. FWIW, my "PC2700 Cas2.5" stick is able to run above 190FSB with 11-2-2-2 timings... at 2.7volts... It might be able to go higher at 2.9v but my motherboard is limiting me at that speed... So check out your stick of ram, you might be pleasantly surprised to see that you're going to have alot more overclocking headroom than you think...

More than likely, your best bet is going to be to overclock the FSB as much as your Ram can handle (keeping the 1:1 memory ratio), and then upping the multiplier on the CPU as much as you can... you may very well be able to push 200fsb or near that without having to upgrade your memory... If you want to get really fancy you'll want to mess with ram timings and see if maybe running at cas2.5 (and other looser timings) would allow you a higher FSB and therefore better overall performance... Good luck

John

 

[Fricardo]

I checked out the chips on my RAM like you recommended John. It surprised me to see that they are actually Kingston chips. I wasn't expecting Winbond like you got (you got really lucky there ) but I didn't even know that Kingston made chips. Its either thiers or they stamped their name over another manufacturer's because that's definitely what they all say.

Does anyone know anything about Kingston chips? The first line of numbers on each chip is " V598XX " if that helps.

Anyway, I think with a little overvolting and slower timings it probably could hit higher clocks, but there isn't really any way to tell until you do it, unfortunately.

 

[kyparrish]

Fricardo, I run 1 stick of 512mb PC-2700 (Crucial) @ 204 fsb with 6-3-3-2.5 timings, and still keep a 1:1 ratio between the cpu and the memory.

You might have similar results if you just use the 1 stick of your PC-2700. 512mb of Ram is still enough for now for most of us. I used to have 3 sticks, the 512mb PC-2700 and 2 256mb sticks of PC-2100, and found that being able to run a higher FSB w/o the slower Ram was more advantageous than running a gig of memory that would only do ~145mhz fsb.

Seeing as how you can adjust the multiplier on the mobile Bartons, you would have a good shot at running something like 12.5x185mhz (2312.5mhz) with that heatsink you are looking at.

 

[kyparrish]

also, if you pick up that NF7-S that you are also looking at, it has plenty of options to raise the voltage going to your Ram...

my PC-2700 needs 2.7v (instead of default 2.6v) to reach that 204mhz fsb

 

[Verdant]

Originally posted by: kyparrish
that's a heck of an OC Verdant...what voltage are you using to get that high?

pretty high!

1.825v which i thought was pretty high, but the temp is fine, even under 24/7 100% f@h load.

it was actually running windows fine at 13x211 (2.7) but my f@h WU's weren't completing

edit: the included hardware monitor only reports the voltage at 1.8v...
it reports the cpu to be running at 50 C, and the case to be only 35 C

i have two vantec 120mm stealth fans on the case, and a vantec aeroflow HSF (the TMD one)