# PSU for older Athlon XP-based PC



## JZ79 (Oct 7, 2008)

Can anyone help me please?

I recently upgraded my aging system with a new Radeon 3650 AGP card, together with a new PSU - Corsair 450 VX (ATX 2.2 standard).
*****************
My system specs:
MB: nforce 2-based MSI K7N2 Delta ILSR
CPU: (Socket A) AMD Athlon XP 2500+(Barton)
RAM: 2 x 512MB DDR400
GPU: Sapphire Radeon HD 3650 512MB DDR2 AGP
HDD: 160GB 7200 rpm
PSU: Corsair VX450 W (+3,3V 20A, +5V 20A, +12V 33A. Max output on +3.3 & 5V = 130W) http://www.corsair.com/products/vx.aspx

My problem is that I am experiencing hangs and crashes in gaming, display goes into "Power Saving Mode".

I suspect it might be a power supply related issue. I've been trying to find out if the Athlon XP 2500+ is powered from the +5V or +12V rail (on some forums people say that unlike contemporary CPUs, the older Athlon XP CPUs are indeed powered from the +5V rail and not 12V rail) but haven't come across any official / reliable info so far.
Although my new PSU is 450W, it only provides max of 130W on the +3.3 and +5V rails - and I'm not sure if that is enough. I am no longer sure I picked the appropriate PSU for my system.
Shall I rather go for a PSU of the older 2.0 standard - with more powerful +3.3V and +5V rails? Also, I'm not sure if my components - even the new Radeon card utilize the +12V rail at all (besides the usual stuff i.e. HDD, fans), is this video card perhaps powered from the +5V rail as well?

I have also tried to use my original PSU, it’s a no-name 300W ATX 2.0 standard PSU with 20A on +3.3V, 30A on +5V, and 12A on +12V rail. The combined MAX wattage of +3,3V and +5V is said to be 180W but it’s very likely to be much less since it’s a no-name and it’s 5 years old now. In any case – the system behavior is the same even with this original PSU.

Any clues, recommendations would be greatly appreciated!

Thanks All!
Rgds,
JZ


----------



## speedster123 (Oct 18, 2006)

*Re: PSU for older Athlon XP-based system*

one of my rigs has a barton 2500, video ti4200, low end.
i replaced the supply with an antec 550 trio.
:tongue:


----------



## Tumbleweed36 (May 14, 2005)

*Re: PSU for older Athlon XP-based system*

Look at your bios when you first start up and check the voltages and temperatures and report them back here. 

I doubt if you will find a better 450 watt power supply than you have for raw power. I am not saying that 450 is enough, but if this power supply is O.K. (like not faulty), it is an excellent 450 watt supply.

Just for testing purposes, do you have another video card that you could slip in there to test with and hopefully a less power hungry card (although that card you have is not considered a power hungry card)?


----------



## Stu_computer (Jul 7, 2005)

*Re: PSU for older Athlon XP-based system*

The Athalon series dates back to 1999. Athalons have used two different mountings, the first was Slot A, next came the Socket A (462). All Athalon models require an external cpu voltage of 3.3 volts supplied from a voltage regulator (VR), it's the source voltage to the VR that often causes confusion.

The old processors (pentium II, III, Slot A era) typically sourced from the 5Volt rail.

The Athlon Socket A(462) is sourced from the 12Volt rail. (re: AMD Builder's Guide)

Core Voltages for:
Athlon Slot A is 1.6 ~ 1.8V
Athlon Socket A(462) is 1.6 ~ 1.8V
Athlon XP Socket A(462) is 1.75V
note: check cpu internal revision and clock speed for correct core voltage settings.

Your Athlon XP draws about 8Amps from the 12V rail.


----------



## ebackhus (Apr 21, 2005)

*Re: PSU for older Athlon XP-based system*

My girlfriend's PC with an Athlon XP 3200+ is using a 650w PSU and runs great.

+5v - 32a
+12v - 38a
+3.3v - 24a


----------



## Pauldo (Jun 22, 2008)

You are using an ATI graphics card on an nForce motherboard. The two don't mix very well, hardly at all with integrated graphics.

What graphics card were you using before this upgrade? Was it the onboard graphics?

Pauldo


----------



## Doby (Jan 17, 2006)

The 2500 barton is powerd by the 12v rail that why you need to plug in the 4 pin aux 
12v.

You do have that pluged in correct?

You should be fine with the corsair 450W with that setup, I would start looking elsewere such as drivers or ram issues.

First post your temps and voltages, the bartons need to be kept below 60C.

Your running ddr 400, and the fsb on the 2500 is 333, sometimes, not always, the bartons need to run in sync with the ram clock and the cpu clock for max stability so try underclocking the ram to 166mhz in bios


----------



## JZ79 (Oct 7, 2008)

Thanks you All for your thoughts so far, here is my feedback:

In BIOS my temperature and voltages read as following:

CPU: 42 C

Vcore: 1.61V
+3.3V: from 3.21 to 3.24
+5V: 4.94V
+12V: from 11.97 to 12.03V
-12V: -11.78 to -11.86V
-5V: 0V
5VSB(V): 4.89V

Before my Radeon 3650 upgrade I was also running a Radeon card, a low-end 9200 and had no stability issues at all. I still have the card so I'm going to swap them and will let u know the result.

Also, I have the ATX12V power connector (4 pin AUX) plugged in of course.

Re drivers, I'm running the latest Catalyst v8.9 HOTFIX for AGP.


----------

