New to P4 overclocking

[SonicIce]

Actually its my friends system. He has a 2.8GHz Prescott, Abit IC7-G, 2x512MB value RAM, and 6600 GT.

I don't know how differant it is from A64 overclocking. There are a few settings in his BIOS that I dont know what they do.

Here is his motherboard manual. The CPU settings start on page 42.
To set AGP/PCI ratio, do I set "AGP Ratio" to Fixed? What is "N/B Strap CPU As"? I figured out that 5:4 "DRAM Ratio" is DDR333. I guess these are the only settings that I need to modify.

What do we need to know to reach our goal of 3.4GHz? Is it easy to do on air cooling with these chips?

 

[Wentelteefje]

I found this over at Adrian's Rojak Pot...

The N/B Strap CPU As BIOS feature actually controls the setting of the external hardware reset strap assigned to the MCH (Memory Controller Hub) of the chipset. By setting it to PSB400, PSB533 or PSB800, you can trick the chipset into thinking that the 400MHz FSB or 533MHz FSB or the 800MHz FSB is being used.

When this BIOS feature is set to PSB800, you will be able to access the 800MHz CPU-to-DRAM ratios of 1:1, 3.2 and 5:4.

When this BIOS feature is set to PSB533, you will be able to access the 533MHz CPU-to-DRAM ratios of 1:1 and 4:5.

When this BIOS feature is set to PSB400, you will be able to access the 400MHz CPU-to-DRAM ratio of 3:4.

By default, this BIOS feature is set to By CPU, whereby the hardware strap will be set according to the actual FSB rating of the processor.

Generally, you do not need to manually adjust the hardware strap setting. But if you require access to the CPU-to-DRAM ratio that would normally not be available to you, then this BIOS feature would be very helpful indeed.

If you want to reach 3.4GHz, you'll have to reach a FSB of 243MHz... For this you'll indeed need the 5:4 divider, which will make your RAM run at 194MHz... If you mention there being a possibility to select this divider, it means that the mobo will have automatically selected the "PSB800" function for your CPU... So no need to touch that setting anymore...

"AGP Ratio" needs to be Fixed... However, if it is going to be easy/doable is another question... Prescotts do run very hot (hence "Preshots" ), so it might be that the overclock is limited because of the temps... How are his temps at stock?

You may need to buy a better HSF... If you do, get yourself a Zalman cooler or so... They'll keep that Prescott cool and quiet... BTW if you buy a better cooler, you may be able to rise to 3.5GHz, so your RAM will run at 200MHz again...

BTW, actually the 5:4 setting is more like a plain 160MHz, if you do the calculation...

 

[SonicIce]

Whoa, thanks dude! You answered all my questions thoroughly !

What is a safe maximum CPU tempurature? He said it gets to about 62C during gaming at 3.2GHz. His Northbridge fan drops to really low speed (600 RPM from normal 5000) once in a while so he may need to replace that also.

 

[Wentelteefje]

Yes! A

The maximum temperature of these CPU's (according to Intel) is 75°C... Your mate doesn't really have much headroom here, does he? Did he raise the voltage to get to 3.2GHz?

I'm afraid you'll have to buy yourself a better HSF if you want to push it further safely... While gaming is of course pretty intense, programs like Prime95 and OCCT (my favourite ) manage to stress your CPU even more... The (relatively unsafe) 70°C barrier could become reality with these torturers...

Buying a new HSF will cost a bit of money, especially if you want something that'll be notably better... There isn't that much offer for S478 anymore, but you could take a rather cheap Zalman, or go with one of its higher-end siblings... Nonetheless, this one will do a lot better than the stock HSF...

About, the NB fan... If that one drops to the 600 RPM while the system idles, there's no problem of course... If you're not sure about it, you could try to find the same on the FS/FT Forums... A very good one is pretty expensive for what you'll be getting, but this cheap CoolerMaster should do the job... However, the adhesive tape is pretty worthless, so you'll have to mod a bit...

BTW How's the ventilation of his case? If it's insufficient, a new cooler won't help much...

 

[Shimmishim]

Originally posted by: Wentelteefje
I found this over at Adrian's Rojak Pot...

The N/B Strap CPU As BIOS feature actually controls the setting of the external hardware reset strap assigned to the MCH (Memory Controller Hub) of the chipset. By setting it to PSB400, PSB533 or PSB800, you can trick the chipset into thinking that the 400MHz FSB or 533MHz FSB or the 800MHz FSB is being used.

When this BIOS feature is set to PSB800, you will be able to access the 800MHz CPU-to-DRAM ratios of 1:1, 3.2 and 5:4.

When this BIOS feature is set to PSB533, you will be able to access the 533MHz CPU-to-DRAM ratios of 1:1 and 4:5.

When this BIOS feature is set to PSB400, you will be able to access the 400MHz CPU-to-DRAM ratio of 3:4.

By default, this BIOS feature is set to By CPU, whereby the hardware strap will be set according to the actual FSB rating of the processor.

Generally, you do not need to manually adjust the hardware strap setting. But if you require access to the CPU-to-DRAM ratio that would normally not be available to you, then this BIOS feature would be very helpful indeed.

If you want to reach 3.4GHz, you'll have to reach a FSB of 243MHz... For this you'll indeed need the 5:4 divider, which will make your RAM run at 194MHz... If you mention there being a possibility to select this divider, it means that the mobo will have automatically selected the "PSB800" function for your CPU... So no need to touch that setting anymore...

"AGP Ratio" needs to be Fixed... However, if it is going to be easy/doable is another question... Prescotts do run very hot (hence "Preshots" ), so it might be that the overclock is limited because of the temps... How are his temps at stock?

You may need to buy a better HSF... If you do, get yourself a Zalman cooler or so... They'll keep that Prescott cool and quiet... BTW if you buy a better cooler, you may be able to rise to 3.5GHz, so your RAM will run at 200MHz again...

BTW, actually the 5:4 setting is more like a plain 160MHz, if you do the calculation...

5:4 at 243 is 194.4 or 194.

since it's 243*4/5 = 194.

 

[stevty2889]

Originally posted by: SonicIce
Whoa, thanks dude! You answered all my questions thoroughly !

What is a safe maximum CPU tempurature? He said it gets to about 62C during gaming at 3.2GHz. His Northbridge fan drops to really low speed (600 RPM from normal 5000) once in a while so he may need to replace that also.

At stock speeds/voltages throttling kicks in around 72c. If you increase the clock speed, and especialy the voltage, the throttling kicks in sooner. Be sure to run throttlewatch after overclocking to verify it's not throttling. Keep the temps under 69c, and you probably won't throttle unless you gave the vcore a big increase.

 

[SonicIce]

He didn't need to raise the voltage to get to 3.2. He said he is getting a 120mm zalman soon so he'll try to push it further when it comes. I'll tell him to run the stress tests.

 

[stevty2889]

Originally posted by: SonicIce
He didn't need to raise the voltage to get to 3.2. He said he is getting a 120mm zalman soon so he'll try to push it further when it comes. I'll tell him to run the stress tests.

BTW, I was running a 2.8 Prescott at 3.5ghz, 1.35v, and it didn't throttle, so his chip likely has some more potential.