Is a 300W ps necessary to overclock?

[hardmankam]

Hi all,

My week41 duron700 can only o/c to about 888 (8*111), I cannot overclock it higher than 900MHz. But i think at 8*111, it beats 9*100 since the bus speed is so high. The only thing I can think of it not going over 900MHz is my power supply. It is only a 250W unit. Would a 300W power supply put me over 900Mhz?

By the way, I have a FOP32 h/s and have tried 1.850V already, still, it would give me a black screen if I set anything higher than 900MHz at POST.

Thanks,

HK

 

[jinsonxu]

It is not true that the more watts the power supply unit, the better.
Many people are getting bigger and bigger power supply unit. The vendors also push the higher watt power supply unit because there is more profit.

In all electronics or engineering, there is a factor known as the bell curve. For current technology and size of power supply, the peak is 235 watt.

There are a few important factors to look for in a power supply unit.

For newer chipset which draws a lot of current during standby, the 5v+ standby has become important. Choose one that is about 1 amp or more. Wake-on LAN and Wake-on modem add to this demand as they draw from this 5v+ standby, so if you don't need it, don't connect these features.

Quality of power supply is important. Choose those with CE approval. Check inside to see if the input has an input filter system. This is kind of difficut if you are not electronic trained. Watch out for units that can be remarked with a higher rating. If there are several rating, look inside them to compare. Higher rating power supply unit have bigger heatsink.

Another factor to look out for in getting power supply is the fan. You can see the rating of the fan.

The larger rating power supply unit have larger and more components. This restrict air flow to cool the internal heatsink. Law of reliability states that the more you have, the larger the probability of failure.

For your information, a 235 watt power supply is enough for dual PII-450, 3 HDD, CD ROM, TNT, LAN and SB128 and 4 fans. To be precise, the consumption is 145 watt.
A similar configuration with an Athlon 800MHz would not need any more than the above.
A T-1000 MHz with HSF, video card and mobo uses only 45 watt. When fully running, its requirements goes up by another 25 watt.
From these, a inactive window display of most CPU would be around 120 watt climbing to 180 watt on full activity. You get a 300 watt unit if you have a lot of peripherals like disk, CDRW, DVD, 10,000 rpm hdd, etc.

There is an instrument to measure the exact current and power of the computer. It is a DC-hall-effect clamp ampmeter. About $200. USD

 

[jinsonxu]

You'll want a PSU that can provide at least 150Watts on the 3.3V and +5V rails. Also, make sure that the 5V standby current is at least 1 amp or more.

Although the +3.3V rail can sustain 14A while the +5V can sustain 25A, this rating is taken provided that only one of them is used, ie no load on all other voltage rails. If you use them together (just like in any PC setup), then the maximum current these rails can actually supply is lower than what they've stated here because some power will be drawn to the other rails as well (they're all interconnected).

So when you connect your PSU up to a PC, the maximum currents that your PSU can supply are not 14A and 25A anymore. So a much more accurate way of judging the load rating of the PSU on these two rails (and any others as well, but these two are most important because they power the CPU and motherboard) is to use the combined rating. What the combined rating means is that if both the +3.3V and +5V rails are being used, and as long as the current on any one of the rails does not exceed the stated current limit for that rail, then the total power (3.3*I1 + 5*I2) cannot exceed that combined rating regardless of current. The 5v or the 3.3 v are normally supplied to the CPU.

On the mobo is a voltage regulator which supply the one point what-ever volt to the CPU. These regulator can take the 5v or the 3.3 v to switch it to the required voltage.

The other reason that the 5v and 3.3v are interelated, the switching transformer have a secondary at 5v with a tap on the same winding for 3.3v . If you are familiar with transformer, you will understand this simple concept of the 5v seconday with a 3.3v tap.

Some good PSUs to get are Enermax 350W, Xenac 370W, Enlight HPS-300-101 300W.

 

[jinsonxu]

What are your CPU temperatures? Have you tried 9X multiplier? If teh multiplier failed, did you repencil your chip? Turn down the FSB to 100 and try to first get an idea of how much your chip can reach.

 

[hardmankam]

jinsonxu: Thanks for the detailed explaination on the PS issue.

my full load temp is about 45C or 113F.

I know my memory can take me to about 110mhz+PCI since that is what i am running right now (8*110=880). I am having trouble running even 8.5*105=893 or 9*100=900. It can POST but will not load windows even at 1.85V. At 9.5*100=950, I would only get a black screen, no even POST. Just a reminder that this is a Week41 Duron700 and I thought a late week like week41 can hit 950 easily... i guess not.

As for my 250W PS, it is not a name brand or anything, just a generic one. I am running 2HD, 1cd-rom and 4or5 fans in my case (maybe i am running too many fans, but i think fans draw very little power). Anyway, at 880MHZ it is running pretty fast because of the high bus speed.

HK

 

[toph99]

you might want to check for anything else which is running warm, such as the north bridge(unless you have an Abit KT7 because they have the fan on there already) if you have a frien who has a high quality power supply(like an Antec one or anything on AMD's Approved list) you might want to borrow it to see if it makes a difference